A subalpine forb's response to natural and experimental climate variation

In light of both molecular and ecological evidence that evolutionary change can happen over short time scales, many now acknowledge that adaptation could play an important role in species-level responses to climate change. Working out of the Rocky Mountain Biological Laboratory (RMBL) (http://www.rmbl.org/rockymountainbiolab/), we test the hypothesis that adaptation plays a role in a montane forb’s response to both experimental warming and climatic variation across elevations. Our focal organism, Androsace septentrionalis (Primulaceae, Figure 1), is a locally abundant, short-lived, highly selfing forb that spans a natural elevation gradient of 2500m to 4811m. Our study sites include six populations, two at high (3733m), mid (3186m), and low (2933) elevation sites. One of our mid-elevation populations is located in RMBL’s Warming Meadow, a series of five heated and five control plots. Since 1991, the Warming Meadow has yielded control and heated plot data on vegetation productivity, phenology, community structure, soil microclimate, and biogeochemistry. Over the past three years, we have marked, monitored, and collected seed from A. septentrionalis across both warmed and natural field sites. Here, we highlight how A. septentrionalis’ life history, morphology, and phenology vary across high, mid and low elevation, and we discuss how these results inform our hypotheses about adaptation in response to experimental warming. We also document the effects of twenty years of experimental warming on A. septentrionalis abundance, distribution, phenology, and fitness. Finally, we discuss two ongoing experiments that will help us determine: 1) how selection varies across heated and control plots and across moisture gradients within each plot: 2) whether or not we can detect adaptation in response to twenty years of experimental warming: and 3) what roles are played by plastic and genetic responses to different climatic regimes. By combining the cumulative results of a long-term climate manipulation experiment with reciprocal transplants and common gardens, we hope to understand the role that local adaptation plays in species-level responses to global climate change. Figure 1: Androsace septentrionalis