Growing Greener: Putting Conservation Into Local Plans And Ordinances - Randall Arendt (Medical Entomology and Zoology, 1999)
Growing Greener is an illustrated workbook that presents a new look at designing subdivisions while preserving green space and creating open space networks. Randall Arendt explains how to design residential developments that maximize land conservation without reducing overall building density, thus avoiding the political and legal problems often associated with down-zoning.The author offers a three-pronged strategy for shaping growth around a community's special natural and cultural features, demonstrating ways of establishing or modifying the municipal comprehensive plan, zoning ordinance, and subdivision ordinance to include a strong conservation focus. Open space protection becomes the central organizing principle for new residential development, and the open space that is protected is laid out to form an interconnected system of protected lands running across a community.The book offers: detailed information on how to conduct a community resource inventory a four-step approach to d

Invertebrates in Freshwater Wetlands of North America - D. P. Batzer; R. B. Rader; S. A. Wissinger (1999)

The role of urine marking in the foraging behavior of least chipmunks - J. A. Devenport; J. A. Devenport; C. Kokesh (Animal Behaviour, 1999)

Division of labor and worker caste efficiency in the western thatching ant Formica obscuripes - C. Carter (1999)

Flower constancy, insect psychology, and plant evolution - L. Chittka; J. D. Thomson; Nickolas M. Waser (Naturwissenschaften, 1999)
The way in which floral parameters, such as interplant distances, nectar rewards, flower morphology, and floral color affect constancy is considered, and the implications of pollinator constancy for plant evolution are discussed.

Design and implementation of the Solar Analyst: an ArcView extension for modeling solar radiation at landscape scales - P. Fu; P. M. Rich (1999)

An Irvingtonian species of Brachylagus (Mammalia: Lagomorpha) from Porcupine Cave, Park County, Colorado - Colleen N Ramos (The Great Basin naturalist., 1999)
Abstkact. -Bracliijlaûs i.s ciiircntK a inonotNiiic Î'liu.s ol unct'itaiii oiitiiiis and known only from Iloloccne and late Raiicholabrean. A new species ot leporid is clescrii)ed from the early and middle Pleistocene (Irvinjt̂onian) deposits of Poreiipine Cave, Park CountN; Colorado. Stratified deposits of the Pit and the Velvet Room, 2 localities within Porcu-I)ine Cave, have been dated hiochronologieally and paleomagnetically from the middle Irvinjt̂onian and early to middle Iningtonian, respectively. Brachijla<>.u.s colorudoensis, sp. now, is characterized by its conserved p3 enamel jiatterns which are intermediate between B. idahoeusis and Hypohifius, and its size which is slightly larger than that of B. idahoeusis. This snggests a possible ancestral relationshiji between Ihjpolanus and Br(ichi/la<îis.

Comparison of the understory of an isolated stand of lodgepole pine, Pinus contorta, to the understory of an adjacent stand of Populus tremuloides and to a more extensive stand of P. - T. Gray; D. Nilson (1999)

Spatial genetic structure of Delphinium nuttallianum populations: inferences about gene flow - C. F. Williams; Nickolas M. Waser (Heredity, 1999)

Nectar-robbing bumble bees reduce the fitness of Ipomopsis aggregata (Polemoniaceae) - R. E. Irwin; Alison K. Brody (Ecology, 1999)

Nectar on Tap? The Nectar Secretion Schedules of Two Species of Penstemon - J. Blackwood (1999)

Zapus hudsonius in southern Colorado - C. Jones (Occasional papers - Museum, Texas Tech University, 1999)

Effect of competition for pollination on the ecology and evolution of a hummingbird-pollinated plant, Ipomopsis aggregata - C. M. Caruso (1999)

The Effects of Road Dust with Magnesium Chloride on the local Flora of the Rocky Mountain Biological Laboratory, Gothic, Colorado - R. Hackney (1999)

Fluctuating Asymmetry:Environmental causes in adult and larval tiger salamanders, Ambystoma tigrinum nebulosum - J. Boynton (1999)

Pre-dispersal seed predation by Hylemya sp. in a plant hybrid zone of Ipomopsis aggregata and I. tenuituba - M. Crawford (1999)

Three Harpellales that live in one species of aquatic chironomid larva - R. W. Lichtwardt; M. C. Williams (Mycologia, 1999)
Two new species of harpellid gut fungi, Smittium fecundum and Stachylina robusta, were found living in larvae of Psectrocladius sp. (Diptera: Chironomidae) in a high-altitude kettle pond in the Rocky Mountains of Colorado. A third species of Harpellales, Smittium mucronatum, previously known only from Psectrocladius sordidellus in southern France, was found co-inhabiting the hindguts of the Colorado Psectrocladius larvae. Several axenic isolates of S. fecundum were obtained.

Criteria determining behavioural responses to multiple predators by a stream mayfly - A. R. McIntosh; B. L. Peckarsky (Oikos, 1999)
McIntosh. A. R. and Peckarsky, B. L. 1999. Criteria determining behavioural responses to multiple predators by a stream mayfly - Oikos 85: 554-564. We investigated prey responses to multiple predators by observing drift and positioning of Buetis bicuudctrus (Ephemeroptera: Baetidae) nymphs in the presence of non-feeding brook trout (Salvelinusfontinalis chemical cues) and predatory stoneflies (Megtrrcj,s̃ignura with glued mouths). In experiments carried out in stream-side channels Baeti.ãntipredator behaviour differed markedly in response to each predator separately: they drifted away from stoneflies. and reduced exposure and drift levels in the presence of trout odour. When both predator cues were presented together the effect of stoneflies, which were observed more frequently at night. depended on the time of day and was modified by presence of fish odour. During the day Buetis responses to both predators were hierarchical as drift and the number on stone tops was reduced whenever

The effects of ungulate herbivory on phenology, pollination, and reproductive success in Ipomopsis aggregata - K. Sharaf (1999)

Bumblebee foraging responses to variation in floral scent and color in snapdragons (Antirrhinum: Scrophulariaceae) - E. Odell; Robert A. Raguso; K. N. Jones (American Midland Naturalist, 1999)
We examined the roles of floral scent and color in attracting bumblebees (Bombus spp.) to snapdragon flowers (Antirrhinum, Sonnet cultivar). Corolla color differences covaried with differences in floral scent emissions in two inbred lines of snapdragon. White-flowered plants emitted methyl cinnamate, a scent compound not produced by yellow flowered plants, but lacked methyl benzoate, one of the major floral volatiles of the yellow-flowered line. Qualitative scent differences between the two lines were eliminated by applying the complementary scent compounds to filter paper wicks placed within the corollas. Laboratory analyses were performed using gas chromatography-mass spectrometry to verify appropriate modification of floral scents by this method. Two randomized arrays of control and scent-augmented flowers were visited by freely-foraging bumblebees in subalpine meadows in Colorado. Overall, yellow-flowered plants received more pollinator visits and had more flowers foraged per plant

Invertebrates in Freshwater Wetlands of North America: Ecology and Management - S. A. Wissinger; L. J. Gallagher; A. Bohonak; W. Brown; H. H. Whiteman; S. A. Wissinger; S. A. Wissinger (1999)

The use of mark/recapture to measure worker number in the rock nesting species Formica neorufibaris - Ian Billick (Insectes Sociaux, 1999)

Delayed egg hatching and semivoltinism in the nearctic stonefly Megarcys signata (Plecoptera:Perlodidae) - B. W. Taylor; Craig R. Anderson; B. L. Peckarsky (Aquatic Insects, 1999)
Delayed egg hatching can influence the survival of aquatic insects by reducing exposure to competi- tors, predators, parasites, or unfavorable environmental conditions. We examined egg development in a Colorado population of the stonefly, Megarcys signata (Plecoptera: Perlodidae), whose larvae in- habit high altitude streams in the Rocky Mountains of western North America. Five-thousand ferti- lized eggs were collected from 40 different females and incubated in the East River, Gunnison County, Colorado, until late fall, at which time unhatched eggs were transported to incubation chambers in Ithaca, New York. We used three different combinations of photoperiod and temperature (10L:14D, 4°C; 10L:14D, 8°C; 8L:16D, 8°C) in an attempt to induce hatching. Eggs in the treatments with temperatures elevated above normal winter temperatures in the East River (8°C) began developing after 6 months, whereas eggs in the treatment most closely simulating natural stream conditions (4°C) did not hatch

Dispersal of the fairy shrimp Branchinecta coloradensis (Anostraca): Effects of hydroperiod and salamanders - A. Bohonak; H. H. Whiteman (Limnology and Oceanography, 1999)
The absence of fairy shrimp (Anostraca) from permanent ponds and lakes is hypothesized to be the result of vertebrate predation. However, hatching cues for anostracan diapausing eggs include factors associated with the filling of temporary pond basins, and desiccation often increases the fraction of eggs that hatch. Thus, it is possible that in some species, eggs dispersed to permanent habitats never hatch, and vertebrate predation is not the proximate factor limiting distributions. We experimentally transplanted live egg‐bearing females of the fairy shrimp Branchinecta coloradensis into permanent and temporary ponds in small chambers and allowed the chambers to overwinter in situ. There was no discernible effect of pond drying on hatching success (mean success = 50.9%). We also determined whether metamorphic salamanders (Ambystoma tigrinum nebulosum) could disperse viable fairy shrimp eggs by feeding on B. coloradensis in one pond and defecating in another. Hatching success for a sala

