Model-based interpretation of solute exports and carbon partitioning during shale weathering in a mountainous hillslope - Lucien Stolze; Dipankar Dwivedi; Carl I. Steefel; Sergi Molins; Wenming Dong; Curtis A. Beutler; Alexander W. Newman; K. H. Williams (Water Resources Research, 2026)

Snow microphysical processes in orographic turbulence revealed by cloud radar and in situ snowfall camera observations - A. Kotsche; Maximilian Maahn; V. Ettrichrätz; Heike Kalesse-Los (Atmospheric Chemistry and Physics, 2026)

Depth of nutrient uptake by deep-rooted plants is regulated by water availability - Langlang Li; J. N. Christensen; Markus Bill; Wenming Dong; Yuxin Wu; Curtis A. Beutler; Matthias Sprenger; Brian Gulick; Sharon Bone; Boris Faybishenko; John Sanders; Chunwei Chou; et al. (PNAS, 2026)

Warming winters are disrupting the hidden world of fungi – the result can shift mountain grasslands to scrub - Stephanie N. Kivlin; Aimee T Classen; L.A. Souza (The Conversation, 2026)

An actinopterygian-dominated fish fauna from the Upper Cretaceous Williams Fork Formation, northwestern Colorado, and evidence for provinciality across Laramidia at the Campanian/Maastrichtian boundary - Joel Crothers; Jaelyn Eberle; Donald B. Brinkman; Alyssa Wurtz; Andrew Heckert; ReBecca K. Hunt-Foster; John R. Foster; Ida C. Dirkes; R. R. Dunn (Cretaceous Research, 2026)
The Williams Fork Formation (WFF) of northwestern Colorado preserves an understudied freshwater biota from the Campanian/Maastrichtian boundary. Here we describe a diverse actinopterygian-dominated fish assemblage from the ReBecca’s Hollow locality of Rio Blanco County. Chondrichthyans are rare from this site, but include a hybodontid, Lonchidion , and the hemiscyllid Chiloscyllium . A fragmentary element may represent a pycnodontiform. Chondrosteans are represented by a tentative acipenserid. Holosteans include the lepisosteids Atractosteus and an unnamed taxon, and the amiids Melvius , Cyclurus and Palaeolabrus . Teleosteomorphs at this site include Belonostomus , Paralbula casei , Coriops , Estesesox foxi , Acronichthys , hiodontids, and acanthomorphs. This locality yields at least 17 fish taxa, most of which have not been described previously from the WFF. Although the WFF is temporally correlative with the St. Mary River and Horseshoe Canyon Formations in Alberta and the Prince Cr

Wind-driven seed dispersal differentially promotes seed trapping and retention across alpine plants - C. A. Ray; Savannah Troy; E. V. Xie; T. M. Jenkins; G. Belfry; A. Wells; P. de Valpine; B. Blonder (American Journal of Botany, 2026)

The Colorado River: Chasing Water - David J. Robertson (Natural Areas Journal, 2026)

Experimental warming decouples plant-fungal symbiont interactions and leads to a more conservative ecosystem - L.A. Souza; Aimee T Classen; Jennifer A. Rudgers; Charles Miller; J. A. M. Pyle; R. Simberloff; J. Fordyce; J. Harte; Stephanie N. Kivlin (PNAS, 2026)

Increasing aridity may threaten the maintenance of a plant defence polymorphism - L. Carley; T. Mitchell-Olds; William Morris (Ecology Letters, 2025)
It is unclear how environmental change influences standing genetic variation in wild populations. Here, we characterised envi- ronmental conditions that protect versus erode polymorphic chemical defences in Boechera stricta (Brassicaceae), a short-lived perennial wildflower. By manipulating drought and herbivory in a 4-year field experiment, we measured the effects of driver variation on vital rates of genotypes varying in defence chemistry and then assessed interacting driver effects on total fitness (estimated as each genotype's lineage growth rate, λ) using demographic models. Drought and herbivory interacted to shape vital rates, but contrasting defence genotypes had equivalent total fitness in many environments. Defence polymorphism thus may persist under a range of conditions; however, ambient field conditions fall close to the boundary of putatively polymorphic environment space, and increasing aridity may drive populations to monomorphism. Consequently, elevated intensity and

Is social plasticity good? Does lifetime social variation enhance LRS and longevity in yellow-bellied marmots? - T. Blakely (2025)
Social relationships have important fitness consequences in many taxa. Much of the prior literature on the adaptive value of social relationships has looked for associations between social network position, or social structure, and fitness correlates during a single period of time–often a year. However, individuals often vary in the strength and number of their relationships across their lifetimes. Thus, we asked whether deviations from an individual’s lifetime average social patterns, as measured using a set of social network statistics, were associated with lifetime reproductive success (LRS) and longevity in yellow-bellied marmots (Marmota flaviventer). We expected that increased social plasticity would be positively associated with both LRS and longevity, as deviations from lifetime average social network traits are associated with increased fitness at the annual scale. We used 20 years of data on social connectedness to fit a double hierarchical generalised linear model, which est

Effects of elevation on salamander life strategies - T. Bulot (2025)
The Arizona Tiger Salamander (Ambystoma mavortium nebulosa) is a keystone species in the Rocky Mountains. Depending on how well they grow as larvae, these salamanders can either metamorphose to have terrestrial traits at maturity or retain their juvenile aquatic traits as adults. We expect that ponds at lower elevations, which are warmer and have longer growing seasons, will support faster growth, resulting in larger paedomorphs. To test this, salamanders will be surveyed at sites ranging from about 8,000 to over 11,000 feet in areas surrounding the RMBL townsite. Using dip nets, seine nets, and fyke nets, individuals were caught, recorded whether they were metamorphic or paedomorphic, measured for snout-vent-length (mm), weight (g), and noted their sex. Findings will be compared with climate data at each site and added to the ongoing 2020-2024 dataset.

Wild marmots’ social networks reveal controversial evolutionary theory in action - Conner S. Philson; Daniel T. Blumstein (The Conversation, 2025)

Rare species do not disproportionately contribute to phylogenetic diversity in a subalpine plant community - Leah N. Veldhuisen; Verónica Zepeda; Brian J. Enquist; Katrina M Dlugosch (American Journal of Botany, 2025)
We found that rare species, whether at low abundance or with a small range, do not disproportionately contribute to phylogenetic diversity in our subalpine plant community. These results were consistent across elevations. Instead, rare species might provide phylogenetic redundancy with common species. Deeper understanding of functional differentiation is needed to understand contributions of rare species to this system.

Harmonized aerosol size distribution, cloud condensation nuclei, chemistry and optical properties at 10 sites - E. D. Andrews; I. Zabala; G. Carrillo-Cardenas; G. Titos; J. A. Casquero-Vera; A. Gannet Hallar (Scientific Data, 2025)

Testing the marginal value theorem on Bombus appositus and Bombus nevadensis - Kevin Ryan (2025)
Previous studies on bumblebee foraging behavior found that bumblebees often exhibit optimal foraging behavior when collecting nectar and pollen. A popular theory is that bumblebee foraging can be represented by the marginal value theorem (MVT). This summer, I observed the foraging behavior of Bombus appositus and Bombus nevadensis workers in Gothic, Colorado, to analyze whether bumblebee foraging decisions on naturally occurring Delphinium barbeyi patches are consistent with the MVT. Specifically, I investigated 1) Do B. appositus and B. nevadensis workers spend more time foraging in denser patches of D. barbeyi, 2) do B. appositus and B. nevadensis workers visit proportionally fewer flowers in denser patches of D. barbeyi, and 3) are these trends less apparent at the end of the summer when all patches are D. barbeyi are more sparse. After following bumblebees throughout their foraging bouts and tracking their foraging decisions with a voice recorder, I found that patch flower density

Females know best: dispersal polymorphism maintained by sex-specific foraging - E. M. Johnston; H. H. Whiteman; H. S. Greig; B. J. Olsen; A. J. Klemmer (Behavioral Ecology and Sociobiology, 2025)

Biotic and abiotic drivers of pathogen prevalence in a rust fungus with multiple plant hosts - I. Ferrer (2025)
Pathogens can have strong negative effects on individual fitness that scale up to influence population dynamics. Because of this, understanding the ecological contexts that shape pathogen transmission and prevalence is critical for understanding community dynamics and ecosystem function. Puccinia monoica is a fungal pathogen with a complex life cycle that alternates between infecting grasses and forbs in the Brassicaceae. This study investigates how B. stricta and grass host densities, as well as abiotic factors such as drought, influence transmission of P. monoica. I conducted field surveys near Gothic, Colorado, to quantify environmental conditions across multiple sites with variation in host and pathogen abundance. Furthermore, to experimentally test the potential role of drought in facilitating pathogen spread, I performed controlled inoculations of grass hosts under drought and control conditions in a greenhouse. These integrated field and experimental approaches helped reveal how

Evaluating differences in water temperature and macroinvertebrate communities in BDA ponds, stream pools, and beaver dam ponds - R. Hinke (2025)
Beaver Dam Analogues (BDAs) are human-made structures mimicking beaver dams and are implemented in restoration projects to slow flow, aggrade sediment, and reconnect streams to floodplains or create wetland conditions. Despite the recent popularity of this technique, very little monitoring occurs at BDA sites. This study involved surveying and measuring beaver augmented BDA ponds, BDA ponds, and stream pools to assess differences in temperature and macroinvertebrate communities as an evaluation of how successful BDA installation has been. For each type of lentic habitat, we measured six different sites to get an accurate composition of the ecosystem for our data. Using temperature loggers and d-nets, we measured each restoration site over a period of 10 days. We found that the BDA ponds were comparable to beaver augmented BDA ponds in temperature, though the beaver-augmented ponds had a slightly lower mean daily maximum. In contrast, stream pools had a wide range of temperature fluctua

Up high, hot and dry: Individual reproductive output in subalpine bees declines with increasing drought severity - Lydia H. Wong; B. D. Inouye; J. R. K. Forrest (Global Change Biology, 2025)
Wild bees play indispensable ecological roles in many ecosystems, yet declines in many species have been documented in recent years. These declines have been linked to numerous anthropogenic pressures, including climate change, which can influence bee populations directly (i.e., via physiological mechanisms) and indirectly (e.g., through changes to floral resource quantity and quality). Widespread changes in the distributions and abundances of many bee species have been linked to climate change at large spatial scales; yet, the local-scale processes that generate these broad-scale patterns are little known. Specifically, it is unclear how climate change influences the fitness of individual bees, despite the fact that broad-scale patterns of decline must be driven by individual-level processes. Our study examines the individual fitness responses (i.e., reproductive output) of five solitary bee species in the genus Osmia to variations in local climate variables in subalpine habitats. Ove

Temperature influences pollinators' choice of floral partners independently of community composition - Kaysee Arrowsmith; M. D. Strait; M. Chandar; A. Schiffer; B. J. Brosi (Journal of Animal Ecology, 2025)

Remote sensing strategies for surface mineral and contaminant detection - Kathleen Grant (2025)

Biofluorescence in Arizona Tiger Salamanders (Ambystoma mavortium nebulsoum) as an indicator of sexual readiness - K. Killian (2025)
Biofluorescence, the emission of visible light by organisms following the absorption of shorter wavelengths of light, has been identified recently in various amphibians but remains poorly understood in salamanders. This study investigates the potential relationship between biofluorescence and sexual readiness in Ambystoma mavortium nebulsoum, the Arizona tiger salamander. Specifically, we analyzed maximum gray values of the tail, cloaca, and full body through creating regions of interest from fluorescence images of the underbelly of animals in relation to morph (paedomorph and metamorph), sex, and degree of cloacal swelling, which serves as an external indicator of sexual readiness. Fluorescence was quanitified using ImageJ from standardized photographs of 146 individuals. ANOVA tests revealed significant differences in tail brightness between morphs (p > 0.05), confirmed by Tukey’s HSD post hoc tests (adjusted p < 0.05). Although sex differences in tail brightness were initially detec

Does sodium in floral nectar enhance pollination & plant reproduction? - M. Hunt (2025)

Herbivory and water availability interact to shape the adaptive landscape in the perennial forb, Boechera stricta - M. I. Jameel; L. Duncan; K. A. Mooney; J. T. Anderson (Evolution, 2025)
Corydalis caseana ssp. brandegei (Fumariaceae) is a perennial plant that grows in moist, subalpine regions of south central Colorado, USA. Prior to this study, nothing was known of its reproductive biology. The most numerous visitors (59%), and the only known pollinators, were long-tongued bumblebees (Bombus appositus). Twenty-nine percent of visits were from short-tongued nectar-robbing bumblebees (Bombus occidentalis). Hum- mingbirds also visited the flowers but they did not pollinate them. Corydalis caseana flowers remained open and in good condition for approximately 4 days. During that time, in the absence of visitors, nectar containing 35% sugar accumulated at a rate of approxi- mately 1 mL per day. Corydalis caseana has a mixed-mating system. It is self-fertile, but the self-fertilized flowers produce fewer seeds per fruit than the outcrossed flowers (a mean of 2.9 compared with a mean of 4.7). Results suggest a possibility of inbreeding depression.

The effect of human pressure on the flight initiation of montane breeding birds throughout the summer breeding season - L. Higgins (2025)
The summer is a peak tourism season in the Colorado Rocky Mountains, but is also the breeding season for many montane bird species, resulting in an increase in bird-human interactions and coexistence. I measured the effect that human activity has on the flight initiation behavior of two montane bird species: the American Robin and the Mountain White-crowned Sparrow. I also looked at how these effects change over the course of the breeding season. I measured the flight initiation distance of individuals in high, moderate, and low human activity areas over the course of the breeding season to observe this. This research is important because human activity in wild spaces is increasing and understanding how birds respond and adapt to human activity is essential for their conservation. ​

The impact of soil moisture, nectar production, and spectral reflectance on hummingbird visitation patterns to the Scarlet Gilia (Ipomopsis aggregata) - A. M. Pantoja Alfaro (2025)
Climate change has brought intense disruptions to the natural patterns of growth and reproduction in sub-alpine ecosystems, generating changes to the food sources that Broad-tailed hummingbirds (Selasphorus platycerus), which breed in the Rocky Mountains, depend on. A hotter, dryer climate results in changing levels of soil moisture, which may impact floral traits such as color and sugar concentration in nectar. In order to find out how variations in these traits impact hummingbird visitation rates to certain flowers, we used data from HummerFlowerWatch, a long-term study gathering camera trap data (documenting every time a hummingbird visits a chosen flower) and transect data (measuring flower abundance), we collected specimens of the native Ipomopsis aggregata flower in Gothic, CO, and we noted the trail and measured soil moisture, glucose concentration in nectar, and spectral reflectance to determine correlations between these variables. We predicted higher soil moisture in Stupid F

Understanding aquatic insect oviposition to increase aquatic insect recruitment rates - C. S. Baker (2025)
Aquatic insects play many critical ecological roles in their environments. Anthropogenic changes in these environments, particularly those already under stress, leave the insect community more prone to stochastic disturbances. Despite widespread efforts by conservationists, many projects fail to increase insect recruitment to pre-disturbance levels as much of the focus is centered on the larval stage. It is currently unknown how aquatic insects select sites for laying egg masses, a process known as selective oviposition. We aimed to understand the characteristics of emergent rocks favorable for insect-selective oviposition. We hypothesized that rock size would have the most significant impact on favorability and insect success rates. Data was collected in the East River in the Colorado Rockies, on the RMBL campus. These pairs of emergent rocks exhibit various qualities, including rock embedment, water flow rate, and rock size. We observe insect behavior using a time-lapse camera. Egg m

Spatial and Temporal Variation in Phylogenetic Diversity in Rocky Mountain Plant Communities - Leah N. Veldhuisen (UA Campus Repository (The University of Arizona), 2025)
Phylogenetic diversity is an axis of biodiversity that captures the variation in evolutionary relationships present in a community, and is associated with important ecosystem functions. Interestingly, recent work has shown that phylogenetic diversity is often decoupled from other biodiversity metrics, such as richness and functional diversity. Phylogenetic diversity correlates more positively with biomass than does species richness or functional diversity, and promotes ecosystem stability, productivity and resistance to invasion. However, phylogenetic diversity is threatened by species loss and phylogenetically clustered extinction. Given the ecosystem benefits of phylogenetic diversity and its independence of other diversity metrics, it is critical to better understand its distribution and how it may respond to climate change. In this thesis, I investigate spatial and temporal variation in phylogenetic diversity in Rocky Mountain plant communities at the Rocky Mountain Biological Labo

The role of snowmelt and subsurface heterogeneity in headwater hydrology of a mountainous catchment in Colorado: A model-data integration approach - L. Wang; Zexuan Xu; L. Wang; R. Thibaut; Craig Ulrich; Matthias Sprenger; Sebastian Uhlemann; Yuxin Wu; E. L. King; Haruko M. Wainwright; R. W. H. Carroll; Curtis A. Beutler; et al. (Water Resources Research, 2025)
Abstract Mountainous headwater streams are sustained by both snowmelt‐driven streamflow and groundwater discharge in the Upper Colorado River Basin. However, predicting headwater stream discharge magnitude and peak flow timing is challenging in mountainous terrains, where snowmelt rates vary with vegetation type and elevation, and heterogeneous subsurface physical properties influence groundwater storage and its release. We used a model‐data integration approach to investigate the roles of snowmelt and subsurface structure in stream discharge and groundwater level. We ran an ensemble of 100 integrated surface‐subsurface hydrologic models for a mountainous headwater catchment near Crested Butte, Colorado, USA. We also evaluated and calibrated these models against observed data sets, including snow depth measurements using distributed temperature probes, stream discharge, and groundwater levels. Calibration with multiple data sources using neural density estimators has further constraine

Host species and geographic location shape microbial diversity and functional potential in the conifer needle microbiome - R. M. Bowers; S. Bennett; R. Riley; J. C. Villada; I. R. Da Silva; T. Woyke; A. C. Frank (Microbiome, 2025)

Vegetation structure effect on bird foraging behavior across the summer season in montane wet-meadows - T. Blakelock (2025)
Mountain White-crowned Sparrows and Wilson’s Warblers rely on foraging microhabitats in montane wet meadows during the breeding season to find food for themselves and their offspring. The microhabitats are comprised of vegetation, which can be food itself, but it can also be a substrate for invertebrates that birds can consume. I investigated the differences in foraging microhabitat vegetation structure between these two species by conducting foraging observations accompanied by vegetative surveys. Observations took place in two survey periods to account for food availability and breeding season interferences: late June to early July and mid-July to late July. I found that vegetative structure had no significant effect on foraging efficiency. Additionally, neither bird was found to be significantly more efficient at foraging. I found that the two target birds forage significantly more efficiently later in the season.

