National Forest Plan Amendments and Habitat Management

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Research Primer

Background

Mountain ecosystems like those surrounding the Rocky Mountain Biological Laboratory in Gothic, Colorado, sit at the leading edge of climate change. Snowpack is shrinking, growing seasons are lengthening, and species are shifting their ranges upslope. But the relationship between climate and ecosystems is not a one-way street. The plants, soils, and microbes of alpine and subalpine landscapes also feed back to the climate system — releasing or storing carbon, changing how much sunlight the land surface reflects, and altering fluxes of greenhouse gases like methane. Understanding these feedbacks across spatial scales, from a single soil core to an entire elevation gradient, is essential for predicting what the Gunnison Basin will look like in 50 or 100 years.

A few key concepts anchor this area of research. Climate change feedbacks can be positive (amplifying warming, as when thawing soils release more carbon to the atmosphere) or negative (dampening warming, as when extra carbon dioxide fertilizes plant growth that pulls carbon back into vegetation). Ecosystem function refers to the processes — carbon and nutrient cycling, productivity, decomposition — that determine how much carbon a landscape stores and how much it loses. Researchers track these processes using measurements like aboveground primary productivity (the new plant biomass produced each year) and net ecosystem exchange (the balance of carbon coming in through photosynthesis versus going out through respiration). Functional traits, such as specific leaf area (the ratio of leaf area to dry mass), provide a shorthand for how plants use resources and how communities will respond to change.

Because mountain landscapes vary dramatically over short distances, elevation gradients serve as natural laboratories: moving up a mountain can mimic moving back in time to colder conditions, or forward in time as warmer conditions creep upslope. This space-for-time approach, combined with manipulative climate change experiments that warm plots or alter precipitation, lets researchers test how community structure, body size, and trait variation will reorganize as the climate shifts. Scaling these plot-level findings up to whole landscapes is one of the central challenges of the field.

Foundational work

The foundation of climate feedback research at RMBL was laid in the 1990s by John Harte and colleagues. A landmark study of montane soils around Gothic showed that well-drained mountain soils consume atmospheric methane, but that warmer and drier conditions could either enhance or suppress this sink — meaning the same soils could shift between being a negative feedback (cooling) and a positive feedback (warming) depending on how climate change unfolds (Torn & Harte, 1996). A complementary synthesis placed these field findings in a global context, arguing that terrestrial ecosystem feedbacks — including CO2 fertilization, soil and vegetation carbon storage, albedo changes, and methane emissions — would on balance amplify climate change beyond what climate models of the time projected (Lashof et al., 1997).

At roughly the same time, Harte addressed the problem of scale directly, asking how results from small experimental plots could be extended to entire landscapes and used to inform global climate models (Harte, 1998). That question — how to move from a meadow at Gothic to a meaningful prediction for the Gunnison Basin or the Rocky Mountains as a whole — has framed the research area ever since.

Key findings

The most robust finding from this body of work is that mountain ecosystems are active participants in the climate system, not passive responders. Montane soils consume methane at rates sensitive to soil moisture and temperature, so changes in snowpack and summer drying can flip the sign of this feedback (Torn & Harte, 1996). When integrated with other terrestrial processes, the combined feedback effect is expected to amplify warming, with peatland methane release and changes in vegetation albedo joining soil carbon dynamics as the dominant levers (Lashof et al., 1997).

A second thread concerns how variation within plant communities translates into ecosystem function. Work in subalpine meadows tested whether reducing the variance of specific leaf area within a plot would change net carbon exchange or biomass production. Reductions in trait variance did not produce a detectable difference in net ecosystem exchange, but biomass did differ modestly between manipulated and control plots, hinting that trait variation matters for productivity even when whole-system carbon flux appears buffered (Kvam, 2013). These results are preliminary but point toward a broader principle: the diversity of traits within a community, not just the average, can shape how ecosystems respond to change.

A third thread addresses the organisms themselves. Mountain passes act as physiological barriers because narrow seasonal temperature ranges in the tropics, and steep gradients in temperate mountains, constrain how easily species can move across elevations as climates shift (Sheldon et al., 2018). At the microbial scale, large-scale patterns in abundance and diversity appear to follow some — but not all — of the macroecological rules developed for plants and animals, suggesting that the microorganisms driving soil carbon and nitrogen cycling have their own biogeography that must be incorporated into feedback predictions (Dickey et al., 2021).

Current frontier

Early work in the 1990s established the basic feedback architecture — which processes amplify or dampen warming, and roughly how strong they are. Research since 2015 has shifted toward finer-grained questions about the organisms and traits that mediate those feedbacks. The synthesis of mountain pass physiology brought renewed attention to how thermal constraints shape range shifts in a warming climate (Sheldon et al., 2018). More recent work has asked whether microbial communities, which control much of the soil carbon cycle, follow predictable macroecological patterns that could be built into models (Dickey et al., 2021). The newest contributions push into intraspecific variation: a 2025 review of bumble bees synthesizes how body size variation, driven by temperature and other environmental factors, scales up to influence pollination services and population persistence under global change (Fitzgerald, 2025).

The trajectory is clear — from quantifying bulk fluxes, to mapping spatial patterns, to understanding the trait-level and individual-level variation that determines how ecosystems will reorganize. New methods, including airborne LiDAR, GIS-based solar radiation modeling, and herbarium-based reconstructions of historical communities, are extending these questions across larger landscapes and longer time horizons than were possible a generation ago.

Open questions

Several major uncertainties remain. How do plot-scale measurements of carbon flux, methane consumption, and trait variation actually scale to entire watersheds like the East River, where topography, aspect, and snowpack vary dramatically over short distances? Will the methane sink in well-drained Gothic soils strengthen or weaken as snowpack continues to decline? How much do microbial communities — and their biogeography — need to be resolved before climate models can accurately predict soil carbon feedbacks? And as bumble bees, butterflies, and other key pollinators shift in body size and elevation, what cascading effects will those changes have on the plant communities that anchor alpine carbon storage? Answering these questions will likely require tighter integration of long-term monitoring at RMBL with remote sensing, trait databases, and manipulative experiments — turning the Gunnison Basin into a model system for predicting climate feedbacks across mountain landscapes worldwide.

References

Dickey, J. et al. (2021). Do microorganisms obey macroecological rules? Authorea. →

Fitzgerald, J. (2025). Dimensions of difference: Multi-scale consequences of trait variation in bumble bees. →

Harte, J. (1998). Ecological Feedbacks to Global Warming: Extending Results from Plot to Landscape Scale. Aspen Global Change Institute. →

Kvam, I. (2013). The effect of plant trait variation on plant production. RMBL Independent Research. →

Lashof, D. et al. (1997). Terrestrial ecosystem feedbacks to global climate change. Annual Review of Energy and the Environment. →

Sheldon, K. S., Huey, R. B., Kaspari, M. & Sanders, N. J. (2018). 50 years of mountain passes: A perspective on Dan Janzen's classic article. American Naturalist. →

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

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