Climate and site-specific factors shape chironomid taxonomic and functional diversity patterns in northern Patagonia

Abstract

Functional richness patterns of lake chironomid assemblages have been increasingly studied in the Northern Hemisphere, but so far there are no studies in Southern Hemisphere lakes. Present-day chironomid assemblages were studied from 40 lakes in NW Patagonia to investigate functional and taxonomic diversity and its relationships with the environment. Using multiple regression analysis involving climate-related and site-specific variables, we found that water temperature and terrestrial vegetation cover were the main drivers affecting chironomid taxonomic richness and diversity. Functional richness was explained only by vegetation cover variation, and functional diversity was not explained by any of the predictor variables. Our results contrast with previous findings in the Northern Hemisphere showing that taxonomic and functional diversity measures provide similar information on community and ecosystem function. In Patagonian lakes, taxonomical diversity analysis is still more helpful to understand the relationships between chironomid assemblages and environment, which remarks the needs for further ecological studies on Chironomidae in the area. Regardless, this is the first study to investigate chironomid functional groups in relation to the environment and their distribution in austral lakes.