The ecological effects of nectar robbers, with an emphasis on the reproductive biology of Corydalis caseana - J. E. L. Maloof (1999)

Religious Art: Reflectors of Change in the Catholic Church in New Mexico, 1830–1910. - Shirley Sands (1999)
In 1846, the United States of America began a war with the Republic of Mexico. When it was over, one of the results was the acquisition of much of current California, Arizona, Nevada, Utah, southern Colorado and New Mexico. The region was occupied by Catholic Mexicans, a fact not lost on the American Catholic hierarchy. The result is the sending of a new religious administration and the founding of what would become the Archdiocese of Santa Fe. The clergy sent were French with French notions of civilization, culture, and proper Catholic theology. These views and notions were contrary to those held by the Spanish-speaking population of the region and a struggle began. By using the religious art of Jesus and the Virgin Mary, and secondarily the architecture, found in several sacred sites, in a number of different locations, the depth of French clerical influence is measured from the years 1830 through 1910. The iconography of the subjects is examined as well as the forms of the art, wher

Experimental studies of long distance pollen-mediated gene flow in Delphinium nelsonii - B. Schulke (1999)

Effects of Local Density on Pollination and Reproduction in Delphinium nuttallianum and Aconitum columbianum (Ranunculaceae) - M. Bosch; Nickolas M. Waser (American Journal of Botany, 1999)
Plant populations vary in density both naturally and as a consequence of anthropogenic impacts. Density in turn can influence pollination by animals. For example, plants in dense populations might enjoy more frequent visitation if pollinators forage most efficiently in such populations. We explored effects of plant density on pollination and seed set in the larkspur Delphinium nuttallianum and monkshood Aconitum columbianum. At our site in the Colorado Rocky Mountains, flowers of D. nuttallianum are pollinated primarily by queen bumble bees, solitary bees, and hummingbirds, whereas those of A. columbianum are pollinated primarily by queen and worker bumble bees. We found that the quantity of pollination service to both species (pollinator visitation rate and pollen deposition) was at best weakly related to density. In contrast, seed set declined by approximately one‐third in sparse populations relative to nearby dense populations. This decline may stem from the receipt of low‐quality p

Evolution of sociality in marmots - Kenneth B. Armitage (Journal of Mammalogy, 1999)
The 14 species of marmots (Marmotd) can be placed in one of four social systems: solitary; female kin matriline; adult male with two females and immature offspring; and a family group consisting of a territorial pair, subordinate adults, and immature offspring. Body size and hibernation are two critical features of marmot biology from which sociality evolves. The high correlation (r = 0.91) between immergence mass and mass loss suggests that species are heavier because they require more mass to survive the hibernation period. Marmots increase mass either by having a larger frame or by increasing the amount of mass per frame. Emergence and immergence mass are linearly related to body length; but change in mass is curvilinearly related to body length: large species use relatively more mass. An analysis of mass:length ratios reveals that species with a relatively high immergence mass use considerable mass during the hibernation period whereas spec

Cooperative breeding in marmots - Daniel T. Blumstein; Kenneth B. Armitage (Oikos, 1999)
Whenever individuals live in stable social groups and not all individuals breed, group members may breed cooperatively. While well-documented in a variety of birds and mammals, there is some controversy over whether, and to what degree, sciurid rodents breed cooperatively. We identify cooperative breeding when: individuals delay dispersal beyond reproductive maturity, reproduction in mature individuals is suppressed, and when non-breeders provide alloparental care. In this paper we note that the 14 species of marmots (Marmota spp.), large ground-dwelling sciurid rodents found throughout the Northern Hemisphere, provide an excellent taxon in which to study the evolution of cooperative breeding. Marmot species fit none, some, or all of the attributes of cooperative breeding. Most interestingly, delayed dispersal and alloparental care may be de-coupled interspecifically, and possibly intraspecifically, making marmots an excellent taxon for additional study. Environmental harshness increas

The effect of experimental ecosystem warming on CO2 fluxes in a montane meadow - S. R. Saleska; J. Harte; M. S. Torn (Global Change Biology, 1999)
AbstractClimatic change is predicted to alter rates of soil respiration and assimilation of carbon by plants. Net loss of carbon from ecosystems would form a positive feedback enhancing anthropogenic global warming. We tested the effect of increased heat input, one of the most certain impacts of global warming, on net ecosystem carbon exchange in a Rocky Mountain montane meadow. Overhead heaters were used to increase the radiative heat flux into plots spanning a moisture and vegetation gradient. We measured net whole‐ecosystem CO2 fluxes using a closed‐path chamber system, relatively nondisturbing bases, and a simple model to compensate for both slow chamber leaks and the CO2 concentration‐dependence of photosynthetic uptake, in 1993 and 1994. In 1994, we also measured soil respiration separately. The heating treatment altered the timing and magnitude of net carbon fluxes into the dry zone of the plots in 1993 (reducing uptake by ≈100 g carbon m–2), but had an undetectable effect on ca

Two new Harpellales living in Ephemeroptera nymphs in Colorado Rocky Mountain streams - M. C. Williams; R. W. Lichtwardt (Mycologia, 1999)
Two new species of harpellid gut fungi (Zygomycota: Trichomycetes) are described from the hindguts of mayfly nymphs inhabiting high altitude Rocky Mountain streams: the new genus and species Legeriosimilis tricaudata living in Ameletus sp. (Siphlonuridae), and the new species Glotzia coloradense from Baetis tricaudatus (Baetidae). Legeriomyces aenigmaticus is reported from a new site and a new ephemeropteran host, Ephemerella sp. (Ephemerellidae), and previously unknown zygospores are described.

Natural History of Diuraphis (Homoptera: Aphididae) Species Occurring in Western Colorado - Robert W. Hammon; Frank B. Peairs (SPIE eBooks, 1998)
Three species of Diuraphis in addition to the Russian wheat aphid, Diuraphis noxia (Mordvilko), occur in western Colorado. Diuraphis (Holcaphis) tritici (Gillette), the western wheat aphid, and Diuraphis nodulus (Richards) were collected near Meeker (Rio Blanco County) in 1990. Both species were found feeding in seed production fields of mountain brome, Bromus marginatus, and have required chemical control at times to avert economic damage. Diuraphis (H.) frequens Walker was found in 2 localities in 1990. It was found in all but 1 growing season since that time in the West Elk Wilderness (Gunnison County), feeding on blue wild rye, Elymus glaucus. Males and oviparae of all 3 species were collected in 1991. Eggs of D. (H.) tritici and D. nodulus were collected in the spring and again in the fall of 1992. Two species of parasitic Hymenoptera, and 2 species of hyperparasites were collected from D. (H.) tritici and</i

Ecological Feedbacks to Global Warming: Extending Results from Plot to Landscape Scale - J. Harte (1998)

Annotated checklist of the recent mammals of Colorado - Jennifer. Saldaña-DeLeon; C. Jones (Occasional papers - Museum, Texas Tech University, 1998)
Several significant works on the Recent mammals of Colorado have been published, including Armstrong et al. (1994) sum¬ marized information on distribution and ecology of bats.

The sublime in Rothko, Newman and Still - Cliff G. McMahon (St Andrews Research Repository (St Andrews Research Repository), 1998)
An important body of literature has accumulated (both primary and secondary sources) which necessitates that Rothko, Newman and Still be placed in the tradition of the sublime. In attempting this task, a background is established by a detailed summary of classical theory of the sublime in Longinus, Burke, Kant, and Nietzsche, followed by detailed summaries of major recent sublimist theory by Weiskel, Crowther, Lyotard, and Ferguson. Also, key ideas of Sartre and Jung are treated in order to round out the proper ideational context for a sublimicist analysis of these three painters. From this foundation, a working theory of the sublime is developed. Next, the painters’ crucial theoretic statement are analysed for their relevance to the sublime, and their programs and specific works are characterized in relation to theory of the sublime, and in relation to their treatments in criticism.
The last two chapters treat two crucial contexts in which Rothko, Newman and Still are situated:

River: One Man's Journey down the Colorado, Source to Sea - Carolyn Maddux; Colin Fletcher (The Antioch Review, 1998)

Epibiosis of Colacium on Daphnia - R. Bartlett; R. L. Willey (1998)

Behavioral ecology and conservation biology - D. H. Van Vuren (1998)

Oviposition variation among Pieris napi due to increasing glucosinolate levels in cruciferous hostplants - S. Sabin (1998)

Alpine vascular flora of Buffalo Peaks, Mosquito Range, Colorado, USA - R. Seagrist; K. J. Taylor (Madrono, 1998)

