Asking the pikas politely…
Investigates how mustard plants and related alpine species evolve and plastically respond to shifting snowmelt timing, precipitation, and aridity across elevational gradients in the Rocky Mountains.
The mountains around Gothic, Colorado are warming rapidly, snow is melting earlier, and summers are becoming drier. For plants rooted in place, these changes raise a fundamental question: can populations evolve fast enough to keep up, or will they decline, shift uphill, or disappear? Research at the Rocky Mountain Biological Laboratory (RMBL) has used the native mustard Boechera stricta and its relatives as a window into how alpine and subalpine plants respond to climate and seasonal change through both rapid evolutionary change and flexible individual responses.
A few key concepts run through this body of work. Local adaptation occurs when populations evolve traits that give them higher fitness in their home environment than transplants from elsewhere — a pattern tested directly through reciprocal transplant experiments, in which plants from different elevations are grown together in common gardens up and down the mountain. Phenotypic plasticity is a different strategy: a single genotype produces different traits (such as flowering time or leaf thickness) depending on conditions, without any genetic change. Distinguishing plasticity from genetic adaptation matters because only heritable change accumulates across generations. Researchers also study clines (gradual trait changes across an environmental gradient, such as elevation) and the strength of phenotypic selection, which measures how strongly traits influence reproductive success.
Several more specialized ideas appear in the findings below. Balancing selection maintains multiple genetic variants in a population — for example, when different versions of a defense chemistry gene each do better in different conditions. Conditional neutrality describes alleles that help in one environment but cause no harm in another. Gene flow, the movement of genes between populations through pollen and seed dispersal, can rescue declining populations if it brings in well-suited variants — but only if it happens fast enough. Finally, herbivory (consumption by insects and other animals) and aridity (water limitation) act alongside temperature as agents of selection, sometimes pushing traits in opposing directions. These concepts together help explain why predicting plant futures under climate change is hard: it depends on generation time, genetic variation, dispersal, and the interaction of multiple stressors.
The research program at RMBL on alpine plant evolution was anchored by long-term observations of flowering phenology paired with field-based quantitative genetics. A landmark study combined a 38-year flowering record with common garden experiments to show that Boechera stricta has advanced its flowering by roughly a third of a day per year since the 1970s, driven by earlier snowmelt and warmer temperatures, and that this shift reflects both plasticity and genetic adaptation . A companion synthesis emphasized that populations facing climate change will rarely persist through a single mechanism, but rather through some combination of migration, plasticity, and adaptation depending on generation time, mating system, and genetic architecture . Together with a broader review of plant adaptation genetics , these papers established flowering time as a model trait for studying rapid evolution in the wild.
Environmental condition characterized by limited water availability
When a genotype produces different phenotypes under differing environmental conditions
The process by which traits influence fitness, measured through directional and quadratic selection differentials relating trait values to reproductiv...
Consumption of plant material by animals, measured as browse occurrence on host plants
Movement of genes between populations through migration and reproduction
An evolutionary process in which a population evolves to become more suited to its local environment through natural selection, resulting in higher fi...
The ability of organisms to adjust to changing climatic conditions through genetic, phenotypic, or behavioral changes
Twice weekly censuses recording plant vital status, reproductive phenology, and fitness components including flower and fruit production. Weekly asses...
A large-scale reciprocal transplant experiment across five elevational gardens with factorial snow and temperature manipulations to test local adaptat...
A factorial field experiment manipulating snowmelt timing using black shade cloth and summer precipitation using rainout shelters in a split-plot desi...
Greenhouse factorial experiment manipulating water availability (3 levels) and nutrient supply (2 levels) to test resource limitation effects on fitne...
Weekly monitoring of plant phenology, morphological traits, and density across an elevational gradient to assess phenotypic plasticity in response to ...
Genomic sequencing and demographic modeling using GADMA2 to estimate historical gene flow patterns and migration rates between populations across elev...
