The biotic interactions hypothesis partially explains bird species turnover along a lowland Neotropical precipitation gradient

摘要: AIM: We evaluated the influence of climate on structure bird communities along precipitation gradients. hypothesize that mechanisms responsible for community turnover gradients are similar to operating temperature and latitudinal tested hypothesis environmental conditions affect composition in dry forests, whereas biotic interactions wet forests. LOCATION: Low‐elevation forests a gradient Colombia where ranges from 700–4,000 mm annually but elevation remain constant. TIME PERIOD: Present day. MAJOR TAXA STUDIED: Neotropical forest birds. METHODS: sampled at 291 points nine study areas (localities) across c. 3,000‐mm range. In each locality, we obtained climatic characteristics phylogenetic, morphological physiological proxy data test predictions about evolutionary relationships distribution traits. RESULTS: Bird changed abruptly differed between Analyses phylogenetic relationships, trait space, observations nests suggested filtering is more important than especially breeding. contrast, found little evidence competition was Nest predation or nest however, may be critical wetter CONCLUSIONS: The two distinct documented suggest lowland gradients, which constant, can as generating high beta diversity. conclude breeding might crucial determining assembly Given recent population declines tropical birds have been attributed changes precipitation, by understanding underlying our improve ability understand those predict effects change avifauna.