Padrões de distribuição geográfica de aves associadas ambientes alagáveis da Amazônia

Abstract

With the objective of characterizing the patterns of endemism and diversity for birds specialized in floodplain environments in Amazonia, we employed a database of occurrence records, including 26,515 georeferenced occurrence records for 70taxa. The data set was analyzed employing two approaches that use different logical bases to identify patterns of co-occurrence of species, and thus verify the congruence of the recovered patterns: endemicity analysis (EA) implemented in the NDM software, and Infomap Bioregions. To define diversity distribution patterns, we identified changes in species composition using the Species Composition Interpolation (SCI) function, implemented in the environmental modeling platform, EGO Dynamics.This function analyzes Beta diversity patterns in space through hexagons and interpolation, which identifies the most significant changes in the spatial distribution of a dataset. Our multi-analytical approach recovered3, 7 and 14 areas in spatial resolutions of 2º, 3º and 4º, respectively in the NDM analyses, and six bioregions using Infomap Bioregions. Our diversity analysis showed three distinct compositional patterns, one to the north of the Amazon River, the other to the east, including the Tapajós, Xingu and Tocantins basins, and finally a region encompassing the main course of the Amazon and tributaries to the west-northeast of the Amazon Basin. We provide the first quantitative analysis of endemism and species diversity for birds specialized in seasonally flooded Amazonian environments. Our results revealed spatially complex patterns of endemism and diversity for birds in floodplain environments with areas of varying degrees of overlap, nesting, and disjunction.In general, the areas of endemism identified are associated with the three main basins of the northern portion of South America, the Amazon Basin, the Tocantins Basin and the Orinoco Basin.Taxa identified as endemic to these areas comprise 28 % (70) of avian taxa dependent on flooded systems. Of these, two are considered threatened (NT and VU) and two have not yet been evaluated by IUCN and BirdLife International.