Ant taxonomic and functional beta-diversity respond differently to changes in forest cover and spatial distance
Ingrid Santos Martins, Jean Carlo Gonçalves Ortega, Vinícius Guerra, Marília Maria Silva da Costa, Felipe Martello, Fernando Augusto Schmidt
Abstract
Habitat change affects both taxonomic and functional biodiversity, and beta-diversity is often used as a metric to describe these changes. Furthermore, spatially closer communities tend to have more similar species compositions (lower beta-diversity). These changes in community composition can be revealed with taxonomic and functional aspects of diversity. We assessed the responses of ant taxonomic and functional beta-diversity to changes in forest cover and spatial distance. We expected that changes in taxonomic and functional beta-diversity along a forest cover gradient would be caused by the replacement of open-habitat ant species by forest-habitat ant species. We sampled ants within twelve landscapes with different forest cover percentages in the southwestern Amazon of Brazil. Both taxonomic and functional beta-diversity of pairwise samples (βBC) were partitioned into their turnover (βBal) and nestedness (βGra) components. Increasing forest cover correlated with increases in taxonomic and functional βBC, however, βBal had a greater contribution to taxonomic βBC and βGra to functional βBC. Taxonomic βBC and βBal and functional βBal increased with spatial distance. Forest-habitat species richness increased, and open-habitat species richness decreased with increasing forest cover, while the richness of habitat-use generalist species did not vary. The loss of environmental heterogeneity may be responsible for generalist species dominance and open-habitat species presence in less-forested landscapes. This leads to great taxonomic replacement, but a nestedness gradient of function. Better land use planning is needed to ensure biodiversity and ecosystem functions of forest habitats in human-modified landscapes.