Food supplementation and its influence on sex ratios and body weights of Spermophilus lateralis in Gothic, Colorado - E. Wall (1998)

Hummingbird foraging at experimental patches of flowers: evidence for weak risk-aversion - Nickolas M. Waser; J. A. McRobert (Journal of Avian Biology, 1998)
Hummingbirds foraging for nectar in mountains of the western USA encounter spatially-variable rewards under energetically-demanding environmental conditions. Previous workers have found that hummingbirds respond quickly to the average quantity and quality of reward; in addition, one might expect a response to reward variance. To explore this possibility we observed free-flying hummingbirds visiting two arrays of the native plant Ipomopsis aggregata. All flowers in one array received a 1 lI aliquot of artificial nectar whereas every fifth flower in the other array received 5 stl. This yielded a mean nectar standing crop similar to that found in nature, and variances in standing crop that were only slightly more extreme than those in nature. Over 12 days we recorded 362 foraging bouts by male and female Broad-tailed Selasphorus platycercus and Rufous S. rufus Hummingbirds. The high-variance (HV) array received 8.9% fewer foraging bouts than the low-variance (LV) array, and this differenc

Alpine vascular flora of Hasley Basin, Elk Mountains, Colorado, USA - R. Seagrist; K. J. Taylor (Madrono, 1998)

A 32-year demography of yellow-bellied marmots (Marmota flaviventris) - O. A. Schwartz; Kenneth B. Armitage; D. H. Van Vuren (J Zool London, 1998)
Yellow-bellied marmots Marmota ¯aviventris in the East River Valley of Colorado were live-trapped and individually marked annually from 1962 through 1993. These pooled data were used to produce a demography and life table for these years. Females had signi®cantly better survivorship than males beyond the ®rst-year age class, and the sex ratio became progressively female biased. The major mortality factors of predation and unsuccessful hibernation acted evenly on all age classes as shown by the constant rates of survivorship. The rate of senescence indicated that the probability of mortality did not increase with age. Females produced litters from ages 2 to 10 years. Mean litter size was 4.1 and did not differ among age classes. The female generation length of 4.49 years was 2.4 times the life expectancy and the median survivorship. The net reproductive rate (Ro) was 0.67, yet the population did not continually decline; adjustments to these data increased Ro to 0.85. Reproductive values

Genetic population structure of the fairy shrimp Brachinecta coloradensis (Anostraca) in the Rocky Mountains of Colorado - A. Bohonak (Canadian Journal of Zoology, 1998)
Dispersal rates for freshwater invertebrates are often inferred from population genetic data. Although genetic approaches can indicate the amount of isolation in natural populations, departures from an equilibrium between drift and gene flow often lead to biased gene flow estimates. I investigated the genetic population structure of the pond-dwelling fairy shrimp Branchinecta coloradensis in the Rocky Mountains of Colorado, U.S.A., using allozymes. Glaciation in this area and the availability of direct dispersal estimates from previous work permit inferences regarding the relative impacts of history and contemporary gene flow on population structure. Hierarchical F statistics were used to quantify differentiation within and between valleys (thetaSV and thetaVT, respectively). Between valleys separated by 5-10 km, a high degree of differentiation (thetaVT = 0.77) corresponds to biologically reasonable gene flow estimates of 0.07 individuals per generation, although it is possible that t

Reproductive strategies of yellow-bellied marmots: energy conservation and differences between the sexes - Kenneth B. Armitage (Journal of Mammalogy, 1998)
Yellow-bellied marmots (Marmota jlaviventris) conserve maintenance energy by reducing resting metabolic rate, decreasing conductance, avoiding thermal stress, by an annual cycle of metabolism, and by reducing metabolic rate and conductance following the mid summer molt. Male reproductive strategies include successful dispersal and locating females, establishing a territory and shifting energy use to summer defense, becoming polygynous and including as many females as possible within the territory, spending more time aboveground, and hibernating in the area where females are present. The major female reproductive strategy is the fonnation of matrilines, which facilitates the acquisition of resources, increases reproductive output, and provides a reproductive competitive advantage. Females also share space and are amicable with close kin, are agonistic toward all other females, may suppress the reproduction of other females, including their daughters, and produce daughter-biased sex rati

Effects of snow-melt timing on three high altitude Potentilla (Rosaceae) species: growth, reproduction, and distribution - K. A. Stinson (1998)

Effects of size at metamorphosis on stonefly fecundity, longevity, and reproductive success - B. W. Taylor; Craig R. Anderson; B. L. Peckarsky (Oecologia, 1998)
The data suggest that selection pressures determining body size at metamorphosis may operate independently on males and females, resulting in evolution of sexual size dimorphism, protandry, and mating early in the adult stage.

Life history consequences of social complexity: a comparative study of ground-dwelling sciurids - Daniel T. Blumstein; Kenneth B. Armitage (Behavioral Ecology, 1998)

Is the foraging behavior of Castor canadensis optimal? - ERIC R. Allen; M. Bonilla (1998)

Endangered mutualisms: the conservaiton of plant-pollinator interactions - C. A. Kearns; David W. Inouye; Nickolas M. Waser (Annual Review of Ecology and Systematics, 1998)

Head and body size relationship in polymorphic tiger salamander larvae from Colorado - J. P. Sheen; H. H. Whiteman (Copeia, 1998)

Shifts in the altitudinal distribution of bumblebees near Gothic, Colorado - E. Long (1998)

An assessment of bat activity and insect abundance between three sub-alpine habitats in central Colorado - K. O'Brien (1998)

Aggregation as a cost reducing strategy for lycaenid larvae - A. H. Axen; N. E. Pierce (Behavavioral Ecology, 1998)

Comparison of Aquilegia coerulea and Urtica gracilis growing on and off talus - J. E. Smith (1998)

Effects of food supplementation on a population of golden-mantled ground squirrel, Spermophilus lateralis - Angela Wright (1998)

Variation in lifetime male fitness in Ipomopsis aggregata: tests of sex allocation theory - Diane R. Campbell (American Naturalist, 1998)

Effects of supplemental food on growth and mobility of the golden-mantled ground squirrel, Spermophilus lateralis - E. Yates-Doerr (1998)

Pollination, angiosperm speciation, and the nature of species boundaries - Nickolas M. Waser (Oikos, 1998)
Despite much recent research on pollination, we have amassed relatively little hard information about how animal pollinators contribute to angiosperm speciation and species distinctiveness. We usually assume that pollinators make important contributions by specializing on plant species and providing differences upon which plants specialize. But evidence for generalization in many plant-pollinator interactions calls this assumption into question. Generalization makes strong floral isolation unlikely during and after the speciation process, and is seen by some workers as problematical for a scenario of pollinator-mediated disruptive selection leading to species formation. The time is ripe to initiate several lines of further research. It will be valuable to characterize selection on plants more carefully at various spatial scales to understand whether different suites of pollinators can affect consistent selection in different directions on floral characteristics. Similarly, it will be v

Location, Structure, and Contents of Burrows of Spermophilus Lateralis and Tamias Minimus, Two Ground Dwelling Sciurids - K. J. Bihr; R. J. Smith (Southwestern Naturalist, 1998)

What plant ecologists can learn from zoology - Nickolas M. Waser; Mary V. Price (Perspectives in Plant Ecology, Evolution and Systematics, 1998)
How improved communication with zoology can enrich plant ecology is illustrated by some individual and collective actions that plant ecologists can take.

Trapline foraging by bumble bees: III. Temporal patterning of visits - N. M. Williams; J. D. Thomson (Behavioral Ecology, 1998)

Nectar Robbing in Ipomopsis aggregata: Effects on Pollinator Behavior and Plant Fitness - R. E. Irwin; Alison K. Brody (Oecologia, 1998)

Salinity Trends in Surface Waters of the Upper Colorado River Basin, Colorado - Nancy J. Bauch; Norman E. Spahr (Journal of Environmental Quality, 1998)
AbstractDissolved‐solids data collected in the Upper Colorado River Basin upstream from Cameo, Colorado, and in the Gunnison River Basin were analyzed for trends in flow‐adjusted dissolved‐solids concentrations and loads for water years 1970 to 1993, 1980 to 1993, and 1986 to 1993. Trend results for flow‐adjusted periodic dissolved‐solids concentrations for the Colorado River Basin upstream from Cameo, CO, generally were downward or no trend was indicated. Trends in flow‐adjusted monthly and annual dissolved‐solids loads primarily were downward or absent. These trend results partly agree with the downward trends reported by a previous investigation for the Colorado River near Cameo site. In the Gunnison River Basin, trends in flow‐adjusted dissolved‐solids concentrations and loads were not detected for more than one‐half of the site/analysis‐period combinations. Of the trends that were present, most indicated decreases in concentrations and loads rather than increases. In both the Colo

Empirical considerations on the stable age distribution - O. A. Schwartz; Kenneth B. Armitage (Oecologia Montana, 1998)

Differentiating the effects of origin and frequency in reciprocal transplant experiments used to test negative frequency-dependent selection hypotheses - B. A. Roy (Oecologia, 1998)
Contrary to expectations, clones at their site of origin had less disease, less herbivory, and higher fitness than foreign clones, suggesting that the number of sites and clones needed to thoroughly test the hypothesis of negative frequency-dependent selection in this system is very large.

