Search

Habitat loss, fragmentation, and degradation of habitats are among the most pervasive impacts on species persistence. Mammals may vary in their response to these impacts, both in abundance and in physiological parameters. Herein, we verified how habitat quality influenced the small mammal nutritional status and stress levels among five semi‐deciduous forest remnants in the Brazilian Cerrado. To assess species' physiological responses, we used body condition as an indicator of nutritional status and neutrophil/lymphocyte (N/L) ratio as an indicator of chronic stress in Gracilinanus agilis and Rhipidomys macrurus. We sampled 264 animals belonging to the following species: G. agilis, Didelphis albiventris, Akodon montensis, Oligoryzomys spp., Rattus rattus, R. macrurus, Oecomys cleberi, Hylaeamys megacephalus, and three unidentified rodent species. We found no negative effect of reduced habitat quality on the body condition of G. agilis and R. macrurus, however, the N/L ratios of these species were lower only in high‐quality habitats, demonstrating that this parameter is an accurate indicator of chronic stress. Based on preliminary analysis, we also reported an impoverished fauna, mainly dominated by generalist species, in low‐quality habitats. Thus, we conclude that short‐term reduction in habitat quality leads to increased stress levels, which can in turn lead to future population declines and culminate in biotic homogenization. [ABSTRACT FROM AUTHOR]

The aggregation of parasites among hosts is associated with differential host exposure and susceptibility to parasites, which varies according to host gender, body size, reproductive status and environmental factors. We evaluated the role of these factors on infestation by Eimeria spp. (Eimeriidae) in the agile gracile mouse opossum (Gracilinanus agilis), a semelparous didelphid inhabiting neotropical savannahs. Eimeria spp. abundance and prevalence among G. agilis were associated with the breeding status of individuals and to a lesser extent to climatic season, with both sexes presenting higher Eimeria spp. burdens during late breeding/wet season. On the other hand, male-biased parasitism was restricted to dry/mating season. We suggest that male spatial organization and diet may account for increased parasite burdens within this sex, although future studies should evaluate the role of physiological differences associated with androgen hormones. Finally, a rapid increase in Eimeria spp. loads among females during the late breeding/wet season seems associated with seasonal changes in susceptibility, due to breeding costs related to semelparity, and exposure to infective propagules, while male-die off seems to explain maintenance of higher Eimeria spp. burdens within this sex in the same period. [ABSTRACT FROM AUTHOR]