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Data from: Adaptational lag at high elevations depends on life stage in a California wildflower

Quarles-Chidyagwai, Brandie1; Ashlock, Sarah1; Schmitt, Johanna1; Maloof, Julin1; Gremer, Jennifer1

Published Jun 08, 2026 on Dryad. https://doi.org/10.5061/dryad.ncjsxktbf

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Jun 08, 2026 version files 1.59 MB

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Abstract

High elevation populations are expected to receive reduced snowpack, warmer temperatures, and more variable precipitation with climate change, potentially putting them at risk if rates of adaptation do not keep pace. Populations from climates more closely aligned with changing conditions at high elevations may prove better suited to current climate than the local populations. Thus, it is essential to assess 1) whether high elevation populations are locally adapted to current climate, or 2) whether fitness of lower elevation populations from warmer climates is higher than for local populations in high elevation conditions. We conducted a common garden study with Streptanthus tortuosus at a high elevation site. Plants from twenty-three populations from across the species range, which vary in climate and life history, were transplanted and subsequently measured for mortality and reproductive output across two growing seasons. We examined the effects of climatic distance from the site of origin on plant performance. We hypothesized that lower elevation populations would survive the first warm growth season well, but the seasonal constraint of cold temperatures and snowpack would reduce their survival into the second year, thus limiting their overall fitness. We observed evidence for adaptational lag for high elevation populations, including the local population, but only for some life stages. Lower elevation populations, with climates further from the garden, had higher survival through the first year and over winter, resulting in higher probabilities of reproducing and total fitness. However, survival to reproduction in year 2, and total reproductive output, driven largely by reproduction in the second year, were higher in high elevation populations, with climates closer to the garden. Thus, adaptational lag differed among life stages, and depended on life history (e.g., first year versus second year fitness). Our results highlight the importance of considering variation in life history and seasonal timing when evaluating climate adaptation, as well as vulnerability of high elevation populations to climate change. Further, these findings provide information for management of populations at risk, including strategic assisted gene flow that introduces beneficial alleles from warm-adapted populations but preserves some components of high elevation adaptation.