Spatially explicit analysis of gastropod biodiversity in ancient Lake Ohrid

摘要: Abstract. The quality of spatial analyses biodiversity is improved by (i) utilizing study areas with well defined physiogeographical boundaries, (ii) limiting the impact widespread species, and (iii) using taxa heterogeneous distributions. These conditions are typically met ecosystems such as oceanic islands or ancient lakes their biota. While research on has contributed significantly to our understanding evolutionary processes, statistically sound studies variation extant have been hampered frequently vast size lakes, limited accessibility, lack scientific infrastructure. European Lake Ohrid provides a rare opportunity for reliable study. comprehensive horizontal vertical sampling species-rich taxon, Gastropoda, presented here, revealed interesting patterns biodiversity, which, in part, not shown before other lakes. In total 284 samples from 224 different locations throughout Basin, 68 gastropod 50 them (= 73.5%) being endemic, could be reported. distribution these species shows following characteristics: within Ohrid, most frequent endemic wide depth range, (i.e. those occurring Balkans beyond) mainly occur upper layer lake, while number decreases water depth, proportion endemics increases, (iv) deeper layers appear higher homogeneity biodiversity. Moreover, communities its feeder springs both distinct each surrounding waters. analysis also that community similarity driven niche processes (e.g. environmental factors), but neutral dispersal limitation histories species). For niche-based mechanisms it large scale effects type body responsible communities, whereas small like gradients affect compositions only marginally. fact, more important than factors, thus emphasizing importance capacities species.