BackgroundCurrently, many species are facing serious conservation problems due to habitat loss. The impact of the potential loss of biodiversity associated with habitat loss is difficult to measure. This is particularly the case with inconspicuous species such as the threatened pudú (Pudu puda), an endemic Cervidae of temperate forests of Chile and Argentina. To evaluate the effectiveness of the Chilean protected-area system in protecting the habitat of the pudú, we measured the congruence between this specie’s potential distribution and the geographical area occupied by the protected areas in central and southern Chile. The measurements of congruency were made using the Maxent modeling method.ResultsThe potential habitat of the pudú was found to be poorly represented in the system (3–8 %) and even the most suitable areas for the species are not currenly protected. According to these results, the protected area network cannot be considered as a key component of the conservation strategy for this species.ConclusionsThe results presented here also serve as a guide for the reevaluation of current pudú conservation strategies, for the design of new field studies to detect the presence of this species in human-disturbed areas or remaining patches of native forest, and for the implementation of corridors to maximize the success of conservation efforts.Electronic supplementary materialThe online version of this article (doi:10.1186/s12898-015-0055-7) contains supplementary material, which is available to authorized users.

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Aging results in declines in immune function and increases in inflammation, which underlie many age-related diseases. These immunosenescent signatures are similar to those seen in individuals exposed to social adversity, who may age more rapidly than those unexposed. Yet, it is unclear how social adversity alters immunity across demographic factors - data that are essential to identify how it might increase aging-related diseases. Here, we investigated how age, sex, and social adversity predicted immune cell proportions in 250 rhesus macaques living in a semi-naturalistic colony. As macaques aged, they exhibited signatures of immunosenescence. Older individuals had signatures of diminished antibody production and adaptive immunity, with declines in CD20+ B cells, CD20+/CD3+ cell ratio, and the CD4+/CD8+ T cell ratio. At all ages, females had higher CD20+/CD3+ and CD4+/CD8+ ratios, indicative of a stronger antibody and adaptive immune response that may facilitate pathogen clearance even with increasing age. Older individuals had signatures of inflammation, with higher proportions of CD3+/CD8+ Cytotoxic T cells, CD16+/CD3- Natural Killer cells, CD3+/CD4+/CD25+ and CD3+/CD8+/CD25+ T regulatory cells, and CD14+/CD16+/HLA-DR+ intermediate monocytes, combined with lower levels of CD14+/CD16-/HLA-DR+ classical monocytes. Notably, we found an interaction between age and social adversity, where low-status individuals had higher proportions of CD3+/CD4+/CD25+ T regulatory cells for their age, compared to higher-status individuals. Together, our study identifies immune cell types that are affected by age and sex in the premier nonhuman primate model of human biology and behavior, and demonstrate a novel link between inflammatory CD4+ T regulatory cells and social adversity.

Affiliative social relationships and high social status predict longer lifespans in many mammal species, including humans. Yet, the mechanisms by which these components of sociality influence survival are still largely unknown. Using 10 years of long-term data on the incidence of injuries in a free-ranging population of rhesus macaques (Macaca mulatta), we investigated two possible mechanisms that could underpin the relationship between sociality and survival: sociality (1) reduces injury risk; and/or (2) increases the probability of survival after an injury. Our results showed that injured animals had a near three-fold increase in the probability of dying, confirming that injuries can be fatal in this population. Crucially, we found that sociality may reduce an individual's injury risk, but had no effect on the probability of injured individuals dying. Individuals with more affiliative partners and higher social status experienced fewer injuries compared to less socially integrated or lower status animals, with the effect of social status varying with age. Females living in bigger groups were more likely to be injured than those in smaller groups, while in males, smaller groups were associated with higher chances of being injured. Our study contributes novel evidence that sociality does not provide fitness benefits via socially-mediated promotion of injury recovery, but instead can enhance fitness by reducing the risk of being fatally injured in the first place.