Future geographic patterns of novel and disappearing assemblages across three dimensions of diversity: A case study with Ecuadorian hummingbirds


Under climate change, it is likely that as species reshuffle based on their environmental tolerances, novel assemblages will form and some current assemblages will disappear. It is important for future monitoring and conservation that we understand where these novel and disappearing assemblages occur and how they differ among dimensions (taxonomic, phylogenetic and functional) of diversity. Here we investigate the geographical and environmental patterns of novel and disappearing assemblages; whether these patterns hold across dimensions of diversity; and how these assemblages are characterized in trait space. We used ensemble species distribution modelling to estimate the distributions of 151 hummingbird species into the projected climate for 2070. Using standard beta diversity measures, we identified novel and disappearing taxonomic, phylogenetic and functional assemblages. We found that novel and disappearing hummingbird assemblages are likely under climate change, particularly in extreme environments and with novel assemblages replacing disappearing assemblages. Although the patterns of novel and disappearing assemblages were similar among dimensions of diversity, we found that there were fewest novel and disappearing functional assemblages. The future assemblages were characterized by an increase in functional space, which is counter to typical predictions of trait homogenization under climate change. Novel and disappearing assemblages are likely to pose management challenges for future conservation. Here we present an approach to identify such assemblages. By considering the geographic and environmental context of novel and disappearing assemblages for different dimensions of diversity, we can start to identify the mechanisms behind these patterns.

Diversity and Distributions, (23), pp. 944–954, https://doi.org/10.1111/ddi.12587