Avian functional diversity across the neotropics: current knowledge and perspectives

The value of birds as indicators of environmental change is of greater relevance given the current rapid habitat loss and transformation rates. This is no more important than in the megadiverse Neotropical realm, which is experiencing accelerated biodiversity loss. Evaluation of the ecological role or functional diversity of avian communities is rapidly replacing traditional indices of species diversity and bird abundance, but there is a dearth of functional diversity studies in the tropics. We searched for relevant literature on Google Scholar and Scopus databases to assess the current scientific knowledge on the functional dimensions of bird communities within the Neotropics. We built a database of 66 studies to generate infometrics as a reference baseline for future studies. The majority of studies on avian functional diversity in the Neotropics were published in the last five years (2019–2023). Most research has been conducted in Brazilian forests, leaving the remaining Neotropical countries and habitats underrepresented. Functional richness and functional dispersion were the most frequent indexes across studies. Most studies compared functional diversity among habitats or habitat conditions or evaluated functional diversity index in response to environmental variables. We encourage researchers to objectively select the functional traits and functional diversity indices used in their studies, and explicitly state their relevance to the research question. Re-analysis of existing data, and collaboration among researchers within the Neotropics, should enhance the development of the functional diversity field for the understanding of bird assemblage patterns and processes, but also to achieve effective process-focused conservation strategies.