Diet specialisation reduces the occupancy of cocoa agroforests by diurnal raptors

Abstract

SummaryHabitat loss and fragmentation, especially due to agriculture expansion, pose the main threats to biodiversity conservation. While some species are able to survive and proliferate in human-modified habitats (winner species), others are highly dependent on well-preserved habitats, being more vulnerable to extinction (losers). Many raptors can be considered loser species due to their high trophic position, large home ranges, and low reproductive rates. Consequently, this group is frequently used to reflect the environmental quality of habitats and the biodiversity status of communities. Here we describe the diurnal raptor assemblages found in shaded-cocoa agroforests (cabrucas) of Southern Bahia, Brazil, and the determinants of raptor occupancy in this system. We systematically surveyed diurnal raptors in 16cabrucasites using complementary sampling methods – active search, playback, and point-count – and modeled species occupancy using covariates related to vegetation structure, landscape, management intensity, and biological traits (body mass, trophic level, and diet specialisation). We found a high number of species (at least 18) as able to usecabrucasand a negative relationship between species occupancy and the degree of diet specialisation. Thus, our results suggest thatcabrucashave a high potential to mitigate the effects of forest loss and fragmentation on diurnal raptors, but this system alone may not support complete assemblages of this group. It highlights the need for the maintenance of forest remnants in the landscapes to increase species diversity at a regional scale and to assure the conservation of this group in Southern Bahian Atlantic Forest.