Balancing selection is frequently invoked as a mechanism to maintain variation within and across populations. However, rigorous tests demonstrating ba...
Identification of the causal genes that control complex trait variation remains challenging, limiting our appreciation of the evolutionary processes t...
Climate change has induced pronounced shifts in the reproductive phenology of plants, yet we know little about which environmental factors contribute ...
This file contains the data to analyze the environmental correlates of flower color variation. The results are laid out in the text (Environmental cor...
This file contains the data for the choice experiment.
This file contains the data for the no choice experiment
This file contains data from transects in natural populations on individual plants. This dataset supports the section on the methods and results calle...
Early QTL work mapped the genetic basis of these traits to specific chromosomal regions. A large-effect locus influencing flowering time was identified and shown to carry a measurable fitness advantage in the field (Anderson et al., 2011), and subsequent genome-wide analyses revealed that local adaptation in B. stricta arises from many loci, with about 8% of the genome showing conditional neutrality and a smaller fraction showing genetic trade-offs between environments (pub from 2013).
Across dozens of studies, a coherent picture has emerged: B. stricta populations are locally adapted across elevation, and climate change is disrupting that match. Reciprocal transplants spanning more than 106,000 individuals showed that experimental snow removal — simulating future conditions — cut the probability of reproduction in low-elevation families by 75%, with population growth rates falling below replacement at the lowest gardens (Anderson & Wadgymar, 2020). Snow addition, by contrast, restored local adaptation and shifted the optimum toward lower-elevation genotypes (study from 2017). Snow removal alone advanced flowering by about a week, comparable to two or three decades of warming (study from 2015), and these effects extend across generations: parental snow environments influenced offspring germination and seed mass, with transgenerational plasticity sometimes exceeding within-generation responses (Wadgymar et al., 2018).
Selection on traits is neither simple nor constant. Stabilizing selection on leaf traits emerges only when data are integrated across multiple years, while single-year analyses suggest weaker directional patterns, and viability selection before flowering can oppose fecundity selection afterward (Wadgymar et al., 2017). Herbivory and water availability act as divergent agents of selection on leaf traits, with stabilizing selection on specific leaf area but directional selection favoring greater succulence (Jameel et al., 2025). Defense chemistry is shaped by balancing selection: alternative alleles at glucosinolate-biosynthesis genes have opposite fitness effects under drought versus herbivory, and the resulting chemical polymorphism varies from 0 to 100% across hundreds of natural populations (Carley et al., 2021). Flower color shows a parallel story, with purple-flowered plants more common at higher elevations and on south-facing slopes, lower foliar herbivory on pigmented individuals (study from 2018), and clear environmental and genetic components to the polymorphism (study from 2017).
Genetic architecture also matters for the pace of evolution. A young chromosomal inversion that arose since the last glaciation carries multiple linked loci controlling flowering time and defense, and is under positive selection in a hybrid zone (Lee et al., 2017). But genetic variation for key traits like flowering phenology contracts when plants are grown in warmer, drier conditions, suggesting the raw material for adaptation may shrink precisely where it is needed most (Bemmels & Anderson, 2019). Resource stress further reshapes trade-offs: negative genetic covariances between growth and reproduction appear only under severe drought combined with low nutrients (MacTavish & Anderson, 2020).
Early work in the 2010s established that B. stricta is locally adapted and evolving in response to climate. Recent studies since 2020 have shifted toward integrating evolution with demography to forecast persistence. The most ambitious effort modeled eco-evolutionary dynamics across 102,272 transplants from 115 source populations over up to nine years and concluded that neither local adaptation nor natural gene flow will be sufficient to rescue B. stricta from projected climate change, with the lowest-elevation sites already demographically unsustainable (Anderson et al., 2025). A commentary in Science underscored the severity: gene flow in this largely self-pollinating species is too slow, and unassisted upslope migration cannot keep pace (Aitken, 2025). New experimental work has begun manipulating multiple climate drivers simultaneously, showing that elevated CO2 enhances photosynthesis across genotypes but does not offset the fitness costs of warming (Denney et al., 2024), and that combined CO2 and temperature changes impose novel selection on allocation and leaf traits (Denney & Anderson, 2025).
