Contribution of River-Created Habitats to Bird Species Richness in Amazonia

Abstract
A substantial portion (15%) of the non-aquatic avifauna of the Amazon Basin is restricted to habitats created by rivers. These habitats are divided into 6 categories: beaches and sandbats, sandbar scrub, river edge forest, varzea forest, transitional forest, and water-edge. Lists of species restricted to these habitats are presented; for many of these species, this is the 1st published information on habitat preferences. As many as 169 bird species in the lowland neotropics may have evolved in Amazonian river-created habitats, with 99 of these spreading secondarily to man-made 2nd-growth or to regions outside the Amazon Basin. Neither the Congo or Mississippi basin avifaunas show such a high percent of species restricted to river-created habitats; this difference is almost certainly due to the greater amplitude of seasonal water level fluctuations of the Amazon River and its tributaries and consequent greater extent of riverine habits. Alteration of seasonal water flow patterns that would destroy these habitats could potentially exerminate 64 spp. of Amazonian river-created habitat specialists. The use of mist nests to sample bird community composition is discussed.