Quantifying groundwater response and uncertainty in beaver-influenced mountainous floodplains using machine learning-based model calibration - L. Wang; T. Babey; Zach Perzan; Samuel Pierce; Martin Briggs; Kristin Boye; Katharine Maher (Water Resources Research, 2025)
AbstractBeavers (Castor canadensis) alter river corridor hydrology by creating ponds and inundating floodplains, and thereby improving surface water storage. However, the impact of inundation on groundwater, particularly in mountainous alluvial floodplains with permeable gravel/cobble layers overlain by a soil layer, remains uncertain. Numerical modeling across various floodplain structures considers topographic and sediment complexity and multidirectional flow, linking inundation to groundwater response. This study develops a model‐data integration workflow to address uncertainty in groundwater response to beaver‐induced inundations in a mountainous alluvial floodplain in the Upper Colorado River Basin. Uncertain factors include seasonal hydrologic dynamics, hydraulic conductivities, floodplain structures, and meteorological forcings. We employed an ensemble of groundwater models, based on geophysical and hydrologic data, with machine learning‐based calibration using a neural density

Differences in gene expression and genetic variation underlying preference-performance mismatches: insights from a specialized native herbivore on an invasive toxic plant - Nitin Ravikanthachari; C. L. Boggs (Heredity, 2025)
The causes for preference-performance mismatches in a specialist native herbivore laying eggs on an invasive toxic plant are investigated, and genes related to successful detoxification and adaptive feeding were enriched in larvae feeding on native plants and toxic plants.

Courtship display behavior influences tail myology in Centrocercus minimus (Gunnison sage‐grouse) - Samantha J. Clark; Jessie Atterholt; Samantha J. Clark; Nathan Seward (Journal of Anatomy, 2025)
Abstract A variety of bird species engage in complicated, elaborate courtship displays to impress potential mates. Such displays include wing flaring, aerial acrobatics, choreographed dances, and tail fanning. Though these behaviors are often well studied, the underlying musculature facilitating them is poorly understood. Exemplars of unique avian courtship behaviors include species of the North American sage‐grouse ( Centrocercus ). Each spring, males gather in leks where they perform courtship displays which incorporate species‐specific sound production, nape feather movement, and importantly, the raising and spreading of their rectricial fan for prolonged periods of time. Here we describe the tail myology of the lekking sage‐grouse species Ce . minimus (Gunnison sage‐grouse). We compare the tail myology of this species to that

Reproductive ecology and pollination biology of Geum triflorum (prairie smoke) - K. Hughes (2025)
Understanding plant reproductive strategies is important for interpreting population dynamics and species resilience. We investigated the mating system, pollen limitation, and pollinator interactions of Geum triflorum (prairie smoke), a subalpine wildflower. Experiments took place at the Rokcky Mountain Biological Laboratory in Gothic, CO. Using a randomized block design, we applied five pollination treatments: hand outcross, open outcross, hand self, autogamy, and control. We measured seed set, floral traits, and pollinator identity and activity in 26 naturally occurring G. triflorum rosettes. However, due to severe drought stress, widespread herbivory, and issues with pollinator exclusion bags, only three flowers produced seeds across all treatments. This precluded statistical analysis of reproductive success. Despite these limitations, results suggest G. triflorum does not reproduce via autonomous self-pollination and may be capable of some amount of self-fertilization via geitonoga

Diurnal trends and meteorological factors influencing the variability of fluorescent bioaerosol in Mt. Crested Butte, Colorado during SAIL - A. Sayeed Md Shawon; Katherine Benedict; A. Gutierrez; Allison Aiken (Journal of Geophysical Research: Atmospheres, 2025)
Abstract Despite the crucial role of bioaerosol particles (BAP) in our climate system, local ecosystems, and human health, our grasp on their atmospheric interactions is hampered by a lack of high‐resolution and long‐term data, which is essential for understanding their abundance and variability in response to meteorological conditions. To discern these relationships in a high‐altitude mountainous terrain is even less well‐studied. Therefore, we deployed a Wideband Integrated Bioaerosol Sensor (WIBS‐Neo) for three months during the first biologically active season of the Surface Atmosphere Integrated Field Laboratory (SAIL) campaign in summer 2022 on Mt. Crested Butte in Colorado (elevation 3,140 m ASL). Here, we report real‐time fluorescent BAP (FBAP) data collected from 15 June to 13 September 2022, sampled from within the ARM Aerosol Observing System (AOS). To our knowledge, these are the first high altitude (>3,000 m ASL) continuous measurements of FBAP made in North America. Du

Range-wide study in a sexually polymorphic wild strawberry reveals climatic and soil associations of sex ratio, sexual dimorphism and sex chromosomes - N. Cullen; E. Richardson; T. Budinsky; R. Reeb; S. Mortimer; A. Liston; T. L. Ashman (Journal of Ecology, 2025)

Shorter seasonal snow cover poses a risk to solitary bee populations in a mountainous ecosystem - G. Quinlan; Melanie R Kazenel; M. Stemkovski; R. E. Irwin (Proceedings of the Royal Society B: Biological Sciences, 2025)

Comparing decomposition rates and detritivore preferences for caddisfly (Trichoptera) cases versus ambient detritus - E. Madden (2025)
Humans manage microbes in their built environments by lowering humidity, filtering outside air, and applying antimicrobials that together fosters the selective dominance of microorganisms that can tolerate these harsh conditions and selects for antimicrobial resistance. Other species, however, regulate decomposition of their built environments in warm, moist conditions with diverse microbial communities. For example, larval caddisflies that live in streams and ponds use their labial silk glands to weave detritus, pebbles, and other materials into portable cases. Premature decomposition of cases is detrimental to these invertebrates, as cases serve as protection for vulnerable larvae against predation, aid in respiratory efficiency, and ensure reproductive success of adults. Plant-based cases remain in wetland ponds in Colorado’s East River valley for up to nine months after caddisfly pupation and case abandonment, while the same detritus not associated with cases is absent from the pon

Linking surface processes, solute generation, and CO2 budgets across lithological and land cover gradients in Rocky Mountain watersheds - J. R. Slosson; I. J. Larsen; M. J. Winnick; J. M. Marmolejo-Cossio; K. H. Williams (Water Resources Research, 2025)
Abstract Chemical weathering in mountain critical zones controls river chemistry and regulates long‐term climate. Mountain landscapes contain diverse landforms created by geomorphic processes, including landslides, glacial moraines, and rock glaciers. These landforms generate unique flowpaths and water‐rock interactions that modify water chemistry as precipitation is transformed to streamflow. Variations in lithology and vegetation also strongly control water chemistry. Prior work has shown that landslides generate increased dissolved solute concentrations in rapidly uplifting mountains. However, there is still uncertainty regarding the magnitude which different geomorphic processes and land cover variations influence solute chemistry across tectonic and climatic regimes. We measured ion concentrations in surface water from areas that drain a variety of landforms and across land cover gradients in the East River watershed, a tributary of the Colorado River. Our results show that landsl

Assessing anthropogenic effects on golden-mantled ground squirrel and least chipmunk flight initiation distances - S. Mikaru (2025)
Species who commonly occupy territories within human settlements are exposed to frequent human disturbance, which has been linked to significant shifts in wildlife behavior in past studies. As urbanization and rural development continue to increase, we can anticipate cohabitation between humans and wildlife to also increase, creating a growing need to understand the effects of repeated human disturbance on wildlife behavior across a variety of taxa. Flight initiation distance (FID) is a common metric used to quantify antipredator behavior and boldness in wildlife populations and is used to assess perceived risk of a pursuer from the perspective of a fleerer. We conducted FID trials on golden-mantled ground squirrels (Callospermophilus lateralis; GMGS) and least chipmunks (Tamias minimus; CPMK) across 11 sites of varying levels of human disturbance to determine the effect of human disturbance on FIDs through a generalized linear mixed effects model. We found a statistically significant

The effects of snowmelt date, soil moisture, and precipitation on nectar and floral morphology of Ipomopsis - F. Morrison (2025)
Climate change is putting montane plant species at risk that rely on historical patterns of precipitation and snowmelt timing. Floral traits, such as nectar production and morphology can be impacted by water availability. Hybridization of plants has the potential to provide adaptation to climate change through an increase in genetic variation. This study looked at nectar production and concentration, corolla length, stamen length, and style length in response to snowmelt date, summer precipitation, and soil moisture content. The focus populations included Ipomopsis aggregata and hybrids of Ipomopsis aggregata and Ipomopsis tenuituba. I expected that nectar production, corolla length, stamen length, and style length would decrease as water availability in the soil decreased, while nectar concentration would increase. I also predicted that floral traits would respond less to water availability in hybrids than I. aggregata due to their more efficient water usage and occupation of drier, r

Different aspects of dominance are not equivalent when testing for trade-offs in ant communities - A. S. Nelson; K. A. Mooney (Ecology and Evolution, 2025)

Using time-lapse imagery to determine snow heterogeneity - G. Elovitz (2025)

Alpine plant spatial clumping modifies leaf surface temperature - E. Ramsey (2025)
Alpine plant communities are particularly susceptible to the impacts of climate change, which makes predicting how these communities will respond important for their conservation. This can be better predicted by understanding how the communities assemble, which is highly influenced by species interactions like facilitation. In alpine environments, clustered plants may experience facilitative interactions that can improve vital rates like survival and fecundity. Alpine facilitation is known to occur via increased soil moisture and buffered air temperatures, but this is likely not the full extent of the facilitative interaction. Plant leaf temperature regulation is essential for photosynthesis, respiration, and water retention. Leaf temperature could also be influenced by facilitative interactions in spatially clumped plants. The goal of this study is to address the question: How does leaf surface temperature relate to neighbor density in alpine plant communities? I hypothesized that clu

Quantifying ethanol in bumble bee honey and Colorado rocky mountain wildflowers - S. Bustamante (2025)
Ethanol is a natural byproduct of yeast fermentation of plant sugars. In flowering plants, yeasts often form mutualistic relationships by inhabiting nectar, where they benefit from access to sugar and confer antimicrobial protection through the production of ethanol. Ethanol in nectar not only shapes microbial communities but may also influence pollinator behavior. Prior studies have shown that pollinators such as honey bees and Oriental hornets are attracted to or tolerant of ethanol despite its toxicity. However, little is known about the actual concentrations of ethanol naturally present in the dietary sources of sugar for bees, namely their honey (in the case of eusocial bees) and foraged floral nectar. This study quantified ethanol levels in the honey of eight commercial bumble bee colonies and the floral nectar of five native plant species in the Colorado Rocky Mountains: Mertensia ciliata, Ipomopsis aggregata, Corydalis caseana, Delphinium barbeyi, and Aconitum columbianum. By p

Quantifying physiological and behavioral differences in caddisfly larvae - C. Romo-Ornelas (2025)
The Mexican Cut Nature Preserve supports diverse populations of caddisflies (Limnephilus externus), whose larvae construct protective cases from environmental debris. Case morphology varies with ecological pressures, but gaps remain in understanding how intra- and interspecific interactions influence case size across larval development. This study quantified case size differences between permanent (high salamander density, HSD) and semi-permanent (low salamander density, LSD) ponds and assessed behavioral adaptations under controlled densities. Field surveys measured case sizes across larval instars via standardized net sweeps and photographic analysis. A semi-experimental design reared larvae from HSD and LSD sites at low (3 larvae/tank) and high (15 larvae/tank) densities to evaluate case construction and behavior. Contrary to predictions, larvae from LSD ponds constructed significantly larger cases across all instars (third: LSD 0.68±0.02 cm² vs HSD 0.52±0.03 cm², p<0.001; fifth: LS

Molecular diversity of dissolved organic matter reflects macroecological patterns in river networks - E. C. Freeman; M. K. Mudunuru; K. L. Feeser; E. A. McClure; R. Gonzalez-Pinzon; C. S. Ward; E. M. Bottos; S. Krause; J. Pena; Michelle Newcomer (Scientific Reports, 2025)

Modeling spatial distribution of snow water equivalent using transfer learning across mountainous basins - L. E. Halabi; Utkarsh Mital; Dipankar Dwivedi (Journal of Geophysical Research: Machine Learning and Computation, 2025)
Abstract Accurately estimating snow water equivalent (SWE) is crucial for understanding the impacts of climate change, urbanization, and population growth on water resources. High operational costs of lidar observations limit the frequency and coverage of SWE estimates at high spatial resolutions, leading to significant data gaps. We address this challenge with a transfer learning (TL) framework that leverages abundant SWE data from California to enhance predictions in Colorado, where data are scarce. From 2016 to 2019, the disparity in SWE data collection between these states was stark: 94 snowpack maps were recorded in California's Sierra Nevada versus only 12 in Colorado's Rocky Mountains. We hypothesized that geographic predictors (e.g., elevation and snowfall) would exhibit similar effects on SWE across these landscapes. By conducting an exploratory factor analysis, we validated this hypothesis and refined our TL model, which incorporated data based on 80 snowpack maps from Califo

Seven County Infrastructure Coalition v. Eagle County, Colorado - Cale Jaffe; Xiao Wang (SSRN Electronic Journal, 2025)

Celebrating Creation on the Colorado River - Kathleen Van Vlack; Richard W. Stoffle; Heather Lim; Simon Larsson (Heritage, 2025)
Ancient figures and symbols are carved into a high rock wall beside the Colorado River, just south of where a traditional Native American geotrail crosses the river near Moab, Utah, USA. Based on ethnographic interviews with tribal and pueblo representatives, the rock peckings identify an ancient ceremonial geosite, which, among other purposes, serves as a site for the Celebration of Creation. The interpretation of the site is situated within the geologically complex and ancient cultural heritage region composed of functionally interrelated nested geoscapes that surround the study area. The analysis is informed by ethnographic interviews from six U.S. federally funded studies that involved thirteen participating tribes and pueblos. The analysis is guided by an intellectual framework aligned with internationally recognized UNESCO heritage categories—namely, geosites, geotrails, and geoscapes. Grounded in these UNESCO heritage categories, the analysis advances new interpretive frameworks

Metagenome-assembled genomes for oligotrophic nitrifiers From a mountainous gravelbed floodplain - Anna N. Rasmussen; Bradley Tolar; John R. Bargar; Kristin Boye; Christopher Francis (Environmental Microbiology, 2025)
Riparian ﬂoodplains are important regions for biogeochemical cycling, including nitrogen. Here, we present MAGs from nitrifying microorganisms, including ammonia-oxidizing archaea (AOA) and comammox bacteria from Slate River (SR) ﬂoodplain sediments (Crested Bute, CO, US). Addionally, we explore MAGs from potenal nitrite-oxidizing bacteria (NOB) from the Nitrospirales. AOA diversity in SR is lower than observed in other western US ﬂoodplain sediments and Nitrosotalea-like lineages such as the genus TA-20 are the dominant AOA. No ammonia-oxidizing bacteria (AOB) MAGs were recovered. Microorganisms from the Palsa-1315 genus (clade B comammox) are the most abundant ammonia-oxidizers in SR ﬂoodplain sediments. Established NOB are conspicuously absent; however, we recovered MAGs from uncultured lineages of the NS-4 family (Nitrospirales) and Nitrospiraceae that we propose as putave NOB. Nitrite oxidaon may be carried out by organisms sister to established Nitrospira NOB lineages based o

Predicting the contribution of single trait evolution to rescuing a plant population from demographic impacts of climate change - Diane R. Campbell; J. M. Powers; Justin Kipness (Evolution Letters, 2025)
Evolutionary adaptation can allow a population to persist in the face of a new environmental challenge. With many populations now threatened by environmental change, it is important to understand whether this process of evolutionary rescue is feasible under natural conditions, yet work on this topic has been largely theoretical. We used unique long-term data to parameterize deterministic and stochastic models of the contribution of 1 trait to evolutionary rescue using field estimates for the subalpine plant Ipomopsis aggregata and hybrids with its close relative I. tenuituba. In the absence of evolution or plasticity, the 2 studied populations are projected to go locally extinct due to earlier snowmelt under climate change, which imposes drought conditions. Phenotypic selection on specific leaf area (SLA) was estimated in 12 years and multiple populations. Those data on selection and its environmental sensitivity to annual snowmelt timing in the spring were combined with previous data

Comparative life-cycle analyses reveal interacting climatic and biotic drivers of population responses to climate change - E. Ickin; Eva Conquet; B. Abrahms; S. D. Albon; Daniel T. Blumstein (PNAS Nexus, 2025)
Responses of natural populations to climate change are driven by how multiple climatic and biotic factors affect survival and reproduction, and ultimately shape population dynamics. Yet, despite substantial progress in synthesizing the sensitivity of populations to climatic variation, comparative studies still overlook such complex interactions among drivers that generate variation in population-level metrics. Here, we use a common framework to synthesize how the joint effects of climate and biotic drivers on different vital rates impact population change, using unique long-term data from 41 species, ranging from trees to primates. We show that simultaneous effects of multiple climatic drivers exacerbate population responses to climate change, especially for fast-lived species. However, accounting for density feedbacks under climate variation buffers the effects of climate change on population dynamics. In all species considered in our analyses, such interactions between climate and de

