Local adaptation-induced evolutionary trap in alpine plants under climate change

Abstract

Abstract Evolutionary traps occur when populations deviate from local adaptation and become maladapted under rapid climate change. Alpine plants, with genetically distinct ecotypes in sky islands, are susceptible to being trapped by rapid climate change. We employed landscape genomics to test a local adaptation-induced evolutionary trap in the alpine perennial plant Roscoea tibetica (Zingiberaceae) with three distinct ecotypes along altitudinal gradients in the Hengduan Mountains. Strong local adaptation to alpine environments was observed through isolation-by-environment and rapid decreases in effective population size following interglacial niche contraction. Genomic offset increased with climate warming and was positively correlated with the intensification of local adaptation. Instead of high-elevation ecotypes, an evolutionary trap was indicated in the low-elevation forest ecotype, which showed the strongest local adaptation and niche loss, requiring the greatest shift in allele frequencies to keep pace with future climate change, and will likely experience the largest population decline. Therefore, stronger local adaptation induces evolutionary traps more easily and aggravates the harm to alpine plants facing rapid climate warming. Our study provides the first empirical case of local adaptation-induced evolutionary traps for alpine plants and highlights that it is crucial for alpine biota conservation to consider and disarm evolutionary traps under climate change.