Riparian Mesquite bushes are important for bird conservation in tropical arid Mexico

Abstract

Riparian habitats are important sites for avian conservation in western North America. These sites are also places of increasing human exploitation due to water availability and vegetation composition. Degradation and habitat patchiness of these systems may cause declines in avian species that are obligate breeders or use these habitats as corridors during migration. Our objective was to examine species composition and diversity of birds inhabiting a patchy Mesquite landscape in central Mexico. The study was conducted in the Salado River watershed in the Tehuacán-Cuicatlán Biosphere Reserve. We conducted bird censuses using circular plot surveys in four zones of similar size differing mainly in proximity to town. We compared bird presence and density with plant coverage and density measured at the same points. We recorded 80 bird species, 53.6% of which were winter migrants. The four zones studied were not statistically different in bird species composition but differed in bird densities. Points counted inside the zones differed in bird densities and were positively correlated with plant density. The study site can be considered important for bird conservation due to its bird species richness, migratory species found exclusively in riparian habitat, and the presence of resident endemic species that breed in the area. Vegetation clearance that involves partial reduction of plants can represent a threat to bird conservation in the area.