Vortrag, 43. Jahrestagung der Gesellschaft für Ökologie (GfÖ), Potsdam: 09.09.2013 - 13.09.2013
The factors driving speciation and therefore endemism on regional scales are still largely unknown. Patterns and drivers of endemism are best studied on islands where most endemic species can be assumed to result form in situ speciation. Distinct patterns and their dependence on environment are optimally studied in the presence of steep environmental gradients and complex topography. Accordingly, we collected data of single island endemic plant species (SIE) in almost 2000 sampling sites on La Palma, Canary Islands (max. elevation of 2426 m) and combined them with high-resolution (i.e. 100 x 100 m) climatic, geological, land use, elevation and other environmental data. Ensemble modeling was used to calculate the spatial distribution of each SIE species and then combined to measures of richness distribution. SIE richness varied strongly within the island with the highest numbers found in the steep northern coastal areas, while lowest values were associated with recent volcanic activity on the southern tip of the island. The percentage of SIEs increased with elevation and was negatively correlated with precipitation. This can be interpreted as an increase of diversification rate with elevation. This large dataset contains an unprecedented spatial resolution (almost 3 sampling sites per km2) and quality and is therefore highly valuable for species distribution modeling approaches. Thus, further questions associated with the effect of climate change on endemic plant species or differences in niche size between species groups can be effectively tested.