Predicting patterns of plant species richness in megadiverse South Africa

摘要: Using new tools (boosted regression trees) in predictive biogeography, with extensive spatial 23 distribution data for >19 000 species, we developed models South African plant species richness patterns. Further, biome level analysis explored possible functional determinants of country-wide regional richness. Finally, to test model reliability independently, predicted potential alien invasive an independent dataset. Amongst the different hypotheses generally invoked explain 30 diversity (energy, favorableness, topographic heterogeneity, irregularity and seasonality), results revealed heterogeneity as most powerful single explanatory variable indigenous Some biome-specific responses were observed, i.e. two five analyzed biomes (Fynbos Grassland) had best explained by “species-favorableness” hypothesis, but even this case, was also a primary predictor. This analysis, largest conducted on almost exhaustive sample species-rich region, demonstrates preeminence shaping pattern Model confirmed considerable power It thus appears that controls main ways: firstly, providing abundance ecological niches contemporary space (revealed relationships) secondly, facilitating persistence through time. The extraordinary Fynbos biome, world-renowned hotspot biodiversity steepest environmental gradients Africa, may have arisen both mechanisms. Comparisons similar regions world outside Africa are needed confirm generality favorableness predictors