Parallels and divergences in landscape genetic and metacommunity patterns in zooplankton inhabiting soda pans

Ecological processes maintaining landscape genetic variation and metacommunity structure in natural landscapes have traditionally been studied in isolation. Their integrated study may hold important information as to what extent the effect of major ecological processes are species- or landscape-specific, resulting in a more coherent picture on the spatial organization of biodiversity. Here, we explicitly compared the relative importance of spatial and environmental drivers of both cladoceran metacommunity structure as well as landscape genetic structure of its most widespread member, the water flea Daphnia magna, in soda pans of the Seewinkel region in Austria. The landscape of soda pans in this region is characterized by strong environmental gradients and unidirectional wind acting as a key dispersal agent among these temporary habitats. Our study shows both parallels and divergences in the relative importance of local environmental sorting and spatial connectivity in determining landscape genetic versus metacommunity structure. The metacommunity is structured primarily by the environment, while in the D. magna metapopulation, the spatial signal is predominant. The much weaker environmental signal in Daphnia can be explained by the fact that the microsatellite markers are presumably neutral and was confirmed by a per-allele analysis. An important parallel between metacommunity and landscape genetic structure is the strong signal of the prevailing wind direction in determining the spatial pattern. This suggests that for both community as well as population assembly in D. magna, wind plays an important role in determining connectivity among soda pans, thereby affecting dispersal and colonization rates influencing both local species and genetic composition.