Does insect abundance affect bat activity in three subalpine habitats? - N. Doerr (1998)

A study of the colonization of fallen aspen by decomposers over time after avalanche activity - T. Grahl (1998)

Paleoglacier reconstruction and late Pleistocene equilibrium-line altitudes, southern Sawatch Range, Colorado - Keith A. Brugger; B. S. Goldstein (1998)

Adaptive significance of flower color and inter-trait correlations in an Ipomopsis hybrid zone - E. J. Melendez-Ackerman; Diane R. Campbell (Evolution, 1998)

Multiple paternity in fruits of Ipomopsis aggregata (Polemoniaceae) - Diane R. Campbell (American Journal of Botany, 1998)
Two different mechanisms can result in multiple paternity within fruits: deposition of a mixed pollen load due to carryover of pollen from flower to flower and multiple pollinator visits in close succession. I investigated the extent of multiple paternity within fruits of Ipompsis aggregata containing from 2 to 14 seeds. A paternity analysis based on ten polymorphic isozyme markers revealed multiple paternity in a minimum of 68% (based on simple paternity exclusion) and up to 100% (based on identification of the most likely father) of the multiseeded fruits. The estimated number of fathers increased with the number of seeds in a fruit, with an average of four sires, and up to nine sires, represented in a single fruit. To explore whether this level of multiple paternity could be explained solely by simultaneous deposition of a mixed pollen load, I constructed a computer simulation model based on previous measurements of movement patterns and pollen carryover by the hummingbird pollinato

The effect of trout on the diversity, richness and abundance of the mayfly species - K. Lautenschlager (1998)

The variation in tree growth performance relative to a climate change along an elevation gradient - V. X. Vela (1998)

The effect of feeding supplement on time budgets in yellow-bellied marmots (Marmota flaviventris) - J. E. Smith (1998)

Phenotypic plasticity of a larval caddisfly along a predator-permanence gradient in subalpine wetlands - S. A. Lopez (1998)

Effects of experimental warming on plant reproductive phenology in a subalpine meadow - Mary V. Price; Nickolas M. Waser (Ecology, 1998)
Increasing “greenhouse” gases are predicted to warm the earth by several degrees Celsius during the coming century. At high elevations one likely result is a longer snow-free season, which will affect plant growth and reproduction. We studied flowering and fruiting of 10 angiosperm species in a subalpine meadow over 4 yr, focusing on plant responses to warming by overhead heaters. The 10 species reproduced in a predictable sequence during 3–4 mo between spring snowmelt and fall frosts. Experimental warming advanced the date of snowmelt by almost 1 wk on average, relative to controls, and similarly advanced the mean timing of plant reproduction. This phenological shift was entirely explained by earlier snowmelt in the case of six plant species that flowered early in the season, whereas four later-flowering species apparently responded to other cues. Experimental warming had no detectable effect on the duration of flowering and fruiting, even though natural conditions of early snowmelt w

Life histories and the strengths of species interactions: combining mortality, growth, and fecundity effects - M. A. McPeek; B. L. Peckarsky (Ecology, 1998)
Interactive effects of one species on another may simultaneously influence mortality, growth, and fecundity. To quantify the strength of an interaction between two species, we must therefore use techniques that integrate these various responses into estimates of overall effect. Demographic models of populations provide such a framework. Here we develop a demographic model describing the life history of a hemimetabolous insect to evaluate the relative importance of predator effects on mortality and growth of damselflies (Enallagma boreale) in fishless ponds and mayflies (Baetis bicaudatus) in trout streams. Previous experiments have shown that dragonfly predators in fishless ponds inflict direct mortality and cause reduced growth rates in Enallagma damselflies. Parameterization of the demographic model from these data show, however, that only the direct mortality effects of dragonflies should significantly influence damselfly population dynamics. This is because damselfly size at emerge

Estimation of selfing rate and inbreeding depression in gynodioecious Geranium richardsonii F. & T - K. O'Malley (1998)

Time allocation to behavior in marmots: a comparison of adults and juveniles - M. S. Swift (1998)

The daily behavior of Eutamias minimus in a town setting - S. Ochs (1998)

A comparison of bird diversity in aspen and coniferous tree stands at equal elevation - M. Ruehmann; A. F. Camfield (1998)

A survey of two vascular plant populations: one within and one outside of a turf of the moss Anlacomnium sp. - S. R. West (1998)

A test of the acoustic adaptation hypothesis in four species of marmots - J. C. Daniel; Daniel T. Blumstein (Animal Behavior, 1998)
The evidence did not support the acoustic adaptation hypothesis for these marmot species, and factors other than maximizing long-distance transmission through the environment may be important in the evolution of species-specific marmot alarm calls.

Time allocation to behavior in marmots: a comparison of adults and juveniles - M. S. Swift; A. Kocis (1998)

Sex-specific fitness payoffs in a facultatively paedomorphic population of the tiger salamander Ambystoma tigrinum nebulosum - Angela Wright (1998)

Dispersal and gene flow in freshwater invertebrates - A. Bohonak (1998)

Fitness and community consequences of avoiding multiple predators - B. L. Peckarsky; A. R. McIntosh (Oecologia, 1998)
This study demonstrates the importance of considering multiple predators when measuring direct sublethal effects of predators on prey fitness and indirect effects on lower trophic levels, and attributes the non-additivity of effects of fish and stoneflies on mayfly growth to an interaction modification whereby trout odour reduced the impact of stone flies on Baetis behaviour.

Bedazzled by flowers - Nickolas M. Waser; L. Chittka (Nature, 1998)
It is concluded that bees prefer to visit magenta-coloured flowers with a sparkling surface, which has implications for the idea of ‘pollination syndromes’, whereby certain plants are thought to be adapted to attract particular pollinators.

Does insect abundance affect bat activity? - ERIC R. Allen (1998)

Field Estimation of food-web complexity in a sub-alpine meadow - E. Garcia (1998)

Status and Trends of the Endangered Colorado Squawfish in the Upper Colorado River - Doug B. Osmundson; Kenneth P. Burnham (Transactions of the American Fisheries Society, 1998)
Status of the Colorado River population of the endangered Colorado squawfish Ptychocheilus lucius (recently renamed the Colorado pikeminnow) was investigated by (1) estimating adult numbers, (2) evaluating frequency of reproduction and recruitment, (3) identifying trends via changes in size structure over time, and (4) examining historical accounts for clues to former abundance. Adults and subadults were systematically captured from 278 km of river during 1991–1994. Larvae and age-0 fish were systematically sampled in two reaches during 1986–1994. Estimated number of adults in the upper 98 km averaged 253 individuals; estimated annual adult survival rate was 0.86. In the lower 181 km, estimates of subadults and adults combined averaged 344 individuals. A sizable pulse of subadults 300–400 mm long found in the lower reach in 1991 were from three year-classes, 1985–1987. By 1992, these were distributed throughout the river. Although catch rates of larger adults did not increase significa

Phoretic mite distributions among the burying beetle, Nicrophorus investigator - J. Dinnel (1998)

Topographic effects on upper elevation distribution and abundance of Artemisia tridentata Nutt - I. Fischer (1998)

A trade-off between the frequency and duration of bumblebee visits to flowers - K. N. Jones; J. Reithel; R. E. Irwin (Oecologia, 1998)
The potential for a trade-offs between these two components of pollinator service exists when visit duration depends on reward quantity; whether the trade-off is realized will depend on variation in nectar production and on whether pollinators forage systematically.

Types of disturbances that favor success of Matricaria perforata: a roadside vs. a cemetery - K. Guimond (1998)

Pollen transfer by natural hybrids and parental species in an Ipomopsis hybrid zone - Diane R. Campbell; Nickolas M. Waser; P. G. Wolf (Evolution, 1998)

Do beaver, Castor canadensis, follow optimal foraging in Gothic, Colorado - K. Lautenschlager (1998)

"Floral" scent production by Puccinia rust fungi that mimic flowers - Robert A. Raguso; B. A. Roy (Molecular Ecology, 1998)

Sapsuckers at work - P. R. Ehrlich; G. C. Daily (Whole Earth, 1998)

A brief overview of the Quaternary History of the Taylor River Basin - Keith A. Brugger (1998)

A comparison of behavior in two marmot populations - F. MacCarty (1998)

Effects of food supplementation on a population of golden-mantled ground squirrels, Spermophilus lateralis - Wendell Paddock (1998)

The effects of spatial isolation on male and female functions in Ipomopsis aggregata - N. Thorne (1998)

Allelopathic effects of Serphidium tridentatum upon two species of annuals - A. Zawacki; J. Baxter (1998)

Global climate change and ecosystem carbon storage: an experimental investigation of ecologically-mediated feedbacks to climate in montane meadows - S. R. Saleska (1998)

Cryptic species in the Puccinia monoica complex - B. A. Roy; D. Vogler; T. Bruns; T. Szaro (Mycologia, 1998)

Mineralogy of Tuckers Tunnel: Tuckerville, Hinsdale County, Colorado - Patrick E. Haynes; Paul F. Hlava (Rocks & Minerals, 1998)

A life to remember - J. D. Hallahan (1998)

Why do yellow-bellied marmots call? - Daniel T. Blumstein; Kenneth B. Armitage (Animal Behavior, 1998)
This work addressed if and how yellow-bellied marmot, Marmota flaviventris, alarm-calling behaviour was influenced by the presence or absence of both descendent and nondescendent kin, by using total r as a measure of the opportunity for kin selection.

