FUNCTIONAL DIVERSITY OF AVIAN MIXED-SPECIES FORAGING FLOCKS ON THE TILARÁN CORDILLERA, COSTA RICA
DOI:
https://doi.org/10.58843/ornneo.v36i1.1283Keywords:
altitudinal gradient, functional outliers, Monteverde, Neotropics, tropical montane forestAbstract
Avian mixed-species foraging flocks are a common phenomenon in neotropical forests. In order to characterize the variation in such flocks at different elevations, we studied the species composition of avian flocks over a 624 meter elevational gradient on both sides of the continental divide that crosses the Tilarán Cordillera in northwest Costa Rica. We characterized the change in diversity of these flocks across the elevational gradient using several diversity metrics: species richness, functional richness, functional evenness and functional divergence. While the lower elevations of the Atlantic side featured higher species richness, the lower elevations of the Pacific side featured the greatest functional richness and greatest functional divergence. Upper Elevations showed the lowest species richness and lowest functional evenness. A strong understanding of how functional diversity changes with elevation is important in the context of anticipated species altitudinal range shifts with climate change.
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