Multilevel selection on individual and group social behaviour in the wild - Conner S. Philson; J. G. A. Martin; Daniel T. Blumstein (Proceedings of the Royal Society B: Biological Sciences, 2025)
How phenotypes are shaped by multilevel selection-the theoretical framework proposing natural selection occurs at more than one level of biological organization-is a classic debate in biology. Though social behaviours are a common theoretical example for multilevel selection, it is unknown if and how multilevel selection acts on sociality in the wild. We studied the relative strength of multilevel selection on both individual behaviour and group social structure, quantified with social networks and 19 years of data from a wild, free-living mammal, the yellow-bellied marmot (Marmota flaviventer). Contextual analysis (exploring the impact of individual and group social phenotypes on individual fitness, relative to each other) revealed multilevel selection gradients in specific fitness and life history contexts, with selection for group social structure being just as strong, if not stronger, than individual social behaviour. We also found antagonistic multilevel selection gradients

Wild foundress queen bumble bees make numerous, short foraging trips and exhibit frequent nest failure: Insights from trap-nesting and RFID tracking - E. S. Gustilo; William Grover; S. Hollis Woodard (Ecology and Evolution, 2025)
The overwhelming majority of research on wild bumble bees has focused on the social colony stage. Nest-founding queens in the early season are difficult to study because incipient nests are challenging to find in the wild and the foundress queen flight period is very short relative to the entire nesting period. As a result, natural history information on foundress queens is exceedingly rare. New methodological approaches are needed to adequately study this elusive life stage. We trap-nested wild queen bumble bees in artificial nest boxes in Gothic, Colorado and used a custom-built radio frequency identification (RFID) system to contin- uously record queen foraging activity (inferred from entering and exiting the nest) for the majority of their spring flight periods. Foundress queens made frequent, short foraging trips, which tended to increase in duration over the course of the flight period. All queens who produced adult workers ceased foraging within approximately 1 week after wor

Improving plant DNA metabarcoding accuracy with ecological filters and Angiosperms353: Field and pollen microscopy validation - R. C. Benkendorf; E. J. Woodworth; Paul J. CaraDonna; Jane E. Ogilvie; S. Taddeo; J. B. Fant (Applications in Plant Sciences, 2025)

The short life of upvalley wind in a high-altitude valley in the Colorado Rocky Mountains - Bianca Adler; V. Caicedo; Brian Butterworth; Laura Bianco; Christopher Cox; Gijs de Boer; Ethan Gutmann; Janet Intrieri; T. Meyers; Joseph Sedlar; D. D. Turner; James Wilczak (Journal of Geophysical Research: Atmospheres, 2025)
Abstract Thermally driven upvalley (UV) wind in the upper East River Valley in the Colorado Rocky Mountains often unexpectedly stops in midmorning and reverses back to downvalley (DV) wind. We use a comprehensive observational data set for a nearly two‐year long period to analyze the wind system and boundary layer evolution in this high‐altitude valley and determine the reason for this early wind reversal. Days with short UV wind predominantly occur during the warm season when the valley floor is free of snow and the convective boundary layer (CBL) grows well above the height of the surrounding ridges. UV wind persists throughout the day only on a few days during the warm season. We link differences in valley wind evolution to wind direction at upper levels at and above ridge height and propose forced channeling mechanisms to describe coupling between valley and upper‐level wind when the CBL grows above ridge height. The frequency distribution of upper‐level wind direction is such that

Soil signals of key mechanisms driving greater protection of organic carbon under aspen compared to spruce forests in a North American montane ecosystem - L. Wang; S. A. Billings; Langlang Li; D. R. Hirmas; K. Johnson; D. Kerins; J. Pachon; Curtis A. Beutler; K. Jarecke; V. Varikuti; M. Unruh; H. Ajami; et al. (Biogeosciences, 2025)

Interpretable ensemble learning unveils main aerosol optical properties in predicting cloud condensation nuclei number concentration - Y. Wang; Y. Wang; C. Lu; B. Zhu; X. Yan; Y. Sun; J. Xu; J. Zhang; Z. Shen (NPJ Climate and Atmospheric Science, 2025)

A multi-year case study highlighting the influence of hydrological conditions on epidemic dynamics in a natural plant pathosystem - Keenan Duggal; Juliana Jiranek; Madison Machado; Peyton Smith; I. Miller; J. Metcalf (Oikos, 2025)
The scale of influence of hydrological and thermal conditions on disease remains uncertain for most wild plant pathosystems, thus restricting our ability to predict the impacts of climate change. Analysis of the spatiotemporal spread of a fungal rust pathogen throughout four naturally occurring flax populations over the course of five growing seasons reveals relationships between epidemic magnitude and snow cover, relative humidity and temperature, as well as an unexpectedly significant effect of severe drought on disease progression. These results indicate that climate change will likely disrupt wild plant epidemics, and points to a need for further epidemiological studies characterizing the effects of environmental conditions on population‐level disease dynamics in natural pathosystems.

Observing the effects of a nectar-inhabiting bacterium, Pantoea sp., and nectar robbing on male fitness in Ipomopsis aggregata - A. Litchfield (2025)
There is still much unknown about how microbes within flower nectars, specifically bacteria, impact pollinators. Hummingbirds use gustatory and visual cues to determine which flowers are most rewarding. The diversity in colonization of nectar-inhabiting microbes, such as bacteria, can alter the scent, taste, and chemical composition of a plant's nectar. Additionally, antagonistic nectar-robbing by insects can further alter the composition of nectar and affect a pollinator's perception of a floral reward. Despite this, there is very little research looking at the combined effect of nectar-inhabiting bacteria and nectar robbing on pollen movement and male flower fitness, within a natural system. We aim to observe this effect through inoculation of Pantoea sp. bacteria and application of a robbing treatment on Ipomopsis aggregata, a hummingbird- pollinated plant. We will track pollen donation using quantum dot fluorescent crystals. We expect to see lower male fitness and less pollen donat

The role of bedrock circulation depth and porosity in mountain streamflow response to prolonged drought - R. W. H. Carroll; Andrew H Manning; K. H. Williams (Geophysical Research Letters, 2025)
Abstract Quantitative understanding is lacking on how the depth of active groundwater circulation in bedrock affects mountain streamflow response to a multi‐year drought. We use an integrated hydrological model to explore the sensitivity of a variety of streamflow metrics to bedrock circulation depth and porosity under a plausible extreme drought scenario lasting up to 5 years. Endmember depth versus hydraulic conductivity relationships and porosity values for fractured crystalline rock are simulated. With drought, a deeper circulation system with higher drainable porosity more effectively buffers minimum flow and significantly limits perennial stream loss in comparison to a shallow circulation system. Streamflow buffering is accomplished through extensive groundwater storage loss. However, deeper circulation systems experience prolonged recovery from drought in comparison to storage‐limited shallow systems. Research highlights the importance of characterizing the deeper bedrock hydrog

Examining the effects of environmental variation on sociality in yellow-bellied marmots utilizing a within-individual centering approach - I. J. Thomson (2025)
The relationship between environmental variation and fitness has been well established. However, fitness may also be indirectly impacted by environmental variation through the modulation of social behavior. We aim to quantify the effects of environmental variation on sociality, specifically social relationships, with the knowledge that the subsequent changes in social behavior can have fitness consequences. Previous studies on sociality have often relied on annual analyses and, by focusing on a single year of social behaviors, have been unable to account for an individual’s lifetime patterns. A within-individual centering approach offers the ability to examine how sociality changes over an individual's lifetime and account for an individual's lifetime patterns. By utilizing the within-individual centering approach, we are able to utilize an individual’s lifetime average social position as a baseline to quantify the deviation in that individual's levels of social relationships each year

Increased temperature and CO2 induce plasticity and impose novel selection on plant traits - D. A. Denney; J. T. Anderson (Integrative and Comparative Biology, 2025)
Climate change is simultaneously increasing atmospheric carbon dioxide concentrations ([CO2]) and temperatures. We conducted a multi-factorial growth chamber experiment to examine how these climate change factors interact to influence the expression of ecologically relevant morphological and phenological traits, clines in these traits, and natural selection on these traits using diverse accessions of Boechera stricta (Brassicaceae) sourced from a broad elevational gradient in Colorado, USA. Plastic shifts in a key allocation trait (root mass fraction) in response to temperature accorded with the direction of selection via the probability of flowering, indicating that plasticity in this trait could be adaptive. However, plasticity in a foliar functional trait (leaf dry matter content) in response to temperature and [CO2] did not align with the direction of selection, indicating that plasticity could reduce fitness . For another ecologically important phenotype, selection favored resourc

Canopy structure modulates the sensitivity of subalpine forest stands to interannual snowpack and precipitation variability - Max Berkelhammer; G. Page; F. Zurek; C. Still; Mariah Carbone; W. Talavera; L. Hildebrand; J. Byron; K. Inthabandith; A. Kucinski; M. Carlson; K. Foss; et al. (Hydrology and Earth System Science, 2025)
Abstract. A declining spring snowpack is expected to have widespread effects on montane and subalpine forests in western North America and across the globe. The way that tree water demands respond to this change will have important impacts on forest health and downstream water subsidies. Here, we present data from a network of sap velocity sensors and xylem water isotope measurements from three common tree species (Picea engelmannii, Abies lasiocarpa and Populus tremuloides) across a hillslope transect in a subalpine watershed in the Upper Colorado River basin. We use these data to compare tree- and stand-level responses to the historically high spring snowpack but low summer rainfall of 2019 against the low spring snowpack but high summer rainfall amounts of 2021 and 2022. From the sap velocity data, we found that only 40 % of the trees showed an increase in cumulative transpiration in response to the large snowpack year (2019), illustrating the absence of a common response to interan

The sound of fear is heritable - Daniel T. Blumstein; N. Vu; M. N. Edic; L. Vo; J. G. A. Martin (Current Zoology, 2025)
The nonlinearity and fear hypothesis predicts that highly aroused vocal mammals and birds produce vocalizations (notably alarm calls and screams) which contain a variety of nonlinear phenomena (NLP). Such vocalizations often sound “noisy” because vocal production systems are over-blown when animals are highly aroused. While much is known about the conditions under which animals produce vocalizations containing NLP and how species respond to them, there is little research about the heritability of such behavioral traits. Using the quantitative genetic ani- mal model, we estimated the genetic basis of “noise” in alarm calls produced by females and found significant heritability in call entropy—our measure of the noisiness. About 9% of the variance in noisiness can be accounted for by genetic differences. Taken together, these findings suggest that the degree to which marmots produce noisy calls is modestly heritable and can be thus subject to further evolution via natural selection. Key

The effects of drought on wildflower size and seed set - G. Shirley (2025)
Climate change is leading to shifts in precipitation, including longer and more severe droughts. Perennial wildflowers in subalpine dry meadows are affected by current and potentially future droughts in the Rocky Mountains, and several species have shown phenotypic plasticity in response to environmental factors such as temperature, snowmelt date, and soil moisture. I compared the floral size and number of seeds between control and rainout-covered transects for the three plant species Delphinium nuttallianum, Eremogone (Arenaria) congesta, and Erigeron flagellaris. I found no significant difference between treatments in the flower size, nectar tube depth, or inflorescence height of any focal species. Seed set also did not vary significantly between rainout and control transects, and I did not find a correlation between floral size and seed set. These results do not indicate that the plants’ reproduction is negatively impacted by increased drought stress beyond that already present in t

Moss and vascular plant cover across elevational gradients in a changing alpine climate - E. Ristau (2025)
Mosses are foundational members of alpine plant communities but are often excluded from vegetation monitoring. In this study, I surveyed moss and vascular plant cover across five alpine ridges near Gothic, Colorado to understand how environmental variables shape moss abundance. I analyzed vegetation composition using data and related moss prevalence to elevation, slope, wetness, and climate trends. Moss presence was low across all sites, with most quadrats containing less than 5% moss cover. Wetness emerged as the strongest predictor of moss prevalence, with slope and elevation also influencing patterns in combination. Moss response to climate change was site-specific: rates of change in growing degree days and snowpack persistence over the past 2-3 decades showed inconsistent effects, with only one site (Crystal) showing a positive relationship between warming and moss prevalence. These findings suggest mosses occupy a narrow and shifting niche in alpine habitats, shaped by fine-scale

Nutrient niche dynamics among wild pollinators - J. A. Bain; Jane E. Ogilvie; William K. Petry; Paul J. CaraDonna (Proceedings of the Royal Society B: Biological Sciences, 2025)
Food underpins fitness and ecological interactions, yet how nutrient availability shapes species interactions in natural communities remains poorly understood. Most nutritional ecology research focuses on laboratory or single-species systems, limiting insight into how nutrient use and nutrient niche dynamics occur in complex, multispecies assemblages in the wild. We combined long-term plant-pollinator interaction data with pollen macronutrient analyses to examine how wild bumble bees exploit macronutrients and whether they occupy distinct nutrient niches. Pollen macronutrient composition varied across plant species and over the season, with protein-rich pollen peaking in spring and lipid- and carbohydrate-rich pollen increasing by late summer. Across this nutrient landscape, bumble bee species occupied two distinct macronutrient niches: one high in protein and low in lipid and carbohydrate, and the other lower in protein but moderate in lipid and carbohydrate. Nutrient niche partitioni

Is the propensity to alarm-call heritable and related across multiple contexts? - Daniel T. Blumstein; C. J. Velasquez; K. A. Adler; J. G. A. Martin (Animal Behaviour, 2025)
Alarm calling is an important antipredator behaviour by which individuals alert conspecifics and heterospecifics of possible danger and/or ward off potential predators. The propensity to utter calls may reflect the amount of risk an individual experiences and a variety of other internal and environmental factors that may be context and species specific. However, whether the propensity to utter alarm calls is heritable has not been studied. Using a quantitative genetic animal model, we estimated the heritability of alarm calling in yellow-bellied marmots, Marmota flaviventer . We found significant heritability in the propensity to utter naturally elicited alarm calls (0.06) and trap-elicited alarm calls when marmots were trapped (0.21). There was a small but significant genetic correlation between these traits (0.338). Together, these results show that the propensity to utter alarm calls is individually variable and context dependent and can evolve in response to natural selection. • We

Running on Empty: Climate Change and the Future of the Colorado River Basin - Mehdi Nemati; Daniel Crespo; Ariel Dinar; Paloma Avila (Scientia, 2025)
Amid growing pressures from climate change and population growth, water availability in the Colorado River Basin is declining while demand continues to rise. At the Water Dialogue Lab at the University of California, Riverside (UCR), Prof Mehdi Nemati and his colleagues, Dr Daniel Crespo, Prof Ariel Dinar, and Ms Paloma Avila from UCR’s School of Public Policy, along with Mr Zachary Frankel and Mr Nicholas Halberg from the Utah Rivers Council, have developed integrated models to assess changes in water availability, use, and associated economic values across the Basin. Their research evaluates the effects of climate change and policy interventions on both physical water supply and economic outcomes. Their findings highlight the need for adaptive planning, improved economic resilience, and policy reforms to ensure long-term sustainability in the region.

