Disentangling spatial and environmental determinants of fish species richness and assemblage structure in Neotropical rainforest streams

摘要: Freshwater ecology templates were developed in temperate streams, but whether they also apply to tropical streams that harbour a higher biological diversity than their counterparts remains uncertain. This is particularly true for fish assemblages inhabiting small have been less studied larger, higher-order lowland streams. Here, we disentangled the strength of spatial (longitudinal and environmental) drivers, scale-specific (drainage basin, reach local scale) determinants species richness composition freshwater French Guiana. We found increased from upstream downstream with increasing habitat structural independently stream position upstream–downstream gradient. pattern was shared by two most speciose orders (Characiformes Siluriformes), demonstrating addition rather replacement shaped these assemblages. Species determined equally structure within drainage environment, differed both distance along an The environmental effect on indicated fact almost all descriptors had slight nonetheless significant effects assemblage composition, probably reflecting species-specific responses environment. In contrast, despite strong micro-endemism between drainages some taxa, only slightly affected river identity, since widespread common constituent rivers. We identified five characterising different features torrential areas muddy areas. We distinguished confluence larger rivers, which other assemblages. zonation patterns report can constitute benchmark future studies measuring impact anthropogenic disturbances Neotropical forest streams.