A manual of the common North American species of the aquatic leafmining genus Hydrellia (Diptera: Ephydridae) - D. L. Deonier (1998)

Pollen competition and the frequency of hybridization between two species of Ipomopsis (Polemoniaceae) - R. Alarcon (1998)

Changes in Aspen Communities Over 30 Year in Gunnison County, Colorado - J. Crawford; S. NcNulty; J. Sowell (American Midland Naturalist, 1998)

Herbivory patterns in response to climate change in a sub-alpine meadow - J. Call (1998)

Survey of plant species diversity growing in the moss Aulacomnium sp - N. Doerr (1998)

Pollinator choice of flower size and sexual morph in Geranium richardsonii - A. Drew (1997)

Harry Gunnison Brown's Advocacy - Christopher K. Ryan (The American Journal of Economics and Sociology, 1997)
Abstract. Harry Gunnison Brown's fifty plus years of active advocacy of land value taxation are reviewed in the light of two recent articles. One indicates a waning interest and even understanding of Brown's chosen cause while the other demonstrates quite the opposite: the persistence and relevance of land value taxation. Brown's strategies are examined, drawing on his correspondence as well as his publications. It is suggested that evaluation of Brown's success or failure is a moot question in the sense that there was no one with whom to compare him.

Growth and Survival of Colorado Squawfish in the Upper Colorado River - Doug B. Osmundson; R. J. Ryel; T. E. Mourning (Transactions of the American Fisheries Society, 1997)
Growth and adult survival rates were estimated for the endangered Colorado squawfish Ptychocheilus lucius inhabiting the upper Colorado River by using data from fish captured during 1990–1995. Mean annual growth rates of fish aged 3–6 years ranged from 32.2 (age 6) to 82.0 (age 3) mm/year. Growth rates for older fish were highest for fish 400–449 mm total length, TL, (42.7 mm/year) and declined to 19.8 mm/year for fish 500–549 mm TL. Fish 550 mm and longer grew an average 9.5 mm/year. Survival rates for fish 550 mm and longer were estimated by comparing measured size distributions with simulated stable age and size distributions; these ranged from 0.83–0.87, with the best fit at 0.85. Though lack of historical data precludes comparisons with past growth and survival rates, our data serve as a baseline for future population monitoring efforts.

Lesquerella vicina (Brassicaceae), a New Species from the Uncompahgre River Valley in Western Colorado - J. T. Anderson; James L. Reveal; Reed C. Rollins (Novon, 1997)
John L. Anderson, James L. Reveal, Reed C. Rollins, Lesquerella vicina (Brassicaceae), a New Species from the Uncompahgre River Valley in Western Colorado, Novon, Vol. 7, No. 1 (Spring, 1997), pp. 9-12

Does sociality drive the evolution of communicative complexity? A comparative test with ground-dwelling sciurid alarm calls - Daniel T. Blumstein; Kenneth B. Armitage (American Naturalist, 1997)
While sociality has been hypothesized to drive the evolution of communicative complexity, the relationship remains to be formally tested. We derive a continuous measure of social complexity from demographic data and use this variable to explain variation in alarm repertoire size in ground-dwelling sciurid rodents (marmots, Marmota spp.; prairie dogs, Cynomys spp.; and ground squirrels, Spermophilus spp.). About 40% of the variation in alarm call repertoire size was explained by social complexity in the raw data set. To determine the degree to which this relationship may have been influenced by historical relationships between species, we used five different phylogenetic hypotheses to calculate phylogenetically independent contrasts. Less variation was significantly explained in contrast-based analyses, but a general positive relationship remained. Social complexity explained more variation in alarm call repertoire size in marmots, while sociality explained no variation in repertoire si

Inter- and intraspecific variation in the acoustic habitats of three marmot species - Daniel T. Blumstein; J. C. Daniel (Ethology, 1997)
Closely related species often have remarkably different vocalizations. Some of the variation in acoustic structure may result from species adapting their calls to maximize transmission through their acoustic environ- ments. We document the relative magnitude of inter- and intraspecific variation in acoustic transmission properties of the habitats of three closely related marmot species to study the relative importance that the acoustic environment may have played in selecting for species-specific marmot alarm calls. We used spectrogram cor- relation to quantify the degree to which pure tones and alarm calls changed as they were broadcast through matmot home ranges to describe the acoustic habitats of golden (M1. candata aurea), yellow-bellied (M. flaviventris), and alpine (Af. marmota L.) marmots. Species lived in quantifiably different acoustic habitats. One analysis partitioned variation between species and between marmot social groups (nested within species). We found significant in

Alarm calling in yellow-bellied marmots: I. The meaning of situationally variable alarm calls - Daniel T. Blumstein; Kenneth B. Armitage (Animal Behaviour, 1997)
Yellow-bellied marmots, Marmota flaviventris were reported to produce qualitatively different alarm calls in response to different predators, but there was significant individual variation in call structure, but acoustic parameters that were individually variable were not used to communicate variation in risk.

On the implications of species-area relationships for endemism, spatial turnover, and food web patterns - J. Harte; A. Kinzig (Oikos, 1997)
Consequences of species-area relationships (SARs) of the form S = cA are derived. One consequence is an endemics-area relationship (EAR); it is of the same power-law form as the SAR but with an exponent z' that is a function only of z and that always exceeds unity. An explicit formula is derived for the dependence of species turnover in space on census plot size, interplot distance, and the SAR exponent z; this formula can be used to determine z over spatial scales that are too large to permit direct estimate of z by censusing of nested patches. The areal dependence of link-species patterns observed in food webs is also examined; SARs are shown to imply the approximate, but not exact, area-independence of link-species relationships of the form L = kSy, where L is the number of trophic links and y < 2. A relationship between the average range of species in a habitat patch and the exponent z is also derived, leading to the result that average range is a decreasing function of both patch

Terrestrial ecosytem feedbacks to global climate change - D. A. Lashof; B. J. DeAngelo; S. R. Saleska; J. Harte (Annual Review Energy Environment, 1997)
Anthropogenic greenhouse gases are expected to induce changes in global climate that can alter ecosystems in ways that, in turn, may further affect climate. Such climate-ecosystem interactions can generate either positive or negative feedbacks to the climate system, thereby either enhancing or diminishing the magnitude of global climate change. Important terrestrial feedback mechanisms include CO2 fertilization (negative feedbacks), carbon storage in vegetation and soils (positive and negative feedbacks), vegetation albedo (positive feedbacks), and peatland methane emissions (positive and negative feedbacks). While the processes in- volved are complex, not readily quantifiable, and demonstrate both positive and negative feedback potential, we conclude that the combined effect of the feedback mechanisms reviewed here will likely amplify climate change relative to current projections that have not yet adequately incorporated these mechanisms. CONTENTS

Cyclic Colonization in Predictably Ephemeral Habitats: A Template for Biological Control in Annual Crop Systems - S. A. Wissinger (Biological Control, 1997)
It is argued that ACSs are “predictably ephemeral” habitats that present a selective environment that is different from that commonly envisioned for disturbed or early successional habitats, and therefore, effective biological control strategies in ACSs must include a landscape ethic that provides an abundance of permanent habitats that can act as reservoirs for indigenous and introduced natural enemies.

ALTERED STREAMFLOW AND SEDIMENT ENTRAINMENT IN THE GUNNISON GORGE1 - John G. Elliott; Randolph S. Parker (JAWRA Journal of the American Water Resources Association, 1997)
ABSTRACT: The Gunnison River in the Gunnison Gorge is a canyon river where upstream dams regulate mainstem discharge but do not affect debris‐flow sediment supply from tributaries entering below the reservoirs. Regulation since 1966 has altered flood frequency, streambed mobility, and fluvial geomorphology creating potential resource‐management issues. The duration of moderate streamflows between 32.3 and 85.0 m3/s has increased threefold since 1966. This, along with flood‐peak attenuation, has facilitated fine‐sediment deposition and vegetation encroachment on stream banks. The Shields equation and on‐site channel geometry and bed‐material measurements were used to assess changes in sediment entrainment in four alluvial reaches. Sand and fine gravel are transported through riffle/pool reaches at most discharges, but the cobbles and boulders composing the streambed in many reaches now are infrequently entrained. Periodic debris flows add coarse sediment to rapids and can increase pool

The effect of mermithid parasitism on predation of nymphal Baetis bicaudatus (Ephemeroptera) by invertebrates - S. A. Vance; B. L. Peckarsky (Oecologia, 1997)
A number of hypotheses are presented to explain why the parasite causes increased predation on its host, including the large size of the parasite affecting the sensory abilities of the host, the larger energetic costs of escape behavior for parasitized individuals, and natural selection from fish predation against drifting behavior by Parasitized individuals.