Phenology: An Integrative Environmental Science - David W. Inouye; F. E. Wielgolaski; F. E. Wielgolaski; David W. Inouye (2025)

A nectar-inhabiting bacterium may not influence female fitness in Ipomopsis aggregata - I. Garcia (2025)
Hummingbirds are known to select which floral resource to utilize based on visual and olfactory cues. The role that microbes play in mediating the mutualism between hummingbirds and flowers is mostly unexplored in the field of microbial and pollination ecology. Bee pollinators are known to be deterred by high concentration of bacterial nectar, and the same has been shown for hummingbirds but only in one highly controlled setting with artificial flowers. There is limited evidence on how bacterial nectar influences hummingbird pollination, especially in wild systems. We tested if the presence of Pantoea sp., a plant generalist bacterium, in floral nectar influences the female fitness of Ipomopsis aggregata, a hummingbird-pollinated wildflower. Plants were inoculated with sterile or bacterial nectar, at the end of the growing season, seed set, fruit set, and fly larval predation were calculated to test the effects of bacterial nectar on plant fitness. Floral and vegetative plants were als

Nonlinear phenomena in marmot alarm calls: a mechanism encoding fear? - Daniel T. Blumstein (Philosophical Transactions of the Royal Society B, 2025)
I review a case study of marmots that contributed to the empirical basis of the nonlinearity and fear hypothesis, which explains why certain nonlinear acoustic phenomena (NLP) are produced in extremely high-risk situations and communicate high urgency. In response to detecting predatory threats, yellow-bellied marmots (Marmota flaviventer) emit alarm calls and, in some situations, emit fear screams. Prior work on marmots has shown that call production is associated with the degree of risk the caller experiences and that they are individually distinctive. Receivers respond to calls and are sensitive to variation in caller reliability. Calls also contain nonlinear acoustic phenomena. Work has shown that socially isolated animals and those infected with Eimeria, an intestinal parasite, produced 'noisier' calls. However, animals that were likely under greater stress (as measured with faecal glucocorticoid metabolites) produced more structured and less noisy calls. The additio

Conditional syndromes: Effect of human disturbance and age on the correlation between flight initiation distance and vigilance in marmots - K. Uchida; I. DeVito; J. G. A. Martin; Daniel T. Blumstein (Behavioral Ecology and Sociobiology, 2025)
Behavioral syndromes—suites of correlated behaviors across different situations and contexts—are widespread and can have important ecological consequences because correlations between distinct behaviors shape how animals respond to changing environmental conditions and can limit behavioral plasticity. Behaviors such as vigilance, foraging, and explora- tion are correlated in many species and thus constitute a syndrome. Studying the structure of such syndromes is important to understand potential constraints on an animal’s behavioral response to the environment. Importantly, we know rela- tively little about antipredator behavioral syndromes and how their structure is associated with environmental conditions. Here, we estimated the correlation between two antipredator behaviors in yellow-bellied marmots (Marmota flaviventer): flight initiation distance (FID), which quantifies the flightiness of an animal in response to a potential predator and time allocation to vigilance while foraging

Brief for 30 Members of the U.S. House and Senate as Amici Curiae in Support of Respondents, Seven County Infrastructure Coalition v. Eagle County Colorado - Cale Jaffe (SSRN Electronic Journal, 2025)

Picky eater? How different environmental factors affect broad-tailed hummingbirds’ (Selasphorus platycercus) foraging patterns in the Rocky Mountains - T. Ngo (2025)
Plant and pollinator interactions are a form of mutualism requiring a careful balance between floral traits and pollinator behavior to maximize both pollination success and nectar consumption. This delicate relationship can result in detrimental effects on one party when the other shifts. Namely, global warming is causing phenological mismatches in many different ecosystems, where migratory species’ resources are impacted due to advanced flowering phenology. For example, many studies conducted at the Rocky Mountains Biological Laboratory (RMBL) in Gothic, Colorado have shown that the breeding season of Broad-tailed hummingbirds (Selasphorus platycercus) is shortened due to advanced blooming of early season species and no extension in late species’ blooming period. Moreover, climate change can affect environmental patterns like temperature, snowmelt timing or precipitation, which can alter resource availability for the hummingbirds within their breeding season. In this study, I analyzed

Reimagining river governance: Insights from the Colorado river crisis - Geraldo Wilson Fernandes; Geraldo Wilson Fernandes; Cássio Cardoso Pereira; Jessica Raty; Kevin Wheeler (BioScience, 2025)

Controls from above and below: Snow, soil, and steepness drive diverging trends of subsurface water and streamflow dynamics - D. Kerins; A. Knapp; F. S. Liu; V. D. Smykalov; M. P. Berzonsky; A. Vierbicher; K. Sadayappan; Brandy Stewart; E. D. Andrews; P. Sullivan; H. R. Barnard; J. Seibert; et al. (Hydrological Processes, 2025)

Society formation and maintenance in yellow-bellied marmots - Daniel T. Blumstein (Animal Behaviour, 2025)
Yellow-bellied marmots, Marmota flaviventer , are facultatively social and may form multigenerational societies, which are characterized by individuals sharing and defending space, possessing the ability to distinguish group members from outsiders and potentially persisting for many generations. I review some 63 years of continuous study that has revealed a number of insights about the adaptive value of sociality and societies. Because of their facultative sociality and because we have studied social behaviour and societies a variety of different of ways over the years, this social variation makes it difficult to make simple summary statements about society structure and formation. None the less, this variation may make them a good system in which to study incipient society formation. • Yellow-bellied marmots are facultatively social and at times live in societies. • Societies form when adult females recruit their daughters. • Males may interact with one or more societies. • I discuss

Genetic basis of an adaptive polymorphism controlling butterfly silver iridescence - L. Livraghi; J. J. Hanly; L. S. Loh; A. Henry; M. T. C. Keck; V. M. Shirey; C. C. Tsai; N. Yu; S. M. Van Bellegham; W. M. Roberts; C. L. Boggs; A. Martin (Current Biology, 2025)

Fitness costs and benefits of a non-native floral resource for subalpine solitary bees - Charlotte M. Cahill; Paul J. CaraDonna; J. R. K. Forrest (Oikos, 2025)
Organisms inhabiting seasonal environments must fit their life cycle into a limited time window while also synchronizing periods of resource consumption with timing of resource availability. Introduced non‐native species, which often differ in phenology from natives, can alter and expand the seasonal window of resource availability for native consumers, providing potential fitness benefits. However, if these non‐native resources are nutritionally unsuitable for native consumers, their presence could elicit foraging behaviour that proves maladaptive – i.e. they could act as an ecological trap. Here, we used multi‐year field observations and a laboratory experiment to investigate the impacts of a common non‐native plant species on two components of fitness in three solitary bee species (all specialist consumers of pollen from the plant family Asteraceae) native to the Colorado Rocky Mountains. First, we tested whether individual bees that collect pollen from the non‐native common dandeli

Adaptation and gene flow are insufficient to rescue a montane plant under climate change - J. T. Anderson; M. L. Demarche; D. A. Denney; Ian K Breckheimer; J. Santangelo; Susana M. Wadgymar (Science, 2025)
Climate change increasingly drives local population dynamics, shifts geographic distributions, and threatens persistence. Gene flow and rapid adaptation could rescue declining populations yet are seldom integrated into forecasts. We modeled eco-evolutionary dynamics under preindustrial, contemporary, and projected climates using up to 9 years of fitness data from 102,272 transplants (115 source populations) of Boechera stricta in five common gardens. Climate change endangers locally adapted populations and reduces genotypic variation in long-term population growth rate, suggesting limited adaptive potential. Upslope migration could stabilize high-elevation populations and preserve low-elevation ecotypes, but unassisted gene flow modeled with genomic data is too spatially restricted. Species distribution models failed to capture current dynamics and likely overestimate persistence under intermediate emissions scenarios, highlighting the importance of modeling evolutionary process

Functional morphology of pollen capture in Syrphid flies (Diptera syrphidae): The effects of pile density and body region - J. Devora (2025)
This paper will focus on Syrphidae, an understudied but potentially impactful pollinator. Specifically, I will investigate how the density of the pile (hair) affects the amount of pollen grains carried. This research has the potential to significantly contribute to the field of entomology, as it addresses the controversy about the efficiency of Syriphidae as pollinators, especially in the context of the global decline of primary pollinators such as bees. To conduct this, I will gather Syrphids using the established protocol from the Berry Brosi Lab. The Syrphids will be microscopically examined to determine their pile density and the number of pollen grains present. I expect that as the pili are more dense, more pollen grains will be gathered by a Syrphid fly. Additionally, I will be examining six body parts and comparing the differences in the amount of pollen grains they can carry. I expect essential body parts for pollination, such as the face and ventral thorax, will contain more p

The effect of changing floral density on pollinator networks in a subalpine meadow environment - R. Jewett (2025)
Plant-pollinator networks shape the populations of flowering plants across the world. Ecosystems face increasing challenges that decrease floral density and threaten to restructure plant-pollinator networks. The responses of these networks will play a critical role in the fates of plant species, because pollinator foraging decisions are made in the context of a multispecies floral community. Pollinators make foraging decisions to optimize the foraging cost/benefit ratio based on factors including energy expended and gained. The loss of a single generalist plant species has been observed to disproportionately impact the pollinator network, decreasing visitation rates to surrounding plants. However, it is unknown how the concurrent decline of multiple flower species might affect the pollinator community and network. Understanding the impact of floral density on the pollinator network is critical for predicting the effects of ecosystem change. We applied clipping treatments to thirty-six

Visitors to Red-Naped Sapsucker sap wells and the effectiveness of artificial wells - S. M. Graham (2025)

Beyond static color: Exploring spatial and temporal dimensions of animal visual signals - A. Miller (2025)

The impacts of environmental change on plant and microbial communities: A turf transplant experiment in the Colorado Rocky Mountains - L. Seltzer (2025)
Climate change is altering both above-ground plant communities and below-ground microbial assemblages, yet their simultaneous responses to altered climate remain poorly understood. To address this, we conducted a whole-community transplant experiment across a 400-meter elevation gradient in the Colorado Rocky Mountains, examining how plant and soil fungal and bacterial/archaeal communities respond to experimental warming and cooling. Transplantation to warmer sites led to rapid, directional shifts of all groups, with compositions changing to resemble those at lower, warmer sites, and diverging from higher origin sites. Soil bacteria and archaea responded most strongly, followed by fungi and then plants, indicating W differing sensitivities. Variation in responses may lead to novel communities, potentially disrupting relationships that affect ecosystem resilience. In contrast, transplantation to cooler IE sites led to weaker, slower, and more variable responses, with limited evidence of

Hydrologic connectivity shapes watershed response to climate variability from local to global scales - K. Johnson (2025)
Gynodioecy is a mode of sex expression where male sterlie (hereafter female) plants and hermaphroditic plants coexist within a population. In order for the females to be maintained by natural selection, they must have experienced an increased fitness. Fitness is defined as the ability of genotype or phenotype to contribute genes to the pool of seeds for the next generation. Since females only transmit their genes through seed production, their inability to produce pollen has to be compensated for. Experimental evidence from a variety of gynodioecious species have not found the theoretically required fitness advantage for females. This is in part may be due to interactions of the plant with its local frequency and density and not the global population characteristics. Females in particular may become pollen limited as the density and frequency of hermaphrodites declines. I present the results of a study that examined the effect of hermaphrodite density and frequency at three spatial sca

Dimensions of difference: Multi-scale consequences of trait variation in bumble bees - J. L. Fitzgerald (2025)
Body size is arguably one of the most important traits influencing the physiology and ecology of animals. Shifts in animal body size have been observed in response to climate change, including in bumble bees (Bombus spp.). Bumble bee size shifts have occurred concurrently with the precipitous population declines of several species, which appear to be related, in part, to their size. Body size variation is central to the ecology of bumble bees, from their social organization to the pollination services they provide to plants. If bumble bee size is shifted or constrained, there may be consequences for the pollination services they provide and for our ability to predict their responses to global change. Yet, there are still many aspects of the breadth and role of bumble bee body size variation that require more study. To this end, we review the current evidence of the ecological drivers of size variation in bumble bees and the consequences of that variation on bumble bee fitness, foraging

Investigating KDP signatures inside and below the dendritic growth layer with W-band Doppler radar and in situ snowfall camera - A. Kotsche; A. Myagkov; L. von Terzi; Maximilian Maahn; V. Ettrichrätz; T. Vogl; A. Ryzhkov; P. Bukovic; D. Ori; Heike Kalesse-Los (Atmospheric Chemistry and Physics, 2025)

Evaluation of cloud height, optical thickness, and phase retrievals from the CHROMA algorithm applied to Sentinel-3 OLCI data - A. M. Sayer; B. Cairns; K. D. Knobelspiesse; L. Lelli; C. Rajapakshe; S. E. Giangrande; Gavin H. Thomas; D. Zhang (Atmospheric Measurement Techniques, 2025)

Best restoration practices: Do BDAs mimic inundation patterns of natural beaver dams? - A. Daniel (2025)
​ Watershed degradation in the Western United States is a continuing issue under climate change. The headwaters to the Colorado River in the Rocky Mountains are experiencing dryness, altered chemistry, and flashiness due to climate change. Management practices involving artificial beaver dams (BDAs) have been used to counteract these issues. Though well intentioned, lack of monitoring has led to a lack of understanding of how these BDAs are impacting streams. There are uncertainties of how inundation patterns behind BDAs will change in shape, width, depth, and sediment deposition after a beaver further engineers the dams. We sampled six BDA ponds and beaver-augmented BDA ponds to compare a variety of morphological characteristics related to hydrology The beaver-augmented BDA ponds were significantly deeper than the BDA ponds since continuous engineering on the dams allows for more water impoundment and therefore a deeper pond. The BDA ponds had lower surface areas than the beaver-augme

A Bayesian record linkage approach to applications in tree demography using overlapping LiDAR scans - Lane Drew; Andee Kaplan; Ian K Breckheimer (Annals of Applied Statistics, 2025)
In the information age, it has become increasingly common for data containing records about overlapping individuals to be distributed across multiple sources, making it necessary to identify which records refer to the same individual. The goal of record linkage is to estimate this unknown structure in the absence of a unique identifiable attribute. We introduce a Bayesian hierarchical record linkage model for spatial location data motivated by the estimation of individual specific growth-size curves for conifer species using data derived from overlapping LiDAR scans. Annual tree growth may be estimated dependent upon correctly identifying unique individuals across scans in the presence of noise. We formalize a two-stage modeling framework, connecting the record linkage model and a flexible downstream individual tree growth model, that provides robust uncertainty quantification and propagation through both stages of the modeling pipeline via an extension of the linkage-averaging approac

Warming disrupts plant–fungal endophyte symbiosis more severely in leaves than roots - Justin D. Edwards; Melanie R Kazenel; Y. Luo; J. S. Lynn; R. L. Mcculley; L.A. Souza; C. Young; Jennifer A. Rudgers; Stephanie N. Kivlin (Global Change Biology, 2025)
Disruptions to functionally important symbionts with global change will negatively impact plant fitness, with broader consequences for species' abundances, distribution, and community composition. Fungal endophytes that live inside plant leaves and roots could potentially mitigate plant heat stress from global warming. Conversely, disruptions of these symbioses could exacerbate the negative impacts of warming. To better understand the consistency and strength of warming-induced changes to fungal endophytes, we examined fungal leaf and root endophytes in three grassland warming experiments in the US ranging from 2 to 25 years and spanning 2000 km, 12°C of mean annual temperature, and 600 mm of precipitation. We found that experimental warming disrupted symbiosis between plants and fungal endophytes. Colonization of plant tissues by septate fungi decreased in response to warming by 90% in plant leaves and 35% in roots. Warming also reduced fungal diversity and changed community compositi

Riming-dependent snowfall rate and ice water content retrievals for W-band cloud radar - N. Maherndl; A. Battaglia; A. Kotsche; Maximilian Maahn (Atmospheric Measurement Techniques, 2025)

Observations of surface energy fluxes and meteorology in the seasonally snow-covered high-elevation East River watershed during SPLASH, 2021–2023 - Christopher Cox; Janet Intrieri; Brian Butterworth; Gijs de Boer; M. Kate Gallagher; J. Hamilton; Erik Hulm; T. Meyers; S. Morris; Jackson Osborn; P. O. G. Persson; Benjamin Schmatz; et al. (Earth System Science Data, 2025)

Colorado River Basin: conflict management under hydrologic stress and institutional gridlock - Neil S. Grigg (International Journal of River Basin Management, 2025)
In the Colorado River, hydrologic and legal conditions create difficulty in sharing water effectively and equitably during a deep 22-year drought. Demand outstrips supply, water entitlements are over-appropriated, and institutional arrangements are nearly gridlocked. The crisis poses challenges not experienced before, and these may worsen with climate change and warming. It threatens the water supplies of major cities like Los Angeles and Las Vegas, as well as critical agricultural regions in the U.S. The background began to unfold more than 100 years ago, prior to signing of the Colorado River Compact in 1922. The decade prior to 1922 was relatively wet, and the Compact made water allocations that are not sustainable. Institutional challenges are caused by the rigidity of the rules governing river operations and the complex array of stakeholder organizations and management authorities. Although a wet 2022-3 winter provided temporary and only incremental relief, without a hydrologic re

Foraging preferences of generalist Megachilidae - G. Churchland (2025)
Subalpine ecosystems are home to hundreds of species of wildflowers, many of which are endemic and very vulnerable to climate change. Megachilidae are a family of primarily solitary bees that are very efficient pollinators, making them crucial components of subalpine ecosystems. Some Megachilidae species are generalists, meaning they visit a wide variety of flower species, but their exact foraging preferences remain poorly understood. Since some flowers are more affected by climate change than others, understanding generalists’ flower preferences is necessary in predicting their responses to climate change, and in protecting subalpine ecosystems. In this research project I (1) collected pollen samples from generalist Megachilidae nests and analyzed the pollen composition under a microscope, (2) compared the floral abundance in nests with the floral abundance in intentionally placed transects, (3) analyzed any foraging difference across genera, specifically between Osmia and Hoplitis fu

Hidden features: How subsurface and landscape heterogeneity govern hydrologic connectivity and stream chemistry in a montane watershed - K. Johnson; K. H. Williams; J. N. Christensen; R. W. H. Carroll; Langlang Li; Curtis A. Beutler; K. Swift Bird; Wenming Dong; P. Sullivan (Hydrological Processes, 2025)
ABSTRACT Hydrologic connectivity is defined as the connection among stores of water within a watershed and controls the flux of water and solutes from the subsurface to the stream. Hydrologic connectivity is difficult to quantify because it is goverened by heterogeniety in subsurface storage and permeability and responds to seasonal changes in precipitation inputs and subsurface moisture conditions. How interannual climate variability impacts hydrologic connectivity, and thus stream flow generation and chemistry, remains unclear. Using a rare, four‐year synoptic stream chemistry dataset, we evaluated shifts in stream chemistry and stream flow source of Coal Creek, a montane, headwater tributary of the Upper Colorado River. We leveraged compositional principal component analysis and end‐member mixing to evaluate how seasonal and interannual variation in subsurface moisture conditions impacts stream chemistry. Overall, three main findings emerged from this work. First, three geochemicall

Measurement report: An investigation of the spatiotemporal variability in aerosols in the mountainous terrain of the upper Colorado River basin using SAIL-Net - L. D. Gibson; E. J. T. Levin; E. Emerson; N. Good; A. Hodshire; G. McMeeking; K. K. Patterson; B. Rainwater; T. Ramin; B. Swanson (Atmospheric Chemistry and Physics, 2025)
Abstract. In the western US and similar topographic regions across the world, precipitation in the mountains is crucial to local and downstream freshwater supplies. Atmospheric aerosols can impact clouds and precipitation by acting as cloud condensation nuclei (CCN) and ice-nucleating particles (INPs). Previous studies suggest that there is increased aerosol variability in these regions due to their complex terrain, but none of these studies have quantified the extent of this variability. In the fall of 2021, Handix Scientific contributed to the Surface Atmosphere Integrated Field Laboratory (SAIL), funded by the US Department of Energy (DOE) and situated in the East River watershed (ERW; Colorado, USA), by deploying SAIL-Net, a novel network of six aerosol measurement nodes spanning the horizontal and vertical domains of SAIL. The ERW is a topographically diverse region, meaning individual measurement sites can miss important observations of aerosol–cloud interactions. Each measuremen

The role of soil in regulating plant performance in Valeriana edulis - C. Boxwell (2025)
Climate change is currently shifting the ranges of plant species, and while climate-based variables trigger migration, sessile plants may reach an expansion limit due to variations in the characteristics of local soils. To better understand the effects of soil on plant performance, we paired 13 years of demographic data on Valeriana edulis with gridded and field-collected soil data, then built vital rate models with these soil covariates to determine their impact on plants across the life cycle. We found that average grain size was highly influential on the survival, flowering, and seed production rates of Valeriana edulis. Water holding capacity and pH had moderate effects on flowering, and nitrogen had no meaningful impact. By analyzing how individual soil characteristics the performance of Valeriana edulis across its life cycle, we can make informed predictions about the eventual fate of the species under new environmental regimes.

