Changes in ground-foraging ant assemblages along a disturbance gradient in a tropical agricultural landscape

Changes in ground-foraging ant assemblages occurring along an agricultural intensification gradient were analysed in Nicaragua (Central America). Five habitat types were compared: secondary forest fragments, organic shade coffee and cocoa plantations, corn fields and active pastures. Ants were captured by tuna baiting following standardised protocols. Species richness and diversity decreased along the gradient from forest to the pasture, and each of the agricultural systems (cocoa, coffee and corn plantations) significantly differed in diversity. Species composition also differed along the disturbance gradient, as shown by multivariate analysis. Forest and pasture were at the extremes of the gradient and shared no common species. The ant assemblages associated with coffee plots, although poorer in species, were more similar to those of the forest than to those of the cocoa plantations. The observed trends confirm that shaded agro-forestry plantations can help to maintain high biodiversity levels in tropical landscapes.