Effects of fragmentation on parasite burden (nematodes) of generalist and specialist small mammal species in secondary forest fragments of the coastal Atlantic Forest, Brazil
Parasites are considered to play an important role in the regulation of wild animal populations. We investigated parasite burden of gastrointestinal nema- todes and body condition in specialist and generalist small mammal species in secondary forest fragments in the highly endangered coastal Atlantic Forest. We hypothesized that body condition decreases with increasing parasite load and that parasite burden in- creases with increasing fragmentation in specialist spe- cies but not in generalist species as a consequence of differing responses to fragmentation effects. Investigated species were Akodon montensis, Oligoryzomys nigripes, and Delomys sublineatus (rodents) and the marsupials Marmosops incanus and Gracilinanus microtarsus. Prev- alence of parasites was high in all species except for the arboreal G. microtarsus, presumably because of de- creased infection probability. No correlation was found between body condition and parasite load in any of the species. Contrary to our expectations, body condition of the specialists D. sublineatus andM. incanus increased in both species with increasing fragmentation. In D. sub- lineatus, parasite burden increased and body condition decreased in fragments with relatively high density probably due to increased contact rates and facilitation of infection with nematodes. In all generalist species, low or no correlation between parasite burden and frag- mentation was detected, suggesting little effect of frag- mentation on population health.