Dung beetles in continuous forest, forest fragments and in an agricultural mosaic habitat island at Los Tuxtlas, Mexico

With the aim of determining what kind of landscape mosaics might sustain maximum diversity and minimum species loss, dung beetles were sampled with baited pitfall traps to compare species richness and species composition in a tract of continuous forest, forest fragments and a habitat island consisting of a mosaic of forest and arboreal crops in Los Tuxtlas, southern Mexico. We captured 7332 dung beetles representing 33 species. Similar numbers of species were captured in the three habitats. However, 56% of individuals were captured in the continuous forest, 29% in the mosaic habitat and 15% in the forest fragments. Eight species (Canthon femoralis, Copris laeviceps, Canthidium centrale, Onthophagus batesi, Deltochilum pseudoparile, O. rhinolophus, Canthon viridis vazquezae and Dichotomius satanus) accounted for 90% of the captures, but their relative dominance varied among habitats. A clear trend was evident in the number of dung beetles captured in the dung processing guilds (rollers / tunnelers) as well as in the diurnal and nocturnal guilds, with captures decreasing from the continuous forest to the mosaic habitat to the forest fragments. A similar trend was detected in detection rates for medium and small size dung producing mammals. Species richness of forest fragments and mosaic habitat did not differ from that found in the continuous forest, but these habitats differ significantly in species richness from isolated shaded and unshaded plantations, linear strips of vegetation, the forest-pasture edge and pastures according to rarefaction analysis. The co-occurrence of the continuous forest, the mosaic habitat and the cluster of forest fragments in close proximity seems to be preserving a diverse assemblage of dung beetle species in the local landscape.