Salamanders impact on L. externus population densities - T. Kelley (2025)
The caddisfly L. externus has been observed to have a decline in population density over the summer months as the larvae develop. However this pattern has not been formally tested, so collecting population density data is important for future research and understanding changes in densities over time. At the Mexican Cut, L. externus is common prey to tiger salamanders which may impact the magnitude of the density decline. This leads us to the question: How does the population number of L. externus decline over time in ponds with and without salamander predation? My hypothesis is the L. externus population density will decline at a steeper rate in ponds with salamanders than those without salamanders. Eight ponds were sampled with four being salamander and the other half being non salamander. The results found were that in the salamander ponds there was a steeper slope but a higher abundance at the beginning and in the non salamander ponds there was still a slope but significantly, stati

Abiotic influences on continuous conifer forest structure across a subalpine watershed - H. Marshall Worsham; Haruko M. Wainwright; T. Powell; Nicola Falco; L. M. Kueppers (Remote Sensing of Environment, 2025)
Understanding the abiotic drivers of high-elevation forest physiognomy is essential for forecasting how mountain ecosystems will respond to emerging environmental pressures. Most prior studies of these relationships have relied on small samples of the full landscape, resulting in limited power to detect dominant covariates and their interactions. Here we report the first evaluation of abiotic influences on a complement of accurate, wall-to-wall estimates of conifer forest structure and composition at the watershed scale. In a subalpine conifer domain in the Colorado Rocky Mountains (USA), we developed a novel method for deriving stand structure metrics from waveform LiDAR data, which showed high fidelity with field inventory. We quantified the relationships between structural and compositional metrics and climate, topographic, edaphic, and geologic factors. Our results showed that peak snow water equivalent (SWE), snow disappearance rate, and elevation explained most of the variation i

Dispersal of the golden-mantled ground squirrel (Callospermophilus lateralis) - N. Nguyen; Caitlin P. Wells; D. H. Van Vuren (Journal of Mammalogy, 2025)
Dispersal is common in mammals and can have an important role in shaping demography, genetics, distribution, and social structure. Dispersal entails potential costs but also potential benefits, and the dispersal decision is thought to be conditional; the potential disperser assesses prospects for success at its current location and disperses to improve its fitness. However, the costs and benefits of dispersal, as well as factors influencing the dispersal decision, are not well known. We used trapping and observation to study dispersal in the Golden- mantled Ground Squirrel (Callospermophilus lateralis), a species for which dispersal is largely unknown. We characterized the dispersal process by evaluating dispersal timing and distance, assessed factors that might influence the dispersal decision, and analyzed the fitness cost of dispersal after settlement. We found that most dispersal occurred during the summer of birth, as is expected for a small-bodied sciurid. However, some squirrels

Climatic variation and risk assessment in a highly seasonal mammal - M. Sanchez; J. G. A. Martin; Daniel T. Blumstein (Current Zoology, 2025)
Climate change and its resulting effects on seasonality are known to alter a variety of animal behaviors including those related to foraging, phe- nology, and migration. Although many studies focus on the impacts of phenological changes on physiology or fitness enhancing behaviors, fewer have investigated the relationship between variation in weather and phenology on risk assessment. Fleeing from predators is an economic deci- sion that incurs costs and benefits. As environmental conditions change, animals may face additional stressors that affect their decision to flee and influence their ability to effectively assess risk. Flight initiation distance (FID)—the distance at which animals move away from threats—is often used to study risk assessment. FID varies due to both internal and external biotic and physical factors as well as anthropogenic activities. We asked whether variation in weather and phenology is associated with risk-taking in a population of yellow-bellied marmots (Marmo

The Ohio Mine, Ouray County, Colorado: A Famous Quartz Locality Revisited - Jasper Bertisen; Robert Stoufer (Rocks & Minerals, 2025)

Matrix diffusion controls mountain hillslope groundwater ages and inferred storage dynamics - Nicholas Thiros; E. R. Woodburn; William Payton Gardner; P. James Dennedy-Frank; K. H. Williams (Groundwater, 2025)
Groundwater age distributions provide fundamental insights on coupled water and biogeochemical processes in mountain watersheds. Field-based studies have found mixtures of young and old-aged groundwater in mountain catchments underlain by bedrock; yet, the processes that dictate these groundwater age distributions are poorly understood. In this work, we use the coupled ParFlow-CLM integrated hydrologic and EcoSLIM particle tracking models to simulate groundwater age distributions on a lower montane hillslope in the East River Watershed, Colorado (USA). We develop a convolution-based approach to propagate fracture-matrix diffusion processes to the EcoSLIM advection-dominated age distributions. We compare observed 3 H and 4 He concentrations from two groundwater wells against model predictions that have varying advective transport times and matrix diffusion magnitudes. Based on a Monte Carlo analysis that considers uncertain matrix and fracture parameters, we find that matrix diffusion i

Opportunistic short-term water uptake dynamics by subalpine trees observed via in situ water isotope measurements - Matthias Sprenger; Stefan Seeger; Max Berkelhammer; N. A. Bogie; Raymond J. Hess; W. Brown; S. Kuppel; J. Knighton (Water Resources Research, 2025)
Abstract Variations in tree water sources are important to understand in semi‐arid ecosystems because climatic shifts towards lower snowpack and increased drought affect water availability in subalpine forests of the western US. Here, we use daily in situ measurements of stable isotopes ( 2 H & 18 O) in soil and tree stem water, soil matric potential and sap flow to study tree water uptake dynamics. We instrumented three soil profiles down to 90 cm, as well as three aspen and engelmann spruce trees near Gothic, Colorado, in the East River watershed. We observed the fate of natural isotopic variations in rainfall, soil, and plants from June to October 2022, and in August 2023 we conducted a 2 H labeled irrigation experiment. Our observations showed that all studied aspen trees compensated for water scarcity in the shallow soil by shifting the dominant water source at 60(±20) cm to ⅔ of uptake from 90 cm within a few days of a dry period. Both species relied on snowmelt stored in the

How strong is Snow? Spatial correlations of snowpack load bearing capacity and micromechanics from NASA SnowEx SnowMicroPen Data at Grand Mesa, Colorado - Molly E. Tedesche; Aaron C. Meyer; Sergey N. Vecherin; Tate G. Meehan (Cold Regions Science and Technology, 2025)

Does rainfall or temperature influence antipredator vigilance in a hibernating mammal? - K. Bobb; K. A. Adler; J. G. A. Martin; Daniel T. Blumstein (Behavioral Ecology, 2025)

Sick and alone? Evaluating how immune response is associated with social network position in yellow-bellied marmots - B. Stup (2025)

Effects of experimental warming on floral scent, display and rewards in two subalpine herbs - C. A. Wu; J. M. Powers; D. Hopp; Diane R. Campbell (Annals of Botany, 2025)
Our results suggest that floral traits can show different levels of plasticity to temperature changes in subalpine environments, with potential effects on animal behaviours that help or hinder plant reproduction. They also illustrate the need for more long-term field warming studies, as shown by responses of floral volatiles in different ways to weeks of warming vs. temperature at the time of sampling.

Seasonality and albedo dependence of cloud radiative forcing in the Upper Colorado River Basin - William Rudisill; Daniel Feldman; Christopher Cox; L. D. Riihimaki; Joseph Sedlar (Journal of Geophysical Research: Atmospheres, 2025)
Abstract Mountains create and enhance their own clouds, which both scatter and absorb shortwave radiation from the sun and absorb and re‐emit land surface and atmospheric longwave radiation. However, the impacts of clouds on the surface radiation balance in high elevation snowy mountain terrain are poorly explored. In this study, we use data collected by the SAIL field campaign and partner organizations in the upper elevations (2,880 m.a.s.l) of the Upper Colorado River Basin (UCRB) over a 21‐month period from September 2021 to June 2023 to estimate Cloud Radiative Forcing (CRF) in the shortwave, longwave, and the net effect. Longwave warming effects dominate during the winter when snow albedos are high (0.8–0.9) and the background atmospheric precipitable water vapor is low (0.5 cm), yielding a maximum monthly average net CRF of +34.7 W·m −2 , meaning that clouds increase the net radiation relative to clear skies during this time period. The sign of net CRF switches in the warm season

Out of sight, out of mind: The role of carcass burial and maintenance in reducing competition in Nicrophorus investigator - K. Chamberlin (2025)
Competition for ephemeral resources like carrion is intense among necrophagous insects, particularly burying beetles (Nicrophorus spp.), where reproductive success is limited by access to carcasses. Burial and post-burial maintenance behaviors are hypothesized to reduce carcass detection by competitors through the suppression of volatile organic compounds (VOCs). I investigated the relative importance of burial and maintenance in reducing discovery of small vertebrate carcasses by other carrion beetles. In a field study in a montane meadow in Colorado, I established can-based enclosures containing Peromyscus maniculatus carcasses under three treatments: surface (unburied), N. investigator pairs allowed to bury carcasses, but then removed to prevent further maintenance, and -N. investigator pairs allowed to bury carcasses and continue maintenance behaviors. Carcasses were protected from direct intrusion but exposed to visiting insects via screened funnel traps. Over two trials of daily

An uphill grind for wild plant populations - Sally N. Aitken (Science, 2025)

Social security: individuals in socially reciprocal groups may perceive security from predators - Conner S. Philson; C. Klassen; K. Uchida; Daniel T. Blumstein (Behavioral Ecology, 2025)

The heritability of fear: decomposing sources of variation in marmot flight initiation distance - M. A. Scurka; J. G. A. Martin; Daniel T. Blumstein (Animal Behaviour, 2025)

Temperature and relative humidity effects on nectar quantity, nectar quality, and plant-pollinator interactions - E. Wheeler (2025)
Nectar plays a critical role in attracting pollinators, thereby facilitating pollination and the spread of pollen. Nectar traits like volume and sugar concentration are strongly influenced by environmental factors such as temperature and relative humidity. Yet, there is little understanding of how these environmental and biological variables combine to influence the ability for a plant to attract insect pollinators. This study examined how temperature and relative humidity influence nectar volume and sugar concentration, and how these factors, in turn, affect pollinator visitation rates. We conducted this research at three subalpine wildflower meadows in Gunnison County, Colorado, from July 2 to August 1, 2025. We surveyed plant-pollinator interactions, collected ambient temperature and relative humidity data, and examined nectar volume and sugar concentration. Using mixed effects models, we found that an increasing temperature significantly increased nectar volume but decreased sugar

Flying by night: Comparing nocturnal pollinator networks over time in the Colorado Rocky Mountains - Daria Syskine; C. L. Boggs (Ecological Entomology, 2025)
Abstract Where climate is seasonal, such as in high‐altitude ecosystems, the occurrence and activity patterns of insect pollinators may vary with the varying occurrence of floral resources. This high turnover of species occurrence and interactions may lead to changes in the structure and properties of plant–pollinator networks. Here, we systematically compared the properties of moth pollen‐transport networks in Colorado, USA, over the course of a season, and tested for a link between moth species specialisation and morphology. We predicted that network properties would change through the season as the abundance and diversity of available floral resources increased. We also predicted that there would be a link between moth specialisation and morphology, as moth proboscis length can restrict their ability to utilise different floral resources. We sampled moths for pollen over 9 weeks in June through August 2021. We then constructed pollen‐transport networks, and used mixed models to test

Relaxation of the leaf economics spectrum within and across quaking aspen Populus tremuloides genotypes - J. Rieksta; Bente J. Graae; K. Helsen; R. E. Kapas; R. Strimbeck; B. Blonder (Oikos, 2025)

Does pollination interact with the abiotic environment to affect plant reproduction? - I. B. Rodelius; Amy M. Iler (Annals of Botany, 2025)
Although we found some evidence for the effect of a biotic interaction depending on abiotic conditions, it was only for one aspect of reproduction in one species, and it was in an unexpected direction. Our work highlights interactions between the abiotic and biotic components of the environment as an area of further research for improving our understanding of how plant reproduction responds to global change.

Contrasting depth dependencies of plant root presence and mass across biomes underscore prolific root-regolith interactions - S. A. Billings; P. Sullivan; Langlang Li; D. R. Hirmas; J. B. Nippert; H. Ajami; Alejandro Flores; K. Singha (AGU Advances, 2025)

Responses to climate change – insights and limitations from herbaceous plant model species - N. J. Kooyers; J. T. Anderson; A. L. Angert; M. L. Avolio; Diane R. Campbell; M. Exposito-Alonso; T. E. Juenger; D. A. Moeller; J. R. Napier; S. N. Sheth (New Phytologist, 2025)

Prevalence and severity of Melampspora lini on Linum lewisii under early snowmelt conditions - W. Goetting (2025)
Plant-pathogen interactions act as a selective pressure on both parties involved. Changes in their environment can cause these relationships to shift in favor of either party. Subalpine ecosystems are experiencing increased drought, early snowmelt, and advancing phenology as a result of climate change. Snowmelt typically signals key life cycle events for subalpine plants. Linum lewisii is a perennial subalpine plant that is experiencing changes in phenology as snowmelt dates shift. Melampspora lini is a fungal parasite that relies on Linum lewisii for its entire life cycle. As the phenology of L. lewisii changes with early snowmelt, is it unclear how prevalence and severity of M. lini will change. There is the potential for negative impacts on both parties, so comparing infection to demographic metrics like size and reproductive success can help us understand how climate change will affect subalpine plants; both directly through life cycle changes, and indirectly through changing plant

Legacy effects and arbuscular mycorrhizal fungi of Linaria vulgaris invasion in Colorado and Illinois, USA - L. Novak; G. M. Mueller; L. M. Egerton-Warburton (Invasive Plant Science and Management, 2025)
Abstract Invasive plants’ ability to extend their range depends upon their local environments and both positive and negative interactions with native species. Interactions between invasive and native plants may be indirectly linked to the soil fungal community, which may enhance or suppress invasion through mutualism or parasitism. Many invasive plants preferentially select fungal communities or change soil chemistry to gain a competitive advantage, and such changes can remain even after the invader is removed, known as legacy effects. Yellow toadflax ( Linaria vulgaris Mill.) is an invasive forb that is aggressive in the western United States but is nonaggressive in the midwestern United States. We evaluated the relationship between soil abiotic properties, nitrogen (N) enrichment, arbuscular mycorrhizal fungal (AMF) community composition, and L. vulgaris invasion in aggressive (CO) and nonaggressive (IL) populations. We collected soil from uninvaded and invaded sites in Gothic, CO, a

Natural selection on floral volatiles and other traits can change with snowmelt timing and summer precipitation - J. M. Powers; H. M. Briggs; Diane R. Campbell (New Phytologist, 2025)
Climate change is disrupting floral traits that mediate mutualistic and antagonistic species interactions. Plastic responses of these traits to multiple shifting conditions may be adaptive, depending on natural selection in new environments. We manipulated snowmelt date over three seasons (3-11 d earlier) in factorial combination with growing-season precipitation (normal, halved, or doubled) to measure plastic responses of volatile emissions and other floral traits in Ipomopsis aggregata. We quantified how precipitation and early snowmelt affected selection on traits by seed predators and pollinators. Within years, floral emissions did not respond to precipitation treatments but shifted with snowmelt treatment depending on the year. Across 3 yr, emissions correlated with both precipitation and snowmelt date. These effects were driven by changes in soil moisture. Selection on several traits changed with earlier snowmelt or reduced precipitation, in some cases driven by predispersal seed

Quantifying the effect of petrogenic carbon on SOC turnover for two Rocky Mountain soils: when are petrogenic carbon corrections required? - E. H. Williams; C. R. Lawrence (Journal of Geophysical Research: Biogeosciences, 2025)

The Effect of Globalization on the Places of Summit County, Colorado - Lucas Gauthier (University of Colorado Honors Journal, 2025)
The movement of people, capital, and culture associated with increasing globalization has had a profound impact on shaping the places we inhabit, the cultures we interact with, and the ways we live. The development of Summit County, Colorado, represents one of the most profound landscape evolutions of the past 160 years. In less than two centuries, the forces of globalization developed an isolated area with limited agricultural potential, unruly topography, and an inhospitable climate into one of the most expensive and well-known tourist destinations in the United States (Blevins, 2023). The progression of this process underscores how the imposing force of globalism can reframe our understanding of place and, by extent, reinforce or challenge existing cultural, social, and ideological norms. By examining how the changing focus and intensity of globalization have been reflected in present and historic development paradigms in Summit County, Colorado, we can see the profound power of glo

The effects of natural sun exposure on the intensity and distribution of salamander biofluorescence - J. Chairez (2025)
Salamanders have been used in a variety of different experiments to determine the health of various ecosystems. Biofluorescence was recently studied in amphibians in a study done in 2020. Not much is known about all its functions, more studies are needed to fully understand how it works and how it can be affected by environmental factors. Learning more about the functions of salamander biofluorescence could lead to a greater understanding of how pollutants and human impacts can affect salamanders and the health of their ecosystems. This project aimed to focus on tiger salamander biofluorescence and how its distribution and intensity is affected by the exposure of natural sunlight. Unmarked, 2nd year larval salamanders were taken from a single diverse pond to control for any differences among the ponds. The larvae were exposed to three different light treatments being dark, dimmed, and light. Within these light treatments there were also two time treatments that were six and twelve days

Sensory cues and memory in Lepidopteran mud puddling behavior - F. von Wallmenich (2025)
​ Puddling is a form of supplemental feeding for nectivorous Lepidoptera to acquire necessary mineral nutrients, primarily sodium, that are otherwise absent from their nectar diets. For many species sodium is important for growth, nervous system function, and egg production. However, the mechanisms through which Lepidoptera locate puddling sites is unknown. I investigated three potential factors influencing puddling site selection: visual cues from landscape contrast, olfactory cues from bacterial volatiles, and memory. Knowing the factors that influence lepidopteran puddling site selection can help us better understand how they find the resources necessary to survive and reproduce, as well as provide insight to the learning and memory capacities of Lepidoptera. Landscape contrast had a significant effect on lepidopteran puddling site selection, with butterflies on average choosing spots lighter than the surrounding area. Temperature and shade also affected butterfly puddling, with but

Does pollination interact with the abiotic environment to affect plant reproduction? - I. B. Rodelius; Amy M. Iler; I. B. Rodelius; Amy M. Iler (Annals of Botany, 2025)
Although we found some evidence for the effect of a biotic interaction depending on abiotic conditions, it was only for one aspect of reproduction in one species, and it was in an unexpected direction. Our work highlights interactions between the abiotic and biotic components of the environment as an area of further research for improving our understanding of how plant reproduction responds to global change.