Methodologically, the field is moving toward longer time horizons, demographic models that project lineage growth rates rather than annual fitness, and explicit tests of how stressors interact. Drought-by-herbivory experiments now show that defense polymorphism may persist across a wide range of conditions but is eroded by increasing aridity, suggesting that climate change could homogenize genetic variation that has been stable for millennia (Carley et al., 2025). Researchers are also paying renewed attention to microrefugia — small patches of cooler or wetter microhabitat that might buffer local populations in the short term (Denney et al., 2020).
The central unresolved question is whether assisted migration, microrefugia, or yet-undiscovered sources of plasticity can buy time for populations that natural processes alone cannot save. How will defense polymorphisms, flower color variation, and chemical clines that took millennia to assemble respond to a few decades of rapid drying? Can mutualists like pollinators and antagonists like herbivores shift in concert with their host plants, or will phenological mismatches accelerate decline (Morton & Rafferty, 2017)? And as genetic variation for key traits contracts under future climates, what management interventions — seed transfer, habitat connectivity, targeted protection of high-elevation refugia — could help maintain the evolutionary potential of mountain plant communities? The next decade of work at RMBL is poised to tackle these questions by linking long-term demographic monitoring, genomic data, and multi-factor field experiments at scales that match the pace of environmental change.
Aitken, S. N. (2025). An uphill grind for wild plant populations. Science. →
Anderson, J. T. (2017). Climate change affects Boechera stricta genotypes through local maladaptation. →
Anderson, J. T. (2017). The maintenance of flower colour polymorphism in self-pollinating Boechera stricta. →
Anderson, J. T. et al. (2011). Life history QTLs and natural selection on flowering time in Boechera stricta. →
Anderson, J. T. et al. (2013). Genetic tradeoffs and conditional neutrality contribute to local adaptation. →
Anderson, J. T. et al. (2025). Adaptation and gene flow are insufficient to rescue a montane plant under climate change. Science. →
Anderson, J. T., Inouye, D. W., McKinney, A. M., Colautti, R. I., Mitchell-Olds, T. (2012). Phenotypic plasticity and adaptive evolution contribute to advancing flowering phenology in response to climate change. Proceedings of the Royal Society B. →
Anderson, J. T., Panetta, A. M., Mitchell-Olds, T. (2012). Evolutionary and ecological responses to anthropogenic climate change. Plant Physiology. →
Anderson, J. T., Wadgymar, S. M. (2020). Climate change disrupts local adaptation and favours upslope migration. Ecology Letters. →
Anderson, J. T., Willis, J. H., Mitchell-Olds, T. (2011). Evolutionary genetics of plant adaptation. Trends in Genetics. →
Bemmels, J. B., Anderson, J. T. (2019). Climate change shifts natural selection and the adaptive potential of the perennial forb Boechera stricta in the Rocky Mountains. Evolution. →
Carley, L. N. et al. (2021). Ecological factors influence balancing selection on leaf chemical profiles of a wildflower. Nature Ecology & Evolution. →
Carley, L. N. et al. (2025). Increasing aridity may threaten the maintenance of a plant defence polymorphism. Ecology Letters. →
Denney, D. A. et al. (2020). Small spaces, big impacts: contributions of micro-environmental variation to population persistence under climate change. AOB Plants. →
Denney, D. A., Anderson, J. T. (2025). Increased temperature and CO2 induce plasticity and impose novel selection on plant traits. Integrative and Comparative Biology. →
Denney, D. A., Anderson, J. T., et al. (2024). Elevated CO2 and temperature augment gas exchange and shift the fitness landscape in a montane forb. New Phytologist. →
Jameel, M. I. et al. (2025). Herbivory and water availability interact to shape the adaptive landscape in Boechera stricta. Evolution. →
Lee, C.-R. et al. (2017). Young inversion with multiple linked QTLs under selection in a hybrid zone. Nature Ecology and Evolution. →
MacTavish, R. M., Anderson, J. T. (2020). Resource availability alters fitness trade-offs: implications for evolution in stressful environments. American Journal of Botany. →
