Waiting on a mule deer crossing…
The label of this research neighborhood points toward cutthroat trout and high-elevation reservoirs, but the publications gathered here actually span a wider set of questions about how organisms — fish, amphibians, birds, plants, and the pathogens that infect them — persist and change in the mountains around the Gunnison Basin. The unifying thread is environmental sensitivity: how mountain species respond to shifts in climate, hydrology, land use, and the geography of their habitats. In a place like Gothic, Colorado, where snowpack, summer moisture, and short growing seasons set the tempo of life, even modest environmental changes can ripple through populations of trout in cold streams, tiger salamanders in subalpine ponds, bluebirds in meadow edges, and the wild flax plants that dot the hillsides.
Several concepts recur throughout the findings below. Epidemic dynamics refers to how a disease moves through a population over time — when outbreaks begin, how high they peak, and whether they fade out or persist. For a wild plant like Lewis flax (Linum lewisii) infected by the flax rust fungus (Melampsora lini), epidemic dynamics are measured by walking transects week after week and recording how many plants show rust pustules. Closely related is virulence evolution, the idea that pathogens can change over generations in how much harm they cause their hosts, sometimes in response to human interventions such as vaccine efficacy — how well a vaccine reduces infection or transmission. Although vaccines are not deployed in wild flax, the same evolutionary logic applies when environmental pressures shift which pathogen strains succeed.
Two more practical concepts shape how researchers extract patterns from messy field data. Generalized additive mixed models are a statistical tool that lets scientists fit curved, nonlinear relationships — for example, between humidity and disease prevalence — while accounting for the fact that repeated measurements at the same site are not independent. Historic records, including fossil populations and older field notes, provide a longer time horizon against which to compare modern observations, anchoring questions about change in a baseline that predates current monitoring.
Early contributions in this neighborhood were natural history studies that established baseline biology for mountain organisms. Addicott's (Addicott, 1977) examination of flower behavior in Lewis flax described the ecological and physiological controls on petal opening and abscission, work that later proved essential for interpreting how flax populations interact with their fungal pathogen. Rogers used historic records in the form of high-altitude fossil populations of the tiger salamander (Ambystoma tigrinum) to document facultative metamorphosis — the capacity of salamanders to either transform into terrestrial adults or remain aquatic — across deep time in Colorado, establishing that flexibility in life history has long characterized mountain amphibians.
The temporal progression and patterns of disease spread through host populations
Statistical modeling approach that allows for nonlinear relationships using smooth functions while accounting for random effects structure
We sequenced a 648 or 889 base pair region of the ND2 gene for at least 10 individuals from 53 contemporary populations. This table shows ND2 haplotyp...
Many species are threatened with extinction and efforts are underway worldwide to restore imperiled species to their native ranges. Restoration requir...
The scale of influence of hydrological and thermal conditions on disease remains uncertain for most wild plant pathosystems, thus restricting our abil...
In this study, we performed several transect surveys over the course of the 2021 summer field season to assess potential ecogeographical range determi...
1. Tropical tree species adapted to high wind environments might be expected to differ systematically in terms of stem allometry and life-history patt...
Assessing the potential for forest carbon (C) capture and storage requires accurate assessments of C in live tree tissues. In the vast majority of loc...
In the 1990s, field studies extended these baselines to behavior and land use. Kelly (Kelly, 1996) examined how cattle grazing influences the timing of post-breeding migration in the tiger salamander subspecies Ambystoma tigrinum nebulosum, an early signal that working landscapes shape amphibian phenology. A companion study (Kelly, 1996) documented parental care and mate guarding in mountain bluebirds (Sialia currucoides), filling in behavioral ecology for a familiar montane bird. Together, these older works set the stage by describing how mountain species behave under ordinary conditions — a necessary reference point for detecting change.
The most thoroughly developed line of recent research has used the Lewis flax and flax rust system as a model for understanding how environment shapes disease in wild populations. Duggal et al. (Duggal et al., 2023) mapped the geographic ranges of host and pathogen and found a striking asymmetry: flax itself is restricted to a narrow elevation band of roughly 2900 to 3100 meters and responds to slope, aspect, and land cover, while flax rust is evenly distributed across the full range of geographic settings the host occupies. Local flax density, rather than the broader spatial arrangement of flax patches across the landscape, was the key driver of whether rust was present. A practical implication is that as climate warms, the optimal range of flax may contract more than that of its pathogen, potentially intensifying disease pressure on shrinking host populations.