Phylogeny does not predict the outcome of heterospecific pollen–pistil interactions in a species-rich alpine plant community - R. Cohen; Asstan Cisse; James V. Jones; J. H. Williams; D. A. R. Eaton (American Journal of Botany, 2025)
Our results show that even in communities where HPT is common, pre-zygotic post-pollination mechanisms do not provide strong barriers to interspecific fertilization. HPT can result in the loss of ovules even between highly diverged plant species.

Impacts of earlier snowmelt on fruiting phenology and seed success of Rocky Mountain wildflowers - S. Andrewlavage (2025)
Phenology, or the timing of biological events, has been found to shift in response to changing climates and key environmental cues such as spring temperatures and snowmelt date. These phenological shifts have been observed to be particularly extreme in mid-to-high latitude alpine environments, like Rocky Mountain ecosystems, where a variety of spring wildflowers have already been observed to be changing their flowering phenology. While flowering has been extensively studied, fruiting phenology remains largely unexplored, despite this stage being arguably more telling of reproductive output as the culmination of successful flowering and pollination events. Understanding how mean fruiting time and duration are impacted by shifting environmental cues will be critical in understanding the effects of future climate change on wildflower reproduction and population. To more thoroughly understand exactly how these potential shifts in fruiting phenology may be impacting wildflower reproductive

Long-term measurements of ice nucleating particles at Atmospheric Radiation Measurement (ARM) sites worldwide - J. M. Creamean; C. C. Hume; M. Vazquez; Adam Theisen (Earth System Science Data, 2025)

Alpine plants of Mt. Baldy: modeling phenology and documenting biodiversity - Hillary Xu (2025)
Alpine ecosystems are disassembling and reassembling due to climate change. The phenology of alpine plants has shifted, but empirical evidence for how spatial clustering patterns could impact this shift is lacking. This study investigated the phenology of spatially clustered versus isolated alpine plants in the Colorado Rocky Mountains, using linear models that considered co-variables such as plant size, snowmelt timing, and topography. A total of three focal species (Senecio crassulus, Lupinus argenteus, and Ivesia gordonii) with ca. 20 individuals per species were surveyed twice-weekly throughout July and August of 2025. We found that different aspects of phenology were affected by different variables. In 1 general, phenology shifts earlier due to snowmelt timing and shifts later due to the clustering effect. Natural history observations of ant behavior and a survey of the surrounding plant community supplement the understanding of the long-term Mt. Baldy research site.

Is early life adversity associated with adult stress in a wild rodent? - A. Y. Kong; X. Ortiz Ross; Daniel T. Blumstein (Ecology and Evolution, 2025)
The period before sexual maturity is a sensitive life stage where most development and change occur. Studies in humans and other animals show that early adverse experiences contribute to poor health and survival. However, the mechanisms are still unclear. Some have found that early life adversity (ELA) can lead to elevated glucocorticoids later in life, dysregulate the stress re- sponse, and increase the impact of later stressors. However, most animal studies have focused on individual stressors. Protecting wild populations that are exposed to multiple stressors requires a better understanding of the physiological consequences of several co-occurring stressors. We used a cumulative adversity index (CAI) to ask whether early adverse experiences were as- sociated with increased levels of adult fecal glucocorticoid metabolites (FGM) in wild female yellow-bellied marmots (Marmota flaviventer). We found a significant interaction between adversity and elevation that explained variation in

37Slabs of White: Panoramic Whales and Photographic Guano in the Mid-Nineteenth Century - Conor Lauesen (2025)
This article explores both the content and meaning of

This House Is Not A Home: Navigating Latinx Women’s Survival in Mexico - Ana Larissa Soares Cruz (2024)
For generations, Latinx women have often been expected to uphold the expectations of

Diverse and unconventional methanogens, methanotrophs, and methylotrophs in metagenome-assembled genomes from subsurface sediments of the Slate River floodplain, Crested Butte, CO, USA - Anna N. Rasmussen; Bradley Tolar; John R. Bargar; Kristin Boye; Christopher Francis (mSystems, 2024)
We use metagenome-assembled genomes (MAGs) to understand single-carbon (C1) compound-cycling-particularly methane-cycling-microorganisms in montane riparian floodplain sediments. We generated 1,233 MAGs (>50% completeness and <10% contamination) from 50- to 150-cm depth below the sediment surface capturing the transition between oxic, unsaturated sediments and anoxic, saturated sediments in the Slate River (SR) floodplain (Crested Butte, CO, USA). We recovered genomes of putative methanogens, methanotrophs, and methylotrophs (n = 57). Methanogens, found only in deep, anoxic depths at SR, originate from three different clades (Methanoregulaceae, Methanotrichaceae, and Methanomassiliicoccales), each with a different methanogenesis pathway; putative methanotrophic MAGs originate from within the Archaea (Candidatus Methanoperedens) in anoxic depths and uncultured bacteria (Ca. Binatia) in oxic depths. Genomes for canonical aerobic methanotrophs wer

Hydrology outweighs temperature in driving production and export of dissolved carbon in a snowy mountain catchment - D. Kerins; K. Sadayappan; Wei Zhi; P. Sullivan; K. H. Williams; R. W. H. Carroll; H. R. Barnard; Matthias Sprenger; Wenming Dong; J. Perdrial; Langlang Li (Water Resources Research, 2024)
Abstract Terrestrial production and export of dissolved organic and inorganic carbon (DOC and DIC) to streams depends on water flow and biogeochemical processes in and beneath soils. Yet, understanding of these processes in a rapidly changing climate is limited. Using the watershed‐scale reactive‐transport model BioRT‐HBV and stream data from a snow‐dominated catchment in the Rockies, we show deeper groundwater flow averaged about 20% of annual discharge, rising to ∼35% in drier years. DOC and DIC production and export peaked during snowmelt and wet years, driven more by hydrology than temperature. DOC was primarily produced in shallow soils (1.94 ± 1.45 gC/m 2 /year), stored via sorption, and flushed out during snowmelt. Some DOC was recharged to and further consumed in the deeper subsurface via respiration (−0.27 ± 0.02 gC/m 2 /year), therefore reducing concentrations in deeper groundwater and stream DOC concentrations at low discharge. Consequently, DOC was primarily exported from t

Optimizing Field-linked simulations of dry season uptake and monsoon infiltration within an aspen-mixed conifer forest - Raymond J. Hess (2024)
Climate models forecast that headwater catchments in the western U.S. will undergo a reduction in snowpack, early season snowmelt, and increases in evapotranspiration. The resulting extended dry season will stress vegetation in mountainous watersheds throughout the Upper Colorado River Basin. We investigate infiltration patterns and root water uptake in response to dry season disturbances within the East River watershed in Colorado. To do this, we collected soil cores, measured matric potential and sap flow, and monitored tree xylem and soil for stable isotopes of water (2H, 18O) in two soil profiles to 90 cm depth (with three Engelmann spruce and three aspen trees instrumented, respectively). Sub-daily stable water isotope dynamics were analyzed between mid-June and late October of WY-22 using a cavity ring-down spectrometer. HYDRUS-1D was calibrated with both field measurements of matric potential and δ2H to simulate the ecosystem response to late summer dry spells and monsoonal rain

The Power of Playing with Genre: The Western Gothic Melodrama in Jane Campion’s The Power of the Dog (Netflix, 2021) - Hervé Mayer (SPIRE - Sciences Po Institutional REpository, 2024)
International audience

Effects of trophic phenological synchrony or dyssynchrony on maternal investment of a small herbivorous mammal (Callospermophilus lateralis) - E. Grimland (2024)

Investigating the role of climate on juvenile Golden-mantled ground squirrel (Callospermophilus lateralis) growth and behavior - K. Simmons (2024)
Changes to climate can have a variety of consequences on organisms across all taxa. Though we are seeing climate changes across the globe, these effects can often be greater in high-elevation regions. For mammals in these environments, climate change can alter phenology, survival, and reproduction. Increasing temperatures have also been found to affect body mass, though this has been inadequately explored. This study investigated the effects of climate on the body mass and behavior of a high-elevation, hibernating small mammal, the golden-mantled ground squirrel (Callospermophilus lateralis). We compared the temperature and precipitation faced during a critical two-week growth period in juvenile ground squirrels to daily growth rates to determine any effects of climatic conditions on development. Additionally, we monitored juvenile squirrel behavior to compare time spent above ground and foraging to the temperature during that time. We found that temperature does significantly negative

Variation of wasp behavior patterns and pollination behavior on Ligusticum porteri - S. Joseph Wright (2024)

What are parasitoid wasps visiting Helianthella quinquenervis targeting, and could they influence plant fitness and reproduction? - D. Esquivel (2024)

Estimating Local Abundance of Bombus Queens in Meadows of Rocky Mountains, Colorado, USA - M. Shaffer (2024)

Interpopulation variation and optimal mating in the perennial herb, Polemonium brandegeei - J. Poortvliet (2024)
Generalist pollinated plants receive pollination services from a wide range of animals, but pollinator effectiveness varies. More effective pollinators in generalist systems optimize pollen transfer by promoting outcrossing between more distant plants. This leads to increased pollinator mediated selection by these pollinators on floral traits and variation in pollinator abundance may therefore cause population genetic and phenotypic differentiation across the range of a species. However, variation may also be caused by plastic responses to variable environmental conditions. Here, I analyze the prevalence and potential causes of interpopulation variation as well as optimal mating distance in generalist pollinated Polemonium brandegeei. I compared morphology and floral scent (1) among four field populations and (2) between field and greenhouse grown plants sourced from the same populations. Populations varied in morphology and floral scent profile and the southernmost population was most

Coexistence in Burying Beetles: The Niche of Reproductive Temperatures - K. Muse (2024)
Coexistence among species can occur in a variety of ways through niche partitioning. Two major niche components for many organisms are temperature and soil moisture and variation in these may occur with habitat heterogeneity. Near Gothic, Colorado at the Rocky Mountain Biological Laboratory, there are two habitats that pose differences in temperature and soil moisture: aspen forests and montane meadows. Two burying beetles species co-occur in these habitats (Nicrophorus defodiens and Nicrophorus investigator) and overlap significantly in their activity periods, diet, and reproductive behaviors. Temperature and soil moisture impact beetle development, adult flight, burial behaviors, and survival. Larvae are subject to temperature changes, where high temperatures lead to fatality and low temperatures slow development. Adults are subject to high temperatures and desiccation both aboveground and belowground. Aspen forests and montane meadows provide habitat heterogeneity (differing tempera

How do Bombus appositus and Bombus bifarius worker tongue lengths vary within a season? - O. Schenker (2024)
Schenker 1 Intraspecific trait variation – the variation among individuals within the same species – is seen within all natural populations and strongly affects the dynamics of and interactions between populations, communities, and ecosystems. Individual trait variation fluctuates across space and time, and understanding these patterns can provide a fuller understanding of species ecology and their interactions. Here, we quantified the degree of variation in worker tongue (proboscis) length, across a season within two wild bumble bee species (Bombus appositus and Bombus bifarius) throughout the Colorado Rocky Mountains. Specifically, we examined how the mean and variation of worker tongue length changes within a season. First, we measured the proboscis length and intertegular distance (ITD) – a strong proxy of body size – of workers. Second, we created an allometric scaling slope between proboscis length and body size to produce a robust estimate of this relationship. Third, we applied

Social Security: Do Individuals in Tight-Knit Social Groups Perceive Greater Security? - C. Klassen (2024)
Antipredator behavior is influenced by many factors including group size. Group size effects are seen when animals in larger social groups allocate less time to antipredator vigilance while foraging, but group size alone does not capture the diversity and complexity of sociality and behavior. An individual’s ‘sense of security’, or their perception of predation risk, is also influenced by an individual’s social behavior, but it is unknown is whether a group’s social structure – the pattern of all social interactions in a group – could explain variation in an individual’s perceptions of security. Using time allocated to vigilance during foraging and flight initiation distance (FID) as two measures of an individual’s sense of security, we explored whether individual yellow-bellied marmot (Marmota flaviventer) in tightly connected social groups looked less while foraging and had shorter FIDs compared to individual marmots in less- connected social groups. Using linear mixed effect models,

Solitary bee genera differ in foraging activity timing and temperature; Evidence of a seasonal dietary shift in Hoplitis fulgida - J. Ives (2024)
Global warming, and exacerbated warming temperatures with humane activity, could impose novel conditions on the lives of many organisms. Of those, the behaviors and diets of solitary bees face adaptive stress as their optimal foraging conditions and preferred floral resources fluctuate. Trap nests make the perfect study system to investigate climatic consequences, because of their easily observable and accessible nature. Using this study system, we sought to answer two main questions: (1) How do foraging time of day and temperature differ among trap-nesting bee taxa? and (2) how does the pollen diet of Hoplitis fulgida vary seasonally? Trap nests and their hosts, particularly pertaining to the questions being asked here, have been largely understudied, despite the possibility for broad inference on the temporal, thermal, and spatial differences in inter- and intraspecific solitary bee behaviors. Previous work has been done on the foraging activity of Osmia, though these studies haven’t

Dissecting phenotypic variation in the montane forb, Boechera stricta - M. I. Jameel (2024)

Context dependence of warming induced shifts in montane soil microbial functions - Sydne Spinella; Aimee T Classen; Nathan J. Sanders; Jennie R McLaren (Functional Ecology, 2024)
Abstract High elevation and latitude ecosystems are experiencing high levels of anthropogenic atmospheric warming. Climate warming may directly change soil microbial activity and alter ecosystem carbon dynamics and productivity, but increasing evidence suggests these responses may depend on other biotic factors such as plant community composition and abiotic factors such as moisture. We examined how abiotic (warming) and biotic (presence of dominant plant species) factors interact to affect soil microbial processes. Our experiment deployed the independent and combined treatments of experimental warming and dominant plant species removal in a high and low elevation montane meadows. We analysed multiple soil microbial responses to warming and the presence of a dominant plant at three times throughout the growing season, including soil respiration, microbial metabolic functional diversity, microbial biomass carbon and nitrogen, and extracellular enzyme potential activity. Overall, there w

Stream water sourcing from high-elevation snowpack inferred from stable isotopes of water: a novel application of d-excess values - Matthias Sprenger; R. W. H. Carroll; David W. Marchetti; C. Bern; H. Beria; W. Brown; Alexander W. Newman; Curtis A. Beutler; K. H. Williams (Hydrology and Earth System Sciences, 2024)
Abstract. About 80 % of the precipitation at the Colorado River's headwaters is snow, and the resulting snowmelt-driven hydrograph is a crucial water source for about 40 million people. Snowmelt from alpine and subalpine snowpack contributes substantially to groundwater recharge and river flow. However, the dynamics of snowmelt progression are not well understood because observations of the high-elevation snowpack are difficult due to challenging access in complex mountainous terrain as well as the cost and labor intensity of currently available methods. We present a novel approach to infer the processes and dynamics of high-elevation snowmelt contributions predicated upon stable hydrogen and oxygen isotope ratios observed in streamflow. We show that deuterium-excess (d-excess) values of stream water could serve as a comparatively cost-effective proxy for a catchment-integrated signal of high-elevation snowmelt contributions to catchment runoff. We sampled stable hydrogen and oxygen is

Effects of Dissolved Oxygen & Iron II Concentration Fluxes in Beaver-Impacted Floodplains - W. Hoins (2024)

Elucidating the influence of a nectar yeast and nectar robbing on bumblebee foraging tactic constancy - H. Thomas (2024)
Animal pollination services are vital for plant reproduction, with approximately 90% of plant species benefitting from this mutualistic relationship. Nectar is one of the most common floral rewards offered by plants in exchange for pollination services. Similarly, nectar is vital for bumbles as they consume it for flight fuel and nourishment for larvae and their colonies. However, not all floral visitors are pollinators. A forager may choose to forage legitimately (pollinate) or may choose to forage illegitimately (nectar rob). Nectar robbers bypass anthers at the floral opening and collect nectar by chewing a hole on the nectar spur or finding a pre-existing hole. Nevertheless, it has been shown that foraging patterns can be influenced by microbial presence and community structure implying that the presence of nectar inhabiting microbes (NIMs) can influence floral visitors’ behavior. We investigate how Metschnikowia reukaufii plays a role within this relationship, looking to further u

