Low-Intensity Landscaping of Research Facilities Increased Taxonomic, Functional and Phylogenetic Bird Diversity in a Lowland Rainforest

Summary. Bird communities inhabiting tropical rainforests are sensitive to changes in vegetation structure, either natural (e.g. treefalls or landslides) or man-made. Natural changes tend to increase diversity and abundance, whereas anthropic changes often have the opposite effect. We analyse how landscaping for the creation of research facilities influenced the taxonomic, functional and phylogenetic diversity of bird communities in a Caribbean coastal rainforest of Costa Rica, and whether diversity changes were mediated by changes in vegetation structure. Bird communities were sampled by means of mist nets located in the landscaped areas and in paired sites of the nearby rainforest during three consecutive dry seasons (2017-2019). Vegetation structure around each net was also recorded. Forest openness and degree of development of the tree layer led to more abundant and species-rich assemblages in both the managed and the non-managed sites. Functional diversity of several key traits (diet, beak shape, manoeuvrability and foraging site) was favoured by the degree of development of the tree layer in managed sites and by those of the shrub layer in the forest. Beta diversity analyses showed that increased diversity in managed areas was due to a higher presence of species linked to naturally cleared forest areas already present in the forest, rather than to a substitution of a species-poor forest assemblage by a species-rich open-land community. Overall, we show that low-intensity disturbance linked to the creation and maintenance of research facilities can favour the conservation of richer and functionally diverse bird communities, at least in species-rich secondary rainforests, as long as a well-developed tree layer is maintained in the cleared areas.—Aycart, P. & Díaz, M. (2021). Low-intensity landscaping of research facilities increased taxonomic, functional and phylogenetic bird diversity in a lowland rainforest. Ardeola, 68: 355-371.