Population history explains the performance of an annual herb - within and beyond its European species range

1. The centre-periphery hypothesis (CPH) predicts a decrease in population performance from the centre of the species range towards the edge, hindering further species expansion. To overcome ecological limitation, local adaptation of peripheral populations is assumed necessary to extend niche space and thus to potentially facilitate species’ range expansion. However, adaptive changes do not necessarily correspond to current ecological marginality. Instead, population history may provide a fuller context for understanding patterns of local adaptation within the species range. Here, we test whether local adaptation to current conditions or population history explains current species distribution in an annual heterocarpic species, Atriplex tatarica, in Europe.
2. The ecological marginality and population history were estimated using species distribution modelling (SDM) and 13 microsatellite markers. To test for local adaptation, we evaluated the population performance of both currently ce...