Amazonian ecology: Tributaries enhance the diversity of electric fishes

摘要: Neotropical rivers support a diverse array of endemic taxa, including electric fishes the order Gymnotiformes. A comprehensive survey main channels Amazon River and its major tributaries (>2000-kilometer transect) yielded 43 fish species. Biogeographical analyses suggest that local mainstem diversity is enhanced by tributaries. Mainstem species richness tends to increase downstream tributary confluences, composition most similar between adjacent locations. These findings “nodal” or heterogeneous model riverine community organization across particularly extensive geographical region.