Insect numbers and diversity along three roadsides of different ages - C. Gubser (1997)

Why red flowers are not invisible to bees - L. Chittka; Nickolas M. Waser (Israel Journal of Plant Sciences, 1997)
A pervasive idea among pollination biologists is that bees cannot see red flowers. This idea has led many workers to assume that red coloration is an adaptation by which flowers exclude bees as visitors. However, recent empirical and theoretical evidence strongly supports the alternative view, that red flowersarevisible to bees. Our purpose is to marshal this evidence from physiology, behavior, and ecology. First, we define the spectral boundary between orange and red, and show that the visual spectrum of all bee species studied to date extends enough into long wavelengths to provide sensitivity to red light. Such sensitivity differs from the ability to discriminate different monochromatic lights, and we argue that bees will be unable to discriminate such lights above about 550 nm. Second, we point out that flowers do not reflect monochromatic lights. Instead many of them, particularly those that appear red, orange, yellow, and white to humans, have reflectance patterns that are essent

Effects of pre-dispersal selection on offspring growth and survival in Erythronium grandiflorum - M. B. Cruzan; J. D. Thomson (Journal of Evolutionary Biology, 1997)
AbstractEffects of pre‐seed‐dispersal processes on offspring vigor were examined in Erythronium grandiflorum using manipulations of the number of pollen donors contributing to the pollen pool and comparisons of means and variances in offspring growth measurements. There were no effects of the number of donors on measures of pollen‐tube growth, ovule abortion, seed set, mean seed weight, or seedling germination. Seeds from pollinations with only one donor produced corms that averaged 5% lighter after one season of growth and had lower overall survival after three years compared to corms from pollinations with either three or ten donors. Patterns of within‐ and among‐family variance estimates for the different treatments were consistent with the hypothesis that less‐vigorous offspring were eliminated prior to seed dispersal in the multiple‐donor treatments. The difference in the growth of offspring from different treatments was apparently not due to pollen competition because pre‐zygotic

Analysis of pollinator foraging: tests for non-random behavior - K. N. Jones (Functional Ecology, 1997)
1. A standardized protocol for analysing the behaviour of pollinators foraging on more than one plant type (species or morph) is needed. 2. A protocol is presented in which the first step is to test whether foraging trips are homogeneous in the frequency of visits to each plant type, or whether there are two or more groups of pollinators with different foraging preferences. 3. Tests for foraging preference and constancy in the sequence of plants visited then should be made separately for each homogeneous group. 4. A hypothetical example is given in which ignoring heterogeneity of preference would lead to the acceptance of a false null hypothesis of random behaviour. 5. A real example is given in which heterogeneity of preference was the only non‐random aspect of pollinator behaviour (no significant positive constancy or overall preference), while transfer of powdered dye particles (pollen analogues) was assortative among floral morphs. 6. Heterogeneity of preference is probable, as man

Dynamics of reproductive allocation from juvenile and adult feeding: radiotracer studies - C. L. Boggs (Ecology, 1997)
Nutrients used in reproduction may come from adult feeding or reserves stored from the juvenile stage. The dynamics of allocation from these sources are predicted to differ among nutrient types, depending on the relative availability of each nutrient type from adult and juvenile feeding. Using radiotracer techniques, I examined reproductive allocation of glucose and amino acids from adult and juvenile sources in two nymphalid butterflies, Euphydryas editha and Speyeria mormonia. The species used were intermediate in expected importance of adult nutrients to egg production, with abundant carbohydrates but few nitrogenous compounds available from the adult diet. As predicted, for compounds abundantly available in the adult diet, incoming nutrients were used in preference to stored nutrients. For compounds present in low amounts in the adult diet, juvenile reserves were used throughout adult life, although adult sources were used if available. Nutrients received by the female from the mal

Reproductive allocation from reserves and income in butterfly species with differing adult diets - C. L. Boggs (Ecology, 1997)
Allocation of stored and incoming nutrients to reproduction determines an organism’s age-specific fecundity curve. In holometabolous insects, differences among species in the shape of the curve are correlated with differences in the potential importance of adult food to reproduction. I examined allocation patterns underlying this association. Specific changes throughout life in body mass and reproductive effort were predicted to result from use of stored vs. incoming nutrients for reproduction and other metabolic needs at each age. Data for three nymphalid butterfly species, Euphydryas editha, Speyeria mormonia, and Heliconius charitonius, were compared with the predictions. These three species differ in adult diet and fraction of oocytes mature at adult emergence (hence, potential for adult nutrients to be used to make eggs), with E. editha showing the least potential for use of adult nutrients in egg production and H. charitonius showing the greatest potential. For all three species,

Effects of pollinators, herbivores, and seed predators on flowering phenology - Alison K. Brody (Ecology, 1997)
The evolution of flowering phenology has most often been examined in light of one set of organisms, namely pollinators. However, the patterns of flowering phenology observed in nature are likely to reflect evolutionary compromises in response to a variety of selective forces. Two of the most important potentially opposing selective forces that could elicit such a compromise are pollinators and pre-dispersal seed predators. Using a case study from my own work on the pollinators and pre-dispersal seed predators of two members of the Polemoniaceae, Polemonium foliosissimum and Ipomopsis aggregata, I show that the outcome of selective pressures is not always predictable by examining one group of organisms or another. In addition, the outcome of separate and combined selective pressures is variable among years. Thus I show that only by considering all organisms that affect the fitness of a plant may we gain a complete understanding of the evolution of floral traits. I argue that we must acc

Analyzing pollinator-mediated selection in a plant hybrid zone: hummingbird visitation patterns on three spatial scales - Diane R. Campbell; Nickolas M. Waser; E. J. Melendez-Ackerman (American Naturalist, 1997)
Clines across hybrid zones can be produced by several forms of natural selection. We illustrate an approach to studying pollinator-mediated selection in plant hybrid zones, using two species of Ipomopsis (Polemoniaceae) as a model system. We measured visitation to flowers in natural and experimental populations by two major types of pollinators, hummingbirds and hawkmoths, at up to three different spatial scales. Using measures of pollinator visitation, we calculated phenotypic selection gradients and characterized the form of selection in the hybrid zone. Hummingbirds overvisited Ipomopsis aggregata compared with Ipomopsis tenuituba and morphological hybrids at all spatial scales, especially the largest scale of kilometers. These responses may depend in part on the presence of other hummingbird-visited plants in the community. Hummingbird behavior produced directional selection favoring wide corolla tubes and intense red coloration. Hawkmoths, in contrast, overvisited plants with narr

A look at leaf litter diversity in a grazed and non-grazed aspen grove - J. L. Hayes (1997)

Alarm calling in yellow-bellied marmots: II. The importance of direct fitness - Daniel T. Blumstein; J. Steinmetz; Kenneth B. Armitage; J. C. Daniel (Animal Behaviour, 1997)
Alarm calling in group-living yellow-bellied marmots is a form of direct parental care and inclusive fitness, broadly defined, is of little importance for the maintenance of alarm calling.

Community composition in mountain ecosystems: climatic determinants of montane butterfly distributions - C. L. Boggs; Dennis D. Murphy (Global Ecology and Biogeography Letters, 1997)
Carol L. Boggs, Dennis D. Murphy, Community Composition in Mountain Ecosystems: Climatic Determinants of Montane Butterfly Distributions, Global Ecology and Biogeography Letters, Vol. 6, No. 1, Mountain Ecology: Organism Responses to Environmental Change (Jan., 1997), pp. 39-48

Pollinators, Flowering Plants, and Conservation Biology - C. A. Kearns; David W. Inouye (BioScience, 1997)
M ore than a century ago, Darwin (lg59) observed that number of bumblebees in any district depends in a great measure upon the number of fieldmice, which destroy their combs and nests ... che number of mice is largely Jependent, as everyone knows, on the number of cats .. .it is quite credible that the presence of a feline animal in large numbers in a district might uetermine, through the intervention first of mice and then of bees, the frequency of certain flowers in that district! (p. -125). Dar '{in recoglllzed the importance of interactions among organisms, specifically the role that pollinators play as links in communities. Yet, almost 140 years later, our understanding of pollination interactions is still rudimentary. The extent of dependence and linkage in pollination sys-

Introduced plant species in Gothic, Colorado: invasive or harmless? - C. Gubser; A. McCarthy (1997)

Ants, competition, and diversity: part one - K. K. Ingram (1997)

Genetic correlation between biomass allocation to male and female functions in a natural population of Ipomopsis aggregata - Diane R. Campbell (Heredity, 1997)

Olfactory versus visual cues in a floral mimicry system - B. A. Roy; Robert A. Raguso (Oecologia, 1997)
It is found that pseudoflower fragrance can attract visitors by itself, and the ability of insects to differentiate pseudoflowers from true flowers by their fragrance may be important in the evolution of the mimicry system.