Morton, E. M., Rafferty, N. E. (2017). Plant-pollinator interactions under climate change: the use of spatial and temporal transplants. Applications in Plant Sciences. →
Wadgymar, S. M. (2015). Plasticity in functional traits in the context of climate change: Boechera stricta. →
Wadgymar, S. M. (2018). Ecological causes and consequences of flower color polymorphism in a self-pollinating plant. →
Wadgymar, S. M. et al. (2017). Identifying targets and agents of selection. Methods in Ecology and Evolution. →
Wadgymar, S. M., Daskin, J. H., Anderson, J. T. (2017). Integrating viability and fecundity selection to illuminate the adaptive nature of genetic clines. Evolution Letters. →
Wadgymar, S. M., Mactavish, R. M., Anderson, J. T. (2018). Transgenerational and within-generation plasticity in response to climate change. American Naturalist. →
Experimental approach where organisms from different source populations are grown in different environments to test for local adaptation
Selection that maintains multiple alleles in a population at frequencies above those expected from mutation alone
Ability of forest ecosystems to maintain function during water-limited conditions through adaptive water use strategies
A process by which adaptive evolutionary change occurs sufficiently rapidly to counteract a decline in population size under initially unfavorable con...
A gradual change in a trait across an environmental gradient, where width is expected to be proportional to dispersal distance divided by square root ...
The study of traits controlled by multiple loci with continuous phenotypic distributions and measurable heritability
When single genes or alleles influence multiple, seemingly unrelated traits
The mechanism by which organisms measure day and night length to regulate seasonal activities like diapause
Statistical approach to identify genetic variants associated with traits by scanning the entire genome
Biochemical pathway producing anthocyanin pigments responsible for purple coloration
An individual locus shows strong adaptive fitness effects in one habitat, but little or no cost in other habitats
Chromosomal rearrangement where a segment is reversed in orientation, potentially suppressing recombination and maintaining linkage between beneficial...
Requirement for extended cold treatment to trigger flowering in some plant species
How plant population density affects individual plant growth, morphology, and susceptibility to herbivory through competition and resource availabilit...
Selection on body mass accounting for juvenile survival until reproduction but may weaken after recruitment
Genetic variation in defensive traits maintained within populations
The proportion of aliphatic GS derived from branched-chain amino acid (Val and Ile) precursors, representing quantitative trait variation controlled b...
Selection pressure from non-biological environmental factors such as rain or wind
The introduction of a species to previously inhabited areas or to new suitable regions
A state where viable seeds do not germinate immediately even under favorable conditions
Conditional Neutrality-Antagonistic Pleiotropy analysis estimates realized selection coefficients and uses permutation tests to identify genome-wide p...
Standardized greenhouse cultivation of field-collected plant accessions under controlled temperature, light, and nutrition regimes for phenotype chara...
Controlled experiment where subjects are not given choices, used to test responses under specific conditions without alternatives.
Chromosome-specific BAC contigs of Arabidopsis thaliana were used as painting probes to analyze mitotic and meiotic chromosomes of C. cordifolia. Fluo...
Sanger sequencing of BCMA3 alleles from natural accessions combined with Nanopore long-read genome assembly to identify structural genetic variants af...
A factorial field experiment manipulating herbivore abundance and water availability using cages with controlled grasshopper access and supplemental w...
Acrylic imprints of leaf surfaces are made on glass slides and analyzed under compound microscope to count stomata and measure their diameters.
Estimation of genetic parameters including heritability and genetic variance-covariance matrices using generalized linear mixed models with Bayesian M...
Hand-pollination experiment comparing fitness of selfed vs. outcrossed offspring by controlling pollination source and measuring resulting fruit chara...
