PLANT PERFORMANCE ACROSS LATITUDE: THE ROLE OF PLASTICITY AND LOCAL ADAPTATION IN AN AQUATIC PLANT

TLDR

Geographic variation drives the evolution of distinct local varieties, shaping species distribution and genetic structure. The study examined how plasticity and local adaptation influence the performance of Potamogeton pectinatus across contrasting climates by conducting reciprocal transplants at three European sites along a latitudinal gradient. A reciprocal transplant experiment involved 54 genets from 14 populations spanning four climatic regions, which were grown in three localities (Norway, the Netherlands, and Spain). Tuber production was highest in mild‑temperate genets at all sites, central populations outperformed peripheral ones, and marginal populations showed life‑history shifts (compressed cycles in the north, perenniality in the south) that may improve local performance, suggesting that local adaptation aligns with center‑periphery performance gradients driven by genetic drift and inbreeding.

Abstract

Geographic variation can lead to the evolution of different local varieties within a given species, therefore influencing its distribution and genetic structure. We investigated the contribution of plasticity and local adaptation to the performance of a common aquatic plant (Potamogeton pectinatus) in contrasting climates, using reciprocal transplants at three experimental sites across a latitudinal cline in Europe. Plants from 54 genets, originally collected from 14 populations situated within four climatic regions (subarctic, cold temperate, mild temperate, and mediterranean) were grown in three different localities within three of these regions (cold temperate, Norway; mild temperate, The Netherlands; mediterranean, Spain). Tuber production was highest for the mild-temperate genets, irrespective of locality where the genets were grown. Selection coefficients indicated that populations at the European center of the species distribution perform better than all other populations, at all sites. However, marginal populations showed changes in life-history traits, such as compressed life cycles in the north and true perenniality in the south, that may allow them to perform better locally, at the limits of their distribution range. Our results thus suggest that local adaptation may overlap spatially with center–periphery gradients in performance caused by genetic factors (such as genetic drift and inbreeding in range-marginal populations).