Nature's Services: Societal Dependence on Natural Ecosystems - A. Wilcox; J. Harte (1997)

The effects of large invertebrates on the development of cannibal morphology in the tiger salamander, Ambystoma tigrinum nebulosum - R. T. Cargille (1997)

Aliens mine peanuts: root-elongation tests and the effects of heavy metals on Carex at the Peanut Mine, Crested Butte, CO) - R. Roland; J. L. Hayes (1997)

Hummingbird behavior and mechanisms of selection on flower color in Ipomopsis - E. J. Melendez-Ackerman; Diane R. Campbell; Nickolas M. Waser (Ecology, 1997)

A long-term study on the effects of temporal variation in precipitation on the flowering behavior of Androsace septentrionalis L. (Primulaceae) - W. Lee (1997)

Natural variation in pollinator composition and services: effects on the reproductive success of Ipomopsis aggregata - M. M. Mayfield (1997)

The high life: a subalpine fir and Englemann spruce community in an avalanche zone - J. P. Oliva; S. Ochs (1997)

Effects of manure on germination of Bromus tectorum in contaminated mine soil - R. Roland (1997)

Richness and distribution of insects on a slope frequently disturbed by avalanches - Laura Warman (1997)

The evolution of specialization in lycaenid butterfly-ant mutualisms - A. M. Fraser (1997)

Changes in water relations for leaves exposed to a climate-warming manipulation in the Rocky Mountains of Colorado - M. E. Loik; J. Harte (Environmental and Experimental Biology, 1997)

Reproductive resource allocation in Delphinium nelsonii - A. Alvarado (1997)

Effects of interspecific pollen transfer between Ipomopsis aggregata and Castilleja linaerifolia (a case study of I. aggregata) - M. Alfaro (1997)

Case material choice by caddisfly larvae in the presence of a predator - J. Gifford; S. A. Lopez (1997)

Phenomenon of a moist environment shrub growing in dry conditions: why is it there? - Curtis Martin (1997)

Human roadside disturbance and natural avalanche disturbance: a richness and diversity comparison - D. Parson (1997)

Alien and endemic plant species richness and diversity in relation to disturbance at Rosy Point, Gothic, CO - C. Silapaswan (1997)

The effect of colors: what attracts snipe flies (Diptera: Rhagionidae, Symphoromyia Frauenfeld)? - H. Song (1997)

Concentration and color preference in nectar feeding birds - M. S. Adams (1997)

Biodiversity and ecosystem function: correlations among aboveground biomass, species richness, and soil organic matter - M. L. Holman (1997)

Response of mayfly larvae to fish odor: development of a bioassay to test chemical response - K. Maly (1997)

The effects of road proximity on pollinator visit to Mertensia ciliata - A. McCarthy (1997)

Competitive foraging interactions in a sub-alpine ant community - B. Peters (1997)

What attracts snipe flies (Diptera: Rhagionidae, Symphoromyia Frauenfeld)? The effects of CO2 and mammalian temperature - H. Song (1997)

Distribution of caddisfly larvae according to location and presence of predators in high mountain ponds - Laura Warman (1997)

Social interactions and natal dispersal of young golden-mantled ground squirrels (Spermophilus lateralis) - K. Jenderseck (1997)

Trapline foraging by bumble bees: II. Definition and detection from sequence data - J. D. Thomson; M. Slatkin; J. D. Thomson (Behavioral Ecology, 1997)
Trapline foraging—repeated sequential visits to a series of feeding locations—presents interesting problems seldom treated in foraging models. Work on traplining is hampered by the lack of statistical, operational approaches for detecting its existence and measuring its strength. We propose several statistical procedures, illustrating them with records of interplant flight sequences by bumble bees visiting penstemon flowers. An asymmetry test detects deviations from binomial expectation in the directionality of visits between pairs of plants. Several tests compare data from one bee to another frequencies of visits to plants and frequencies of departures to particular destinations are compared using contingency tables; similarities of repeated sequences within bees are compared to those between bees by means of sequence alignment and Mantel tests. We also compared observed movement patterns to those generated by null models designed to represent realistic foraging by non-traplining bees

Effects of experimental manipulation of inflorescence size on pollination and pre-dispersal seed predation in the hummingbird-pollinated plant Ipomopsis aggregata - Alison K. Brody; R. J. Mitchell (Oecologia, 1997)

Colony growth and reproduction in the ant species Formica neorufibarbis - Ian Billick (1997)

Plant and insect diversity and abundance: resilience in response to human disturbance - K. Smith; K. Smith (1997)

Effect of the presence of aphids (Aphididae) on oviposition in the pre-dispersal seed predator Hylemya (Delia) spp. on the host plant Polemonium foliossissimum (Polemoniaceae) - U. Lang (1997)

Differential predation of mayfly larvae and damselfly larvae by tiger salamanders - G. S. Keegan; Curtis Martin (1997)

Helianthella-ant mutualism - G. McCracken (1997)

Maintenance of polymorphism promoted by sex-specific fitness payoffs - H. H. Whiteman (Evolution, 1997)
crossing in an intimate plant herbivore relationship. I. Does outcrossing provide an escape from herbivores adapted to the parent plant? Evolution 48:454-464. TEMPLETON, A. R., AND B. READ. 1984. Factors eliminating inbreeding depression in a captive herd of Speke's gazelle. Zoo Biol. 3:177-199. VERNICK, K. D., H. FUJIOKA, D. C. SEELEY, B. TANDLER, M. AiKAWA, AND L. H. MILLER. 1995. Plasmodium gallinaceum: a refractory mechanism of ookinete killing in the mosquito, Anopheles gambiae. Exp. Parasitol. 80:583-595 VRIJENHOEK, R. C., AND P. I. LEBERG. 1991. Let's not throw the baby out with the bathwater: a comment on management for MHC diversity in captive populations. Conserv. Biol. 5:252254. WADE, M. J. 1977. An experimental study of group selection. Evolution 31:134-153. WAKELIN, D. 1985. Genetics, immunity and parasite survival. Pp. 39-54 in D. Rollinson and R. M. Anderson, ed. Ecology and genetics of host-parasite interactions. Academic Press, London. WATKINS, D. I., T L. GARBER, Z. W

Genetic and environmental variation in life-history traits of a monocarpic perennial: a decade-long field experiment - Diane R. Campbell (Evolution, 1997)
Directional and stabilizing selection tend to deplete additive genetic variance. On the other hand, genetic variance in traits related to fitness could be retained through polygenic mutation, spatially varying selection, genotype-environment interaction, or antagonistic pleiotropy. Most estimates of genetic variance in fitness-related traits have come from laboratory studies, with few estimates of heritability made under natural conditions, particularly for longer lived organisms. Here I estimated additive genetic variance in life-history characters of a monocarpic herb, Ipomopsis aggregata, that lives for up to a decade. Experimental crosses yielded 229 full-sibships nested within 32 paternal half-sibships. More than 5000 offspring were planted as seeds into natural field sites and were followed in most cases through their entire life cycle. Survival showed substantial additive genetic variance (genetic coefficient of variation ≈ 54%). Small differences at seedling emergence were magn

Time of day and visitation affects on nectar volumes throughout the day in Aquilegia caerulea - K. Jenderseck (1997)

Specialization and foraging ergonomics in a subalpine bumblebee Bombus appositus (Hymenoptera: Apidae) - M. C. Jost (1997)

Extrapolating from individual behavior to populations and communities in streams - B. L. Peckarsky; S. D. Cooper; A. R. McIntosh (Journal of the North American Benthological Society, 1997)
Biological processes, such as predator-prey or competitive interactions, occur at multiple spatial and temporal scales, but their impacts on the distribution, abundance, and fitness of organisms may only be detectable at some scales. This is because 1) small scale (local) processes may be constrained by large-scale (regional) processes, 2) the influence of organism movement changes with spatial scale, and 3) multiple small-scale processes may interact and produce variation that obscures large-scale patterns. Most ecologists would like to know the relevance of small-scale observations and experiments for large-scale patterns and processes acting over long time periods. In this paper we consider whether patterns of individual behavior translate in a straightforward way to patterns in population dynamics, community structure, or individual fitness at larger spatial and longer temporal scales. We illustrate our discussion with data from communities living in high altitude streams in wester

Patterns of color and nectar variation across an Ipomopsis (Polemoniaceae) hybrid zone - E. J. Melendez-Ackerman (American Journal of Botany, 1997)
Hybridization may uncouple adaptive trait combinations that are present in parental species. I studied variation in flower color and reward quality across a hybrid zone of Ipomopsis aggregata and I. tenuituba. Individuals from hybrid populations showed considerable variation in flower color using corolla reflectance measurements. Flower spectra of such individuals were either intermediate or else resembled those flowers from the parental species. Ipomopsis aggregata populations had consistently higher nectar production rates and higher nectar standing crops than either I. tenuituba or hybrids. Ipomopsis aggregata flowers also produced more dilute nectar than those of hybrids and I. tenuituba, but the actual concentration values were quite variable among populations of the same type. Overall, the nectar quality of hybrid flowers most resembled that of I. tenuituba flowers. Based on the observed interpopulation patterns of color‐reward associations in this hybrid zone, pollinators should

