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Seasonality of the bird community in the Tumbesian dry forest in south west Ecuador

Abstract:

The Tumbesian region is of global priority for biodiversity conservation due to the high levels of endemism. Despite this fact, the knowledge about avian communities is particularly deficient. A main environmental characteristic of the region is an extremely seasonal rain pattern, which leads to two highly pronounced weather seasons: wet and dry. The aim of this research was to characterize the structure and composition of the bird community during the two weather seasons in La Ceiba reserve, located in southwestern Ecuador. In nine months during the year 2003, bird censuses were performed using microtransects. A detrented correspondence analysis revealed that the bird assemblage was strongly influenced by seasonal rain, showing a gradient in the position of the months, from rainy to dry months. The wet season had a greater species richness supported by a species accumulation curve and the Chao 2 statistics; this pattern is similar to what has been found in other tropical dry forests habitats. Insectivorous and omnivorous species were more abundant in the wet season, which could be related to seasonality in food resources. Intratropical migrant bird species comprised an important component of the avian assemblage, which affects conservation planning within the Tumbesian region in that some level of habitat connectivity is required to facilitate the dispersal of birds in this severely disturbed region. © The Neotropical Ornithological Society.