Using high-resolution remote sensing data for habitat suitability models of Bromeliaceae in the city of Mérida, Venezuela

Little information is available concerning the effects of the increasing urbanization on biodiversity in tropical regions. Species distribution modelling based on interpolated climate data is a widely applied, time- and cost-effective tool to estimate the potential species richness in a target area. However, high fragmentation, strong environmental gradients on a small-scale, and lack of fine-scale environmental data in tropical urban areas require alternative approaches. In this study we combined a rapid species assessment approach with environmental niche modelling based on high-resolution ASTER satellite imagery to predict species distributions of Bromeliaceae in the city of Mérida, Venezuela. Twenty species of Bromeliaceae, e.g. 36% of the total bromeliad diversity of the state of Mérida, were observed in the city, including seven species with CAM physiology. CAM species showed significantly higher occurrence probabilities in zones with higher soil sealing, whereas in C3 species a trend across soilsealing zones was not observed. The remarkable urban species richness of Bromeliaceae is here attributed to the species' different adaptive strategies, as well as to the strong elevation gradient of Mérida city. Our species modelling approach provides new possibilities for the identification of indicator species in different urban built-up areas.