Livestock areas with canopy cover sustain dung beetle diversity in the humid subtropical Chaco forest

Abstract

We assessed differences in the alpha and beta diversity of dung beetles in native forest and two livestock systems (with and without canopy cover) typical of the Argentine Chaco region and related the dung beetle assemblages to environmental conditions. Dung beetles were sampled in native forest and two livestock systems in the spring (2015-2016), in two areas of the humid Chaco region in northern Argentina. In each area, five sampling sites were selected for each habitat type, and ten pitfall traps were baited with human faeces and carrion and placed at each site. The livestock systems with canopy cover preserved the environmental conditions from the native forest (temperature and vegetation structure) and the richness and composition of the native forest dung beetle community in the two areas studied, whereas the open pastures exhibited higher ground temperature, simplified vegetation structure and lower dung beetle richness and similarity in species composition in relation to the native forest. In livestock systems of the humid Chaco, the canopy cover is the main determinant of dung beetle communities through the maintenance of temperature and humidity. In the light of these results, livestock production in silvopastoral systems preserving canopy cover can be an alternative compatible with conservation of the dung beetle diversity of native forests. Considering the central role of dung beetles in maintaining soil structure and fertility (through the relocation of cow dung), silvopastoral systems will probably maintain the productivity compared to open pastures.