Vegetation structure and bird diversity in silvopastoral systems of the Amazonian piedmont of Colombia

The department of Caquetá in the Amazon foothills of Colombia is one of the most dynamic in terms of cattle production in the country. Thousands of hectares have been replaced by pasture monoculture with negative consequences for the biodiversity. Silvopastoral systems (SPS) have been promoted in the region as an alternative to improve tree cover, biodiversity and productivity of cattle farms. To analyze the impact of SPS on plant and bird diversity, 22 plots with three silvopastoral arrangements (tree alleys: TA, scattered trees in pastures: STP, intensive silvopastoral systems: iSPS) and pasture monocultures (PM) were sampled using 20 × 50 m quadrats for vegetation and 50 m radius fixed points for birds. A total of 556 individuals of 26 families and 60 plant species were found. TA and STP had significantly higher abundance and richness of vegetation than PM. For bird fauna 2209 individuals belonging to 18 orders, 42 families and 149 species were present. Bird diversity and abundance were significantly higher in TA than PM. The diversity and abundance of plants, as well as vegetation structure had a positive and significant effect on the abundance and richness of birds, and on the richness of frugivorous, insectivorous, and omnivorous birds, and the richness of species with preferences for different habitats. Plant diversity and structure complexity is key to improve diversity of birds, frugivorous and insectivorous species and therefore should be considered when selecting plant species to be introduced in the cattle systems.