Morphometry and diversity of birds in cocoa agroforestry and silvopastoral systems in the Colombian Amazon

Abstract

The primary cause of deforestation in the Amazon region is extensive traditional cattle ranching, which is considered an important economic activity in several departments of the region, particularly in Caqueta. This research aimed to determine the influence of vegetation cover on the morphometry and diversity of birds in agroforestry systems with cocoa and silvopastoral practices in the Colombian Amazon. Sampling was conducted in eight locations in the Caqueta department using mist nets between January and November 2023. In each location, five effective sampling days were carried out, and for each captured individual, weight and morphometric measurements of the bill, wings, legs, and tail were recorded. Based on the wing measurements, the Kipps index was calculated, relating the morphology to the dispersal capacity of the birds. A total of 350 individual birds were recorded, distributed across 77 species and 20 families in the sampled agroforestry systems with cocoa and silvopastoral practices. The Early Brush cover type exhibited the highest richness and abundance, and it was determined that the variation in the morphometric traits of the birds is associated with the type of habitat. The species accumulation curve from the collected mosaics allowed for the documentation and analysis of community richness in these two systems. It was determined that agroforestry systems with cocoa and silvopastoral practices, due to their tree structures simulating a heterogeneous habitat, have the capacity to host many species and are therefore important for the conservation of avifauna. Anthropization and fragmentation of natural habitats exert pressures on birds, leading to modifications in their morphometric traits to adapt to their environmental conditions.