Effect of Forest Cover on Ectoparasites of Small Mammals in the Brazilian Atlantic Forest

Abstract

Habitat reduction is one of the greatest threats to biodiversity and one of its many expected consequences is the negative impacts on host species. In this study, we evaluated if the reduction in the forest cover positively affected the richness and abundance of ectoparasites and rates of parasitism on mammal species. The study was carried out in the Atlantic Forest biome in the state of Bahia between January to March and September to November of 2011. We sampled four areas with different amounts of forest cover (%) in the municipalities of Valença (25%), Nilo Peçanha (35%), Camamú (45%) and Jaguaripe (55%). We identified twenty species of ectoparasites (fleas, mites, ticks) on 130 small mammals from 18 species (14 rodents and four marsupials), and the most abundant ectoparasites were mites. We confirmed our main hypothesis: the greater richness and abundance of ectoparasites was associated with a reduction in forest cover, with possible epidemiological implications. The prevalence of ectoparasitism per area varied from 91% in Valença to 50% in Jaguaripe. The mean intensity of ectoparasites per host was 6.5 for Valença, 6.4 for Nilo Peçanha, 10.4 for Camamú and 3.2 for Jaguaripe. Ours findings confirm that the reduction in the amount of forested is related to amplified rates of parasitism and changes in ectoparasites abundance and species richness.

Effects of Season, Habitat, and Host Characteristics on Ectoparasites of Wild Rodents in a Mosaic Rural Landscape

“…In terms of vegetation characteristics, we considered only the presence of woody vegetation, whose effect, when significant, was positive on arachnid prevalence (Table 1) and abundance (Table 2) in M. arvalis and overall. Thus, concerning the effect of woody vegetation, we did not confirm the patterns usually reported in studies such as those in neotropical landscapes, where the reduction in forest cover through deforestation leads to increased rates of parasitism [14,61], probably involving the parasite dilution effect given the higher rodent diversity in natural forests compared with the impoverished rodent communities in habitats affected by deforestation. However, in our landscape, forests were rather species-poor, most often with only one captured species per habitat, while the greatest richness was found in fallows and field margins [18], both being habitats without woody vegetation.…”

Recovery of small rodents from open‐pit marble mining: effects on communities, populations, and individuals

“…This suggests that an alternative co‐factor may be driving successional changes among small rodents, where the advantages of denser vegetation may only become influential once the relative benefits for rodents shift to concealing themselves from predators, rather than exposing themselves to ectoparasites (Santos et al. 2018).…”

“…Although increasing vegetation and annual seed production 10 years after mine abandonment could account for the mid-successional increase in rodent populations, we observed that vegetation layer coverage had no significant effects on the abundance, sex ratio, and relative population density of small rodents at the community and population levels. This suggests that an alternative co-factor may be driving successional changes among small rodents, where the advantages of denser vegetation may only become influential once the relative benefits for rodents shift to concealing themselves from predators, rather than exposing themselves to ectoparasites (Santos et al 2018).…”