Birds of the Land of Swallows: Contribution of the Main Ecosystems of Cozumel Island to Its Avian Diversity

Abstract

Caribbean islands are important hotspots for endemic species, concentrating high biodiversity on exceptionally small areas. Cozumel Island is not an exception, yet little published information exists on its bird diversity. In this study, we assessed the contribution of each major ecosystem of Cozumel Island (i.e., tropical forest, mangrove, palm thicket, and urban setting) to the island's avian diversity. Avian richness was highest in tropical forests, followed by mangroves, palm thickets, and urban setting. Bird densities were highest in urban settings, followed by tropical forests, mangroves, and palm thickets. Species composition similarity among ecosystems was low, with the most dissimilar ecosystem being the urban setting. Interestingly, we recorded the highest number of unique species in mangroves, followed by tropical forests, urban settings, and palm thickets. Tropical forests and mangroves of Cozumel Island are the main ecosystems harboring high avian diversity, with tropical forests housing high avian densities and endemics and mangroves including the most unique species. As expected, the contribution of urban settings to the avian diversity of Cozumel Island is limited and includes some highly abundant invasive species, of which the Eurasian Collared-Dove could represent a major ecological threat.