Species distribution modeling and conservation assessment of the black-headed night monkey (Aotus nigriceps): A species of least concern that faces widespread anthropogenic threats

Deforestation rates in the Brazilian Amazon have been steadily increasing since 2007. Due to recent government policy, the projected growth of agriculture and expansion of the cattle industry is expected to further strain biodiversity across the region, with many wide-ranging primate species within these areas facing declines as a result. In this study, we examined the anthropogenic impact on the widely distributed black-headed night monkey, Aotus nigriceps, which is listed as least concern but whose distribution and population trends has yet to be assessed. In this study, we 1) modeled species distribution in A. nigriceps; 2) estimated impact of habitat loss and degradation on population trends; and 3) highlight landscape-based conservation actions which maximize potential for their long-term sustainability in the region. We found the black-headed night monkey to be restricted by biotic and environmental factors such as high elevation, low temperature range, low isothermality and high forest cover. Over the last two decades, over 132,908 km2 of tree cover (18.3 %) within their documented range has been lost. We found only 40.4 % of suitable habitat in their range, a loss of 17.1 % of their estimated distribution in 2000, and just over 22.3 % of suitable habitat was in protected areas. Projected deforestation rates across present-day modeled distribution of A. nigriceps equates to an additional loss of 37,295 km2 of habitat over the next decade. This study demonstrates how this species of least concern has a much more reduced range and is likely more at risk than previously described. The future impact of continued expansion of mono-cultured crops, cattle ranching, and wildfires is still unknown. However, expanded use of participatory and jurisdictional REDD+, sustainable agroforestry in buffer zones, secured land tenor for indigenous communities, maintenance of wildlife corridors, and the expansion and strengthening of protected areas can help ensure viability and reduce risk of widespread loss for this and other species throughout the Amazon Basin.