Population Density Estimates of Night Monkeys (Aotus azarae boliviensis) in Tambopata, Peru
Abstract
Habitat loss is a major problem for many forest dwelling species worldwide. This habitat loss is often due to activities associated to population growth, and nonhuman primates are among the most affected by these forest changes in tropical regions. Azara’s night monkey (Aotus azarae boliviensis) is experiencing threats such as commercial gold mining, infrastructure development, deforestation for agriculture, and subsistent hunting and trade in the northernmost distribution of their range in Tambopata, Peru. Whereas the IUCN Red List currently classifies this species as “Least Concern”, continued high rates of habitat loss suggests that additional data may be needed to reevaluate this subspecies’ conservation status. This paper provides population density estimates of A. a. boliviensis at three distinct forest sites experiencing varying degrees of disturbance (i.e. new secondary, old secondary, primary). This was done by walking transects along the existing trail systems at each site in order to detect and count population numbers of A. a. boliviensis. Vegetation was also sampled at each site using vegetation plots. For each plot, relevant forest characteristics were recorded. Over the course of 120.54 kilometers and 78 hours of surveying, I detected 24 monkeys at the new secondary forest site, 22 monkeys at the old secondary forest site, and 11 monkeys at the primary forest site, for a total of 57 monkeys across all sites. We calculated population densities of 25.1 monkeys/km² at the new secondary forest site, 30.5 monkeys/km² at the old secondary forest site, and 15.0 monkeys/km² at the primary forest site, though there was not a significant difference between these values at each site. There was also no significant difference between the forest measurements at each site, which could be attributed to the sites’ uses for ecotourism. Based on these results