Comprehensive measurement of multiple fitness components including survival, reproductive success, fecundity, and growth rates to assess life history ...
Climate change is expected to alter patterns of species co-occurrence, in both space and time. Species-specific shifts in reproductive phenology may a...
1. Bee pollinators provide a critical ecosystem service to wild and agricultural plants but are reported to be declining world-wide due to anthropogen...
Abiotic and biotic conditions often vary continuously across the landscape, imposing divergent selection on local populations. We used a provenance tr...
It is unclear how environmental change influences standing genetic variation in wild populations. Here, we characterized environmental conditions that...
This file contains phenotypic and fitness data on naturally-recruiting Boechera stricta plants in 5 transects. Jill Anderson collected these data at t...
This file contains phenotypic and fitness data on naturally-recruiting Boechera stricta plants in 5 transects. Jill Anderson collected these data at t...
Fitness trade-offs across episodes of selection and environments influence life-history evolution and adaptive population divergence. Documenting thes...
This file contains data from the experiment at Carpenter Meadow to assess natural selection on flowering in local genotypes. Jill Anderson collected d...
Parental environmental effects, or transgenerational plasticity, can influence an individual’s phenotype or fitness, yet remain underexplored in the c...
This file contains the individual level data for selection analyses and estimates of response to selection in the recombinant inbred lines (RILs) plan...
This file contains family-level average trait values for the recombinant inbred lines (RILs) in the Colorado garden. Columns include: family, leaf num...
data of vouchered bees to test for differences between repeatedly sampled sites and single sample sites regarding abundance functional group compositi...
data of vouchered bees to test for differences between repeatedly sampled sites and single sample sites regarding abundance (as catch rate), rarefied ...
Intraspecific variation in flower color is often attributed to pollinator-mediated selection, yet this mechanism cannot explain flower color polymorph...
Heritable genetic variation is necessary for populations to evolve in response to anthropogenic climate change. However, antagonistic genetic correlat...
data used to calculate mean catch rates per sampling period per year by each sampling method.
sample day by species matrix ready for NMDS analysis.
data of combined bees (vouchered + released) to test for differences between repeatedly sampled sites and single sample sites regarding abundance (as ...
Anthropogenic climate change has already altered the timing of major life history transitions, such as the initiation of reproduction. Both phenotypi...
Fixed chromosomal inversions can reduce gene flow and promote speciation in two ways: by suppressing recombination and by carrying locally favoured al...
In the alpine landscape, characterized by high spatiotemporal heterogeneity and barriers, divergent selection is likely to lead to local adaptation of...
Prof. David Inouye has been collecting data on the abundance and timing of flowers that fall within permanent plots at the Rocky Mountain Biological L...
The role that different life-history traits may have in the process of adaptation caused by divergent selection can be assessed by using extensive col...
Data and scripts for the manuscript "Herbivory and water availability interact to shape the adaptive landscape in the perennial forb, <i>Boechera stri...
Phylogenetic relationships may underlie species-specific phenological sensitivities to abiotic variation and may help to predict these responses to cl...
Data from: "Climate change disrupts local adaptation and favors upslope migration" by Anderson and Wadgymar at Ecology Letters. This folder contains t...
This file contains data on flowering time (first flowering and peak flowering) from 1973-2011 averaged across all plots, as well as snowmelt data and ...
These are data on flowering time (first flowering time and peak flowering time) for all plots from 1973-2011. Data were collected by David Inouye and ...
This file contains data on the timing of snowmelt from 1935-2012, average April-May temperatures from 1973-2011, and minimum April-May temperatures fr...
Data from: "Climate change disrupts local adaptation and favors upslope migration" by Anderson and Wadgymar at Ecology Letters. This folder contains t...
Phylogenetic relationships may underlie species-specific phenological sensitivities to abiotic variation and may help to predict these responses to cl...
These data have been collected by David Inouye almost every year since 1973 at the Rocky Mountain Biological Laboratory.