Intraspecific body size variation across distributional moments reveals trait filtering processes - J. L. Fitzgerald; Jane E. Ogilvie; Paul J. CaraDonna (Journal of Animal Ecology, 2024)
Natural populations are composed of individuals that vary in their morphological traits, timing and interactions. The distribution of a trait can be described by several dimensions, or mathematical moments-mean, variance, skew and kurtosis. Shifts in the distribution of a trait across these moments in response to environmental variation can help to reveal which trait values are gained or lost, and consequently how trait filtering processes are altering populations. To examine the role and drivers of intraspecific variation within a trait filtering framework, we investigate variation in body size among five wild bumblebee species in the Colorado Rocky Mountains. First, we examine the relationships between environmental factors (climate and floral food resources) and body size distributions across bumblebee social castes to identify demographic responses to environmental variation. Next, we examine changes in the moments of trait distributions to reveal potential mechanisms behind intras

Firmicutes and Bacteroidetes contribute to mass gain variation in female obligate hibernators - S. Degregori; G. C. Johnson; P. H. Barber; Daniel T. Blumstein (Journal of Mammalogy, 2024)
Abstract Obtaining body condition is an important life history challenge that directly impacts individual fitness and is particularly important for hibernating animals, whose maintenance of adequate body fat and mass is essential for survival. It is well-documented that host-associated microorganisms play a vital role in animal physiology and behavior. Recent work demonstrates that gut microbes are associated with fat accumulation and obesity, particularly the phyla Firmicutes and Bacteroidetes. The focus of most microbiome studies has been on human health or involved lab-reared animals used as a model system. However, these microbes likely are important for individual fitness in wild populations and provide potential mechanistic insights into the adaptability and survival of wildlife. Here we tested whether symbiotic microorganisms within the phyla of Firmicutes and Bacteroidetes were associated with summer mass gain in an exceptionally well-studied wild population of yellow-bellied m

Timing of seasonal events is correlated with social network position in a wild mammal - Conner S. Philson; C. Bruebach; T. Bastian; Billy Barr; Daniel T. Blumstein (Behavioral Ecology and Sociobiology, 2024)
Across animal systems, abiotic environmental features, including timing of seasonal events and weather patterns, affect fitness. An individual’s degree of social integration also has fitness consequences, but we lack an understanding of how abiotic features relate to patterns of individual sociality. A deeper understanding of this relationship could be developed from studying systems where these two links with fitness have already been identified. We explored the relationship between individual social behavior and seasonal timing, seasonal length, and weather patterns. We used social network analysis on a sixteen-year dataset of a wild population of hibernating yellow-bellied marmots (Marmota flaviventer). We fit a series of generalized linear mixed models and found that longer growing seasons before winter hibernation and longer winters were associated with increased individual sociality in the following spring. However, later snowmelt was associated with decreased sociality that spri

Declining groundwater storage expected to amplify mountain streamflow reductions in a warmer world - R. W. H. Carroll; Richard Niswonger; Craig Ulrich; Charuleka Varadharajan; Erica R. Siirila-Woodburn; K. H. Williams (Nature Water, 2024)
Abstract Groundwater interactions with mountain streams are often simplified in model projections, potentially leading to inaccurate estimates of streamflow response to climate change. Here, using a high-resolution, integrated hydrological model extending 400 m into the subsurface, we find groundwater an important and stable source of historical streamflow in a mountainous watershed of the Colorado River. In a warmer climate, increased forest water use is predicted to reduce groundwater recharge resulting in groundwater storage loss. Losses are expected to be most severe during dry years and cannot recover to historical levels even during simulated wet periods. Groundwater depletion substantially reduces annual streamflow with intermittent conditions predicted when precipitation is low. Expanding results across the region suggests groundwater declines will be highest in the Colorado Headwater and Gunnison basins. Our research highlights the tight coupling of vegetation and groundwater

Costly calling: Marmots who alarm call at higher rates are less likely to survive the summer and live shorter lives - Daniel T. Blumstein; K. A. Adler; J. Uy (Current Zoology, 2024)
Emitting alarm calls may be costly, but few studies have asked whether calling increases a caller's risk of predation and survival. Since observing animals calling and being killed is relatively rare, we capitalized on over 24,000 h of observations of marmot colonies and asked whether variation in the rate that yellow-bellied marmots (Marmota flaviventer) alarm called was associated with the probability of summer mortality, a proxy for predation. Using a generalized mixed model that controlled for factors that influenced the likelihood of survival, we found that marmots who called at higher rates were substantially more likely to die over the summer. Because virtually all summer mortality is due to predation, these results suggest that calling is indeed costly for marmots. Additionally, the results from a Cox survival analysis showed that marmots that called more lived significantly shorter lives. Prior studies have shown that marmots reduce the risk by emitting calls only when

Recent Upper Colorado River Streamflow Declines Driven by Loss of Spring Precipitation - D. Hogan; Jessica D. Lundquist (Geophysical Research Letters, 2024)
Abstract Colorado River streamflow has decreased 19% since 2000. Spring (March‐April‐May) weather strongly influences Upper Colorado River streamflow because it controls not only water input but also when snow melts and how much energy is available for evaporation when soils are wettest. Since 2000, spring precipitation decreased by 14% on average across 26 unregulated headwater basins, but this decrease did not fully account for the reduced streamflow. In drier springs, increases in energy from reduced cloud cover, and lowered surface albedo from earlier snow disappearance, coincided with potential evapotranspiration (PET) increases of up to 10%. Combining spring precipitation decreases with PET increases accounted for 67% of the variance in post‐2000 streamflow deficits. Streamflow deficits were most substantial in lower elevation basins (<2,950 m), where snowmelt occurred earliest, and precipitation declines were largest. Refining seasonal spring precipitation forecasts is impera

The hole truth: why do bumble bees rob flowers more than once? - J. L. Bronstein; G. Davidowitz; E. Litchenberg; R. E. Irwin (Plants, 2024)
Primary nectar-robbers feed through holes they make in flowers, often bypassing the plant's reproductive organs in the process. In many robbed plants, multiple holes are made in a single flower. Why a flower should be robbed repeatedly is difficult to understand: a hole signals that a nectar forager has already fed, which would seem likely to predict low rewards. We tested three explanations for this pattern in Corydalis caseana (Fumariaceae), a bumble bee pollinated and robbed plant: (1) multiple holes appear only after all flowers have been robbed once; (2) individual foragers make multiple holes during single visits; and (3) it is more profitable for bees to rob older flowers, even if they have already been robbed. We tested these hypotheses from 2014 to 2016 in a Colorado, USA population using data on robbing rates over time, floral longevity, nectar accumulation in visited and unvisited flowers, and the accumulation of robbing holes across the life of flowers. Multiple hole

Biofluorescence as a Mechanism of Sexual Selection in Ambystoma mavortium nebulosum - S. von der Ohe (2024)
Biofluorescence, the re-emission of absorbed light at lower energy wavelengths, has been widely documented in marine organisms and recently observed in amphibians. This phenomenon, particularly in amphibians such as frogs, salamanders, and newts, suggests potential roles in ecological interactions, including communication, mate selection, and predator avoidance. Despite advancements, the functional role of biofluorescence, especially regarding sexual selection, remains unclear. This study investigated the role of biofluorescence in sexual selection among Arizona Tiger Salamanders (Ambystoma tigrinum nebulosum), focusing on its behavioral functions and implications for conservation at the Mexican Cut in Colorado over the summer of 2024. Using a series of controlled experiments, we examined salamander preferences for different colored light and biofluorescent versus non-biofluorescent potential mates under blue light exposure. Results from glow stick and blue light control experiments in

Local Adaptations and Fitness of Transplants in the Lewis Flax – Flax Rust Coevolutionary System - K. Moussaoui (2024)
Disease progresses differently in varying environments. In coevolutionary interactions, species that interact frequently may adapt to their environment and to each other in a process called local adaptation. However, there may be trade-offs between adapting to the environment and to a coevolving partner. We used the host–pathogen system of Lewis flax and its coevolved fungal pathogen, flax rust, to study how the environment mediates adaptation to locally common pathogens. To separate these environmental and genetic effects, we placed sibling seedlings in their home environments, in different environments of similar elevation, and in environments of different elevations, and compared disease resistance to the local flax rust spores at the test site. We predicted that: 1) regardless of genetic resistance, lower elevation populations would present with less disease on average than higher elevation populations because of inhibitory effects of temperature; and 2) that seedling transplants w

Seasonal controls on microbial depolymerization and oxidation of organic matter in floodplain soils - C. Anderson; Malak M. Tfaily; Rosalie K. Chu; Nikola Tolic; P. M. Fox; P. Nico; Scott Fendorf; Marco Keiluweit (Environmental Science & Technology, 2024)
Floodplain soils are vast reservoirs of organic carbon often attributed to anaerobic conditions that impose metabolic constraints on organic matter degradation. What remains elusive is how such metabolic constraints respond to dynamic flooding and drainage cycles characteristic of floodplain soils. Here we show that microbial depolymerization and respiration of organic compounds, two rate-limiting steps in decomposition, vary spatially and temporally with seasonal flooding of mountainous floodplain soils (Gothic, Colorado, USA). Combining metabolomics and -proteomics, we found a lower abundance of oxidative enzymes during flooding coincided with the accumulation of aromatic, high-molecular weight compounds, particularly in surface soils. In subsurface soils, we found that a lower oxidation state of carbon coincided with a greater abundance of chemically reduced, energetically less favorable low-molecular weight metabolites, irrespective of flooding condition. Our results suggest that s

The Fate of Burying Beetles and their Carcasses: Hardships, Competition and Environmental Factors - J. Cantu (2024)
Burying Beetles face both intraspecific and interspecific competition throughout the whole process of rearing a brood. Nicrophorus (burying beetles) are a well-studied genus that provides bi-parental care on the carcass resource that they bury for rearing their brood. Because carcasses are often rare, there is a threat of intruders that may take over the resource. Lab studies have shown a significant cost of intruders, and the roles that the adults play in defense. However, few studies have been done on intraspecific intrusion in the wild, or how these might be affected by developmental stage, carcass size, and habitat type. This research at RMBL can help provide further information on the factors that influence the reproductive success of N. investigator and N. defodiens. Overall, no successful intrusion happened in any of the experiments with 72 mice placed out across 2 experiments. Aspen habitat had the most successful reproduction with 7 total successful broods of larvae, five N.de

Fit or Unlit: using quantum dots to investigate the effects of a floricolous yeast and nectar robbing on male fitness in Ipomopsis aggregata - G. Thoresen (2024)
The interaction network between pollinators, plants, and the microbes that inhabit them is not yet widely understood. Most studies of floral microbes have focused on the role of nectar yeasts (e.g., Metschnikowia reukaufii) in the behavior of bumblebee pollinators and how they affect the fitness of plant subjects. However, little is known about the effects of these microbes on the hummingbird-pollinated wildflower Ipomopsis aggregata. We used a full factorial experimental design with two treatment levels: supplementation with sterile vs. M. reukaufii-inoculated nectar analogue and artificial nectar robbing vs. no nectar robbing. We used fluorescent quantum dots to quantify how these factors affected the dispersal of pollen grains from donor plants by comparing pollen donation across the four plant treatments. Our results suggest potential male fitness advantage on robbed plants, evidenced by significantly higher pollen donation from robbed donor plants to neighboring individuals, irres

Plant-Pollinator Interactions between Erigeron speciosus and Heterotheca villosa in Virginia Basin - J. Vanston (2024)
Vanston 2 Plant-pollinator communities are complex networks that are essential to the promotion of biodiversity and ecosystem health. Plant pollinator networks are sensitive to environmental change, and climate change poses a severe threat to the dynamics of these networks. It is important to examine the individual dynamics within these communities to understand how they will be affected by climate change and increasing global temperatures. The focus of this study is to compare the individual mutualistic plant-pollinator relationships of Erigeron speciosus and Heterotheca villosa, two species of Asteraceae, the Daisy flower family, in Virginia Basin, Gothic, CO. Although H. villosa was more abundant than E. speciosus, E. speciosus was more attractive to pollinators. Bombus seemed to prefer H. villosa, but more sampling should be done. E. speciosus is likely more attractive due to its larger surface area of disc flowers. Further research should continue network sampling at Virginia Basi

The Effects of Temperature and N:P Ratios on Didymo Algae Growth - I. MacDougall (2024)
Didymosphenia geminata (didymo) is a species of algae that is native to North America, but has been producing unprecedented blooms during the last several decades. Climate change and nitrogen deposition are two hypothesized drivers of this phenomenon. The purpose of this research project is to better understand the conditions that drive didymo algae blooms in the Colorado Rocky Mountains. We hypothesize that didymo blooms will be greatest at high temperatures and under high N:P ratio treatments. In order to test this hypothesis, we used an experimental stream side channel experiment along the East River at the Rocky Mountain Biological Laboratory. There were five different N:P ratio treatments (2, 8, 16, 32, 100) and three temperature treatments combined in a factorial design (5 x 3). This experimental design will help us determine the correlation between temperature and N:P ratio treatments on didymo algae blooms. There were two statistical tests that we used for our data analysis, wh

Relational River: Arizona v. Navajo Nation & the Colorado - Jason Anthony Robison (SSRN Electronic Journal, 2024)

Getting to the Root of It: Effects of Castilleja Root Hemiparasitism on Plant Community Structure and Function - A. Hastings (2024)

Reproductive ecology of Erigeron speciosus, a montane perennial herb: Evidence of self-incompatibility - D. D. Ingold; Paul J. CaraDonna; J. L. Dooley; Amy M. Iler (The Southwestern Naturalist, 2024)
Realizamos un experimento para determinar la biología reproductiva de Erigeron speciosus (Asteraceae), una hierba montano perenne que se extiende por el Oeste de Norteamérica. Polinización de E. speciosus fue manipulado para entender: (1) >cuál es el sistema de apareamiento para E. speciosus (cruzamiento vs. autofecundación)? (2) >Es E. speciosus autoincompatible? (3) >La distancia del donador de polen afecta el éxito de la reproducción? (4) >El éxito de la reproducción será limitada por la recepción de polen (i.e., limitación polínica)? Comparamos la producción de semillas y la viabilidad de semillas por cinco tratamientos de polinización: polinización ambiente (control), exclusión de polinización (flores embolsadas), autopolinización solamente, y dos tratamientos de cruzamiento (donadores de polen cercanos y lejanos). Encontramos que E. speciosus es por gran parte autoincompatible y depende en cruzamiento para su reproducción. Aun así, la reproducción no fue limitada por polen en el

Forest composition and structural controls on canopy snow interception in a Colorado watershed - Curtis A. Beutler (2024)
Globally and across the Western United States shifting climate regimes have the ability to propagate change throughout ecosystems and affect their associated hydrologic functions. In mountain regions, which serve as “water towers” for much of humanity, the complex interactions between vegetation and water are especially vulnerable to climate change as they are subject to both ecological and hydrological disturbances. Forests exhibit major controls on the hydrology of mountain systems, of which a primary mechanism is the interception of falling snow in forest canopies which can result in up to 50% of intercepted snow being lost back to the atmosphere through sublimation. Despite being an important driver of forest-snow interactions, scientific inquiry on canopy snow interception has been limited to small spatial scales and limited observations due to the difficult nature of measuring snow in forest canopies. We used Terrestrial Laser Scanning (TLS) to quantify interception rates and int

A tale of two catchments: causality analysis and isotope systematics reveal mountainous watershed traits that regulate the retention and release of nitrogen - Nicholas J. Bouskill; Michelle Newcomer; R. W. H. Carroll; Curtis A. Beutler; Markus Bill; W. Brown; M. Conrad; Wenming Dong; Nicola Falco; Taylor Maavara; Alexander W. Newman; Patrick O. Sorensen; et al. (JGR Biogeosciences, 2024)
Abstract Mountainous watersheds are characterized by variability in functional traits, including vegetation, topography, geology, and geomorphology, which determine nitrogen (N) retention, and release. Coal Creek and East River are two contrasting catchments within the Upper Colorado River Basin that differ markedly in total nitrate (NO 3 − ) export. The East River has a diverse vegetation cover, and sinuous floodplains, and is underlain by N‐rich marine shale. At 0.21 ± 0.14 kg ha −1 yr −1 , the East River exports ∼3.5 times more NO 3 − relative to the conifer‐dominated Coal Creek (0.06 ± 0.02 kg ha −1 yr −1 ). While this can partly be explained by the larger size of the East River, the distinct watershed traits of these two catchments imply different mechanisms controlling the aggregate N‐export signal. A causality analysis shows physical and biogenic processes were critical in determining NO 3 − export from the East River catchment. Stable isotope ratios of NO 3 − (δ 15 N NO3 and δ

Social security: Does social position influence flight initiation distance? - T. Szulanski; Conner S. Philson; T. Szulanski; K. Uchida; Daniel T. Blumstein (Behavioral Ecology, 2024)
A variety of factors can influence an individual’s antipredator behavior including their group size because simply being around conspecifics may reduce predation risk. Recent work has shown that it is not just being around others, but rather the specific social relationships that individuals have with others may also modulate perceptions of risk and explain variation in a variety of antipredator behaviors. We asked whether and how yellow-bellied marmots’ (Marmota flaviventer) position in their social network explains variation in flight initiation distance (FID). We examined the relationship of both direct and indirect measures of sociality and separated models by age and sex classes to isolate the relationships for individuals with different life histories. Following the “social security” hypothesis, we predicted that more socially connected individuals would have a lower FID. We found that the magnitude and direction to which sociality was associated with FID varied based on age and