The effect of macroinvertebrate prey on the cannibalistic polymorphism in the tiger salamander Ambystoma tigrinum nebulosum - A. VanDeusen (1996)

Resource partitioning and per-flower foraging efficiency in two bumblebee species - L. Graham; K. N. Jones (American Midland Naturalist, 1996)

Untangling multiple factors in spatial distributions: Lilies, gophers, and rocks - B. Thomson; G. D. Weiblen; B. Thomson; S. Alfaro; P. Legendre (Ecology, 1996)
Despite broad consensus on the power of experiments, correlational studies are still important in ecology, and may become more so as spatial studies proliferate. Conventional correlation analysis, however, (1) fundamentally conflicts with the basic ecological concept of limiting factors, and (2) ignores spatial structure in data, which can produce spuriously high correlations. Especially for field data, bivariate scattergrams often show factor—ceiling" distributions wherein data points are widely scattered beneath an upper limit, due to the action of other factors. Although most ecological information in such a graph resides in the upper limit, standard correlation/regression does not characterize such limits. If other factors have been measured, path analysis may be useful, but otherwise, direct description of ecological ceilings is desirable. Objective methods for doing so are barely known to ecologists; we review recent proposals for statistical testing and data display. For correct

Differential behavioural responses of mayflies from stream with and without fish to trout odour - B. L. Peckarsky; A. R. McIntosh (Freshwater Biology, 1996)
1. In streams, mayflies (Order Ephemeroptera) are at risk from fish feeding visually in the water column. The effect of fish odour on the behaviour of Baetis bicaudatus from a fishless stream and a trout stream was investigated in four large oval tanks supplied with water from the fishless stream.2. For each mayfly population, mayfly positioning on the substratum and movement in the water column (drift) were measured during the day and night, over 3 days. Brook trout (Salvelinus fontinalis) odour was added to two tanks to test the effect of a threat from fish.3. Throughout the experiment more mayflies from the trout stream were observed on the substratum surface and in the water column during the night than the day, but the magnitude of night drift was less in tanks with fish odour.4. Baetis from the fishless stream also displayed a nocturnal periodicity in drift and positioning, but their night‐time drift was not affected by the presence of fish odour. On the first day of the experime

Trapline foraging by bumblebees: I. Persistence of flight-path geometry - J. D. Thomson (Behavioral Ecology, 1996)
By setting out arrays of potted plants of Penstemon strictus, I tested whether freely foraging bumblebee (Bombus spp.) workers would establish regular foraging routes that reflected the geometry of the array. They did, passing through an asymmetrical array in a pattern that minimized interplant flight distances. After the array was changed to a symmetrical pattern, however, the experienced bees continued to show their previous asymmetrical flight patterns. New bees without experience on the asymmetrical array showed no asymmetry on the symmetrical array. I term this persistence of flight-path geometry "trapline holdover," and discuss its implications for the study of animals' learning and foraging behavior.

Generalization in pollination systems, and why it matters - Nickolas M. Waser; L. Chittka; Mary V. Price; N. M. Williams; J. Ollerton (Ecology, 1996)
One view of pollination systems is that they tend toward specialization. This view is implicit in many discussions of angiosperm evolution and plant—pollinator coevolution and in the long—standing concept of pollination syndromes. But actual pollination systems often are more generalized and dynamic than these traditions might suggest. To illustrate the range of specialization and generalization in pollinators' use of plants and vice versa, we draw on studies of two floras in the United States, and of members of several plant families and solitary bee genera. We also summarize a recent study of one local flora which suggests that, although the colors of flowers are aggregated in phenotype space, there is no strong association with pollinator types as pollination syndromes would predict. That moderate to substantial generalization often occurs is not surprising on theoretical grounds. Plant generalization is predicted by a simple model as long as temporal and spatial variance in pollina

The short-term effects of cattle grazing on caddisfly populations - L. Beasley (1996)

Costs and benefits of sociality in yellow-bellied marmots (Marmota flaviventris): do noncolonial females have lower fitness? - C. Lenihan; D. H. Van Vuren; C. Lenihan (Ethology, Ecology and Evolution, 1996)
Whether an animal lives alone or in a group may have fitness consequences. Among yellow-bellied marmots (Marmota flaviventris), fitness is thought to be lower for noncolonial than for colonial females because juvenile survival, as indicated by trapping, is lower. Trapping, however, may not be an accurate estimate of survival. Low recapture rates of noncolonial juveniles may result from early dispersal due to maternal behavior, or higher mortality due to predation or inadequate resources for overwinter survival. Our objective was to determine if survival was lower for noncolonial than for colonial juveniles, and to determine the cause of the low recapture rate of noncolonial juveniles. Our results show that survival of noncolonial juveniles was not lower than that of colonial juveniles. Noncolonial juveniles were not more vulnerable to predation during the active season, nor was overwinter mortality higher. Some noncolonial juveniles did disperse early, and most moved away from the nata

Feedbacks, thresholds and synergies in global change: population as a dynamic factor - J. Harte (Biodiversity and Conservation, 1996)

Population time budget for the yellow-bellied marmot - Kenneth B. Armitage; C. M. Salsbury; E. L. Barthelmess; R. C. Grey; A. Kovach (Ethology, Ecology and Evolution, 1996)
Time budgets for 17 behaviors were analyzed for cohort, day-period, season- period and interactions among the main effects for three colonies of yellowbellied marmots in the Upper East River Valley in western Colorado. These effects explained up to 79% of the variation in the behaviors. Marmots allocated more time (40-60%, 110-265 min daily) above-ground to sitting/lying than to any other activity. Foraging was the other major activity (12-23%, 37 to 94 min daily). Vigilance/alert varied from 1.1 to 14.5% and from 12.0 to 71.7 min daily. Social status affected the time budget, especially time allocated to vigilance/alert. All other behaviors averaged about 5% or less except for out-of-sight and enterburrow. The adult male cohort spent significantly more time above-ground than all other cohorts and reproductive females allocated significantly more time to foraging than the other cohorts. The amount of time spent above-ground decreased linearly from the down-river site to the up-river si

Influence of cattle grazing on timing of post-breeding migration of Ambystoma tigrinum nebulosum - Charles Kelly (1996)

A comparison of avian species diversity in the Gothic area and Crested Butte - A. McMellan (1996)

The effects of various concentrations of fish chemicals on mayfly behavior - M. Robertson (1996)

Parental care and mate guarding in the apparently monogamous mountain bluebird, Sialia currucoides - Charles Kelly (1996)

Ectoparasites, fitness, and social behaviour of yellow-bellied marmots - D. H. Van Vuren (Ethology, 1996)
AbstractParasites can cause a loss of fitness for their hosts, potentially influencing social behaviour patterns of the host that promote or hinder parasite transmission. I studied yellow‐bellied marmots (Marmota flaviventris) and their ectoparasites to determine if ectoparasites reduce the fitness of marmots and to test whether ectoparasite loads differ according to social behaviour. Three taxa of ectoparasites were identified, fleas (Oropsylla Stanfordi), lice (Linognathoides marmotae), and mites (family Dermanyssidae). High ectoparasite loads were related to slower growth, lower overwinter survival, and reduced reproduction, suggesting that ectoparasites are a fitness cost for marmots. Ectoparasite loads were not higher in colonial than in noncolonial marmots, nor in polygynous than in monogamous adult males. There was a trend, however, toward higher ectoparasite loads in marmots that were dispersing rather than philopatric. Further, ectoparasite loads differed among groups of marmo

Methane consumption by montane soils: implications for positive and negative feedback with climate change - M. S. Torn; J. Harte (Biogeochemistry, 1996)

Upper mantle shear structure beneath the Colorado Rocky Mountains - Duk‐Kee Lee; Stephen P. Grand (Journal of Geophysical Research: Solid Earth, 1996)
A tomographic inversion of teleseismic shear wave delays has been performed using data collected in the 1992 Program for Array Seismic Studies of the Continental Lithosphere Rocky Mountain Front experiment. The shear wave residuals used as data were corrected for known crustal, sediment and topographic differences and thus were sensitive to mantle shear velocity variations beneath the Colorado array. Large differences in shear wave travel time are observed across Colorado and into western Kansas with a maximum difference of near 5 sec between the central Rockies in Colorado and a station in western Kansas. The shear wave residuals were inverted for shear wave velocity variations in the upper 350 km of the mantle beneath Colorado and Kansas. Large differences in mantle shear velocity are found between the Rockies and the Kansas Great Plains. The average shear velocity in the upper 200 km is about 9% greater beneath Kansas than beneath the Rockies. At greater depths, lateral variations a