A multi-year monitoring study by Duggal et al. (Duggal et al., 2025) sharpened this picture by following four wild flax populations across five growing seasons. Hydrological conditions emerged as the dominant control on epidemic dynamics: higher average relative humidity and longer-lasting snow cover were associated with larger epidemic peaks, while temperature on its own showed no significant effect on maximum disease prevalence. The severe drought of 2023 was especially revealing — instead of the usual seasonal build-up of rust, the epidemic collapsed, producing disease depletion rather than normal progression. This demonstrated that extreme weather years can reorganize epidemic patterns in ways that average conditions do not predict.
Complementing the field observations, Miller et al. (Miller et al., 2022) built models linking within-plant infection processes to between-plant transmission and projected them forward under climate scenarios. They found that warming will initially slow transmission at both scales, because hotter conditions hinder plant growth and reduce spore dispersal and infection success. However, under high-emissions trajectories, moderate resurgences in disease spread are predicted as warming continues, suggesting that the short-term respite from disease could give way to renewed outbreaks. Miller (Miller, 2022) synthesized these flax results alongside studies of pathogen evolution and human disease, framing the flax rust system as a tractable window into how climate change reshapes infectious disease more broadly.
The temporal trajectory of this neighborhood is clear: foundational natural history work in the 1970s and 1980s gave way to behavioral and land-use studies in the 1990s, and since 2022 the focus has shifted sharply toward climate-driven disease ecology, with four of the eight publications appearing in that recent window. The current frontier combines multi-year field monitoring across multiple sites with mechanistic models that bridge scales, from individual plants to whole populations (Miller et al., 2022); (Duggal et al., 2025). Statistical advances — particularly the use of flexible nonlinear models to relate weather variables to disease prevalence — are allowing researchers to detect threshold effects and surprises like the 2023 drought collapse that simpler approaches would miss.
Emerging questions concern how generalizable the flax rust story is to other host-pathogen pairs in the Gunnison Basin, and whether the asymmetry between host and pathogen ranges (Duggal et al., 2023) is a common feature of mountain disease systems. There is also growing interest in connecting epidemiological findings to evolutionary outcomes, asking whether shifting climates will select for pathogens with different transmission strategies (Miller, 2022).
Several important uncertainties remain. It is not yet clear how repeated extreme years — droughts, heat waves, low-snow winters — will compound over decades, or whether disease systems can recover their typical dynamics between such events. The mechanistic basis for the strong role of humidity and snow cover in flax rust epidemics needs further work, including whether these cues act primarily on spore survival, host susceptibility, or both. More broadly, the cutthroat trout, salamanders, and bluebirds that lend this neighborhood its name have not been studied with the same recent intensity as the flax system, leaving open whether parallel climate-driven shifts are underway in aquatic and avian communities of the basin. The most promising direction for the next decade is to extend long-term, multi-site monitoring beyond plants and pathogens to vertebrates, and to integrate historic records with modern observations to detect change against a deeper baseline.
Addicott, F. T. (1977). Flower behavior in Linum lewisii: some ecological and physiological factors in opening and abscission of petals. American Midland Naturalist. →
Duggal, K., Jiranek, J., Machado, M., Smith, P., Miller, I., Metcalf, J. (2025). A multi-year case study highlighting the influence of hydrological conditions on epidemic dynamics in a natural plant pathosystem. Oikos. →
Duggal, K., Miller, I., Jiranek, J., Metcalf, J. (2023). A pathogen's spatial range is not constrained by geographical features in the flax rust pathosystem. Ecology and Evolution. →
Kelly, J. (1996). Influence of cattle grazing on timing of post-breeding migration of Ambystoma tigrinum nebulosum. →
Kelly, J. (1996). Parental care and mate guarding in the apparently monogamous mountain bluebird, Sialia currucoides. →
Miller, I. (2022). The ecology and evolution of pathogens in a changing world. →
Miller, I. F., Jiranek, J., Brownell, M., Coffey, S., Gray, B., Stahl, M., Metcalf, C. J. E. (2022). Predicting the effects of climate change on the cross-scale epidemiological dynamics of a fungal plant pathogen. Scientific Reports. →
Rogers, K. L. (1985). Facultative metamorphosis in a series of high altitude fossil populations of Ambystoma tigrinum (Irvingtonian: Alamosa County, Colorado). Copeia. →