Pollen chemical and mechanical defences restrict host-plant use by bees - S. Rivest; M. Muralidhar; Jessica R. K. Forrest (Proceedings of the Royal Society B, 2024)
Plants produce an array of chemical and mechanical defences that provide protection against many herbivores and pathogens. Putatively defensive compounds and structures can even occur in floral rewards: for example, the pollen of some plant taxa contains toxic compounds or possesses conspicuous spines. Yet little is known about whether pollen defences restrict host-plant use by bees. In other words, do bees, like other insect herbivores, tolerate the defences of their specific host plants while being harmed by non-host defences? To answer this question, we compared the effects of a chemical defence from Lupinus (Fabaceae) pollen and a putative mechanical defence (pollen spines) from Asteraceae pollen on larval survival of nine bee species in the tribe Osmiini (Megachilidae) varying in their pollen-host use. We found that both types of pollen defences reduce larval survival rate in some bee species. These detrimental effects were, however, mediated by host-plant associations, wit

Climate mediates the trade-offs associated with phenotypic plasticity in an amphibian polyphenism - M. A. Kirk; A. C. R. Lackey; K. E. Reider; Sean C. Thomas; H. H. Whiteman (Journal of Animal Ecology, 2024)
Polyphenisms occur when phenotypic plasticity produces morphologically distinct phenotypes from the same genotype. Plasticity is maintained through fitness trade-offs which are conferred to different phenotypes under specific environmental contexts. Predicting the impacts of contemporary climate change on phenotypic plasticity is critical for climate-sensitive animals like amphibians, but elucidating the selective pressures maintaining polyphenisms requires a framework to control for all mechanistic drivers of plasticity. Using a 32-year dataset documenting the larval and adult histories of 717 Arizona tiger salamanders (Ambystoma mavortium nebulosum), we determined how annual variation in climate and density dependence explained the maintenance of two distinct morphs (terrestrial metamorph vs. aquatic paedomorph) in a high-elevation polyphenism. The effects of climate and conspecific density on morph development were evaluated with piecewise structural equation models (SEM) to tease a

Ecosystem-size relationships of river populations and communities - A. R. McIntosh; H. S. Greig; H. J. Warburton; J. D. Tonkin; C. M. Febria (Trends in Ecology & Evolution, 2024)
Knowledge of ecosystem-size influences on river populations and communities is integral to the balancing of human and environmental needs for water. The multiple dimensions of dendritic river networks complicate understanding of ecosystem-size influences, but could be resolved by the development of scaling relationships. We highlight the importance of physical constraints limiting predator body sizes, movements, and population sizes in small rivers, and where river contraction limits space or creates stressful conditions affecting community stability and food webs. Investigations of the scaling and contingency of these processes will be insightful because of the underlying generality and scale independence of such relationships. Doing so will also pinpoint damaging water-management practices and identify which aspects of river size can be most usefully manipulated in river restoration.

Patterns of genetic variation and local adaptation of a native herbivore to a lethal invasive plant - Nitin Ravikanthachari; Rachel A Steward; C. L. Boggs (Molecular Ecology, 2024)
Understanding the evolutionary processes that influence fitness is critical to pre- dicting species' responses to selection. Interactions among evolutionary processes including gene flow, drift and the strength of selection can lead to either local adap- tation or maladaptation, especially in heterogenous landscapes. Populations experi- encing novel environments or resources are ideal for understanding the mechanisms underlying adaptation or maladaptation, specifically in locally co-evolved interac- tions. We used the interaction between a native herbivore that oviposits on a patchily distributed introduced plant that in turn causes significant mortality to the larvae to test for signatures of local adaptation in areas where the two co-occurred. We used whole-genome sequencing to explore population structure, patterns of gene flow and signatures of local adaptation. We found signatures of local adaptation in response to the introduced plant in the absence of strong population structure

Impacts of assisted migration: An introduced herbivore has short-term and long-term effects on its native host plant population - Nitin Ravikanthachari; L. L. Burch; Rachel Powell; Danielle Scott; Charlotte Wayne; K. Niitepold; R. H. Rosenberg; C. L. Boggs (Entomologia Experimentalis et Applicata, 2024)
Abstract Assisted migration consists of the introduction of a species to previously inhabited areas or to new suitable regions. Such introductions have been touted as a viable tool for conserving the earth's biodiversity. However, both the likely success of assisted migrations and the impacts on local communities are hotly debated. Empirical data on the local impacts of assisted migration are particularly lacking. We examined the short and long time‐scale effects of herbivory on Lonicera involucrata (Richards) Banks ex. Spreng (Caprifoliaceae) after an introduction of Euphydryas gillettii Barnes (Lepidoptera: Nymphalidae, Melitaeini) to Gunnison County, Colorado, USA, via an assisted migration in 1977. The plant is the primary larval host plant for the butterfly. We quantified plant seed production, plant survival, and population stage structure in two sets of observational experiments. We found that herbivory by E. gillettii increased L . involucrata reproduction on an annual time sca

Decomposing an elevational gradient in predation by insectivorous birds - L. S. Dean; C. Vazquez-Gonzalez; S. Hellwitz; Luis Abdala-Roberts; K. A. Mooney (Ecosphere, 2024)
Abstract Insectivorous birds have ecologically important effects on prey abundance, behavior, and evolution, and through top‐down control, birds indirectly reduce herbivory and promote plant growth. While several studies sought to characterize biogeographic patterns in top‐down control by birds, variation in bird predation along elevational gradients is not well characterized in terms of both its commonness and the mechanisms underlying such variation. Here, we characterized variation in bird predation along a 700‐m montane elevation gradient using artificial clay caterpillars, assessing the roles of variation in aridity, other elevational effects not associated with aridity (e.g., most notably growing season length), and bird abundance and diversity. Multivariate models revealed increasing attack rates with aridity (when controlling for the effects of elevation) and elevation (when controlling for aridity). Because aridity declines with elevation, elevational patterns were not detecta

Consequences of pollen defense compounds for pollinators and antagonists in a pollen rewarding plant - S. Rivest; Stephen T. Lee; Daniel Cook; Jessica R. K. Forrest (Ecology, 2024)
Plants produce an array of defensive compounds with toxic or deterrent effects on insect herbivores. Pollen can contain relatively high concentrations of such defense compounds, but the causes and consequences of this enigmatic phenomenon remain mostly unknown. These compounds could potentially protect pollen against antagonists but could also reduce flower attractiveness to pollinators. We combined field observations of the pollen-rewarding Lupinus argenteus with chemical analysis and laboratory assays to test three hypotheses for the presence of pollen defense compounds: (1) these compounds are the result of spillover from adjacent tissues, (2) they protect against pollen thieves, and (3) they act as antimicrobial compounds. We also tested whether pollen defense compounds affect pollinator behavior. We found a positive relationship between alkaloid concentrations in pollen and petals, supporting the idea that pollen defense compounds partly originate from spillover. However, pollen a

Latest Pleistocene glacial chronology and paleoclimate reconstruction for the East River watershed, Colorado, USA - Brendon Quirk; I. J. Larsen; A. J. Hidy (Quaternary Research, 2024)
Reconstructing Pleistocene glaciation timing and extent is vital for understanding paleoclimate. Whereas late Pleistocene glaciation has been studied extensively in western North American mountain ranges, the glacial history of the western Elk Range in Colorado remains understudied, particularly in the East River watershed, a site of intense scientific focus. Here we use cosmogenic nuclide exposure and depth–profile dating methods to determine the timing of glaciation in the East River watershed. We use glacier modeling to reconstruct paleoglacier extents and quantify past climate conditions. Our findings indicate that the East River glacier retreated from its maximum position approximately 17–18 ka, moving to recessional positions between 13 and 15 ka, before experiencing more substantial retreat to high-elevation cirques around 13 ka. Glacier modeling suggests that the maximum ice extents at 17–18 ka could have been sustained by temperature depressions of approximately −6.5°C compare

Cold-season precipitation sensitivity to microphysical parameterizations: hydrologic evaluations leveraging snow lidar datasets - William Rudisill; Alejandro Flores; H. P. Marshall; Erica R. Siirila-Woodburn; Daniel Feldman; Alan Rhoades; Zexuan Xu; A. Morales (Journal of Hydrometeorology, 2024)
Abstract Cloud microphysical processes are an important facet of atmospheric modeling, as they can control the initiation and rates of snowfall. Thus, parameterizations of these processes have important implications for modeling seasonal snow accumulation. We conduct experiments with the Weather Research and Forecasting (WRF V4.3.3) Model using three different microphysics parameterizations, including a sophisticated new scheme (ISHMAEL). Simulations are conducted for two cold seasons (2018 and 2019) centered on the Colorado Rockies’ ∼750-km 2 East River watershed. Precipitation efficiencies are quantified using a drying-ratio mass budget approach and point evaluations are performed against three NRCS SNOTEL stations. Precipitation and meteorological outputs from each are used to force a land surface model (Noah-MP) so that peak snow accumulation can be compared against airborne snow lidar products. We find that microphysical parameterization choice alone has a modest impact on total p

Extending the social cohesion hypothesis: is group social structure associated with dispersal in yellow-bellied marmots (Marmota flaviventer)? - S. Schneidman; Conner S. Philson; Daniel T. Blumstein (Current Zoology, 2024)
Dispersal is an important individual decision which may influence individual fitness as well as population viability. The social cohesion hypothesis posits more social individuals remain at home, which is supported by prior work across taxa. However, how the sociality and connectivity of the group an individual resides in-their group social structure-relates to dispersal decisions has not been explored. We extend the social cohesion hypothesis to predict individuals residing in more social groups would remain at home, and we quantified the affiliative and agonistic social network structure of female yellow-bellied marmots (Marmota flaviventer), a facultatively social ground-dwelling squirrel, where about half of all females disperse. Using mixed-effects models, we found no support for the hypothesis that affiliative group structure explained any variation in a marmot's decision to disperse. We did find marmots in groups with less agonistic centralization (around one or few indiv

Does current weather or seasonality influence antipredator vigilance in a hibernating mammal? - K. Bobb (2024)

Bee phenological distributions predicted by inferring vital rates - M. Stemkovski; A. Fife; R. Stuart; Pearse W.D. (The American Naturalist, 2024)
AbstractHow bees shift the timing of their seasonal activity (phenology) to track favorable conditions influences the degree to which bee foraging and flowering plant reproduction overlap. While bee phenology is known to shift due to interannual climatic variation and experimental temperature manipulation, the underlying causes of these shifts are poorly understood. Most studies of bee phenology have been phenomenological and have only examined shifts of point estimates, such as first appearance or peak timing. Such cross-sectional measures are convenient for analysis, but foraging activity is distributed across time, and pollination interactions are better described by overlap in phenological abundance curves. Here, we make simultaneous inferences about interannual shifts in bee phenology, emergence and senescence rates, population size, and the effect of floral abundance on observed bee abundance. We do this with a model of transition rates between life stages implemented in a hierar

Marmots could have the solution to a long-running debate in evolution - M. Le Page (New Scientist, 2024)

Old-Aged groundwater contributes to mountain hillslope hydrologic dynamics - Nicholas Thiros; Erica R. Siirila-Woodburn; Matthias Sprenger; K. H. Williams; P. James Dennedy-Frank; R. W. H. Carroll; William Payton Gardner (Journal of Hydrology, 2024)
Understanding connectivity between the soil and deeper bedrock groundwater is needed to accurately predict a watershed’s response to perturbation, such as drought. Yet, the bedrock groundwater dynamics in mountainous environments are typically under-constrained and excluded from watershed hydrologic models. Here, we investigate the role of groundwater characterized with decadal and longer water ages on the hydrologic and mass-transport processes within a steep snow-dominated mountain hillslope in the Central Rocky Mountains (USA). We quantify subsurface and surface water mass-balance, groundwater flowpaths, and age distributions using the ParFlow-CLM integrated hydrologic and EcoSLIM particle tracking models, which are compared to hydrometric and environmental tracer observations. An ensemble of models with varied soil and hydrogeologic parameters reproduces observed groundwater levels and century-scale mean ages inferred from environmental tracers. The numerical models suggest soil wa

Shifting groundwater fluxes in bedrock fractures: Evidence from stream water radon and water isotopes - K. Johnson; J. N. Christensen; William Payton Gardner; Matthias Sprenger; Langlang Li; K. H. Williams; R. W. H. Carroll; Nicholas Thiros; Curtis A. Beutler; Alexander W. Newman; P. Sullivan (Journal of Hydrology, 2024)

Sodium enriched nectar shapes plant–pollinator interactions in a subalpine meadow - Ethan VanValkenburg; T. Goncalves Souza; Nathan J. Sanders; Paul J. CaraDonna (Ecology and Evolution, 2024)
Many plants have evolved nutrient rewards to attract pollinators to flowers, but most research has focused on the sugar content of floral nectar resources. Concentrations of sodium in floral nectar (a micronutrient in low concentrations in nectar) can vary substantially both among and within co-occurring species. It is hypothesized that sodium concentrations in floral nectar might play an important and underappreciated role in plant-pollinator interactions, especially because many animals, including pollinators, are sodium limited in nature. Yet, the consequences of variation in sodium concentrations in floral nectar remain largely unexplored. Here, we investigate whether enriching floral nectar with sodium influences the composition, diversity, and frequency of plant-pollinator interactions. We experimentally enriched sodium concentrations in four plant species in a subalpine meadow in Colorado, USA. We found that flowers with sodium-enriched nectar received more visits from a greater

Model and remote-sensing-guided experimental design and hypothesis generation for monitoring snow-soil–plant interactions - Haruko M. Wainwright; Baptiste Dafflon; Erica R. Siirila-Woodburn; Nicola Falco; Yuxin Wu; Ian K Breckheimer; R. W. H. Carroll (Frontiers in Water, 2024)
In this study, we develop a machine-learning (ML)-enabled strategy for selecting hillslope-scale ecohydrological monitoring sites within snow-dominated mountainous watersheds, with a particular focus on snow-soil–plant interactions. Data layers rely on spatial data layers from both remote sensing and hydrological model simulations. Specifically, a Landsat-based foresummer drought sensitivity index is used to define the dependency of the annual peak plant productivity on the Palmer drought severity index in the early growing season. Hydrological simulations provide the spatiotemporal dynamics of near-surface soil moisture and snow depth. In this framework, a regression analysis identifies the key hydrological variables relevant to the spatial heterogeneity of drought sensitivity. We then apply unsupervised clustering to these key variables, using the Gaussian mixture model, to group hillslopes into several zones that have divergent relationships regarding soil moisture, snow dynamics, a

Hydrological control of rock carbon fluxes from shale weathering - Jiamin Wan; Tetsu Tokunaga; Curtis A. Beutler; Alexander W. Newman; Wenming Dong; Markus Bill; W. Brown; A. N. Henderson; Anh Phuong Tran; K. H. Williams (Nature Water, 2024)
Shale bedrocks hold Earth’s largest carbon inventory. Although water is recognized for cycling elements through terrestrial environments, understanding how hydrology controls ancient rock carbon (Crock) release is limited. Here we measured depth- and season-dependent subsurface water fluxes and pore-water and pore-gas geochemistry (including radiocarbon) over five vastly different water years along a hillslope. The data reveal that the maximum depth of annual water table oscillations determines the weathering depth. Seasonally varying subsurface water fluxes determine the export forms and rates of weathered Crock. Eighty percent of released Crock is emitted as CO2 to the atmosphere primarily during warmer and lower water table seasons and 20% of released Crock as bicarbonate exports mostly during months of snowmelt to the hydrosphere. Thus, the rates and forms of Crock weathering and export are clearly controlled by climate via hydrologic regulation of oxygen availability and subsurfac

Does Floral Nectar Depth Correlate With Pollinator Proboscis Length? - S. Bograd (2024)
Pollination is essential for maintaining global biodiversity and our world’s food supply. Climate change is causing inefficiencies in plant-pollinator networks, so understanding the factors that determine which pollinators visit which plants will be exceedingly important for a sustainable future. Our study examined the effects of floral nectar depth on visitor proboscis length in a dry subalpine meadow at the Rocky Mountain Biological Laboratory. We conducted 46.5 hours of pollinator observations in addition to using historic observations in the same plant-pollinator community and historic measurements on the floral nectar depths and pollinator proboscis length, to test if pollinator visitation was affected by size thresholds or size matching. We found that flowers with greater nectar depths were visited by pollinators with longer proboscis, and that the meadow’s pollinators tend to visit flowers which have similar nectar depths to their proboscis length. Our results suggest that size-

The effects of advanced plant phenology on herbivory and plant demography - K. Dawdy (2024)

Effects of water availability on expression of vegetative traits in Ipomopsis across space and time - L. Emanuel (2024)
In subalpine ecosystems, climate change has contributed to an earlier snowmelt as a result of warmer temperatures in the winter and spring. This shift may act to limit water availability for plant communities by prolonging the period between initial snowmelt and late-season monsoon rains, placing these systems at risk of more frequent and severe drought. The genus Ipomopsis—a perennial subalpine plant—has been the subject of a long-term study at RMBL examining the effects of climate change on phenotype. Previous research has identified several vegetative traits in the genus whose expression can vary based on environmental factors including snowmelt date and soil moisture. This project aims to examine how water availability, specifically soil moisture, affects the expression of vegetative traits in Ipomopsis using both spatial (2024 data) and long-term temporal comparisons. Four traits—trichome density, specific leaf area (SLA), leaf volumetric water content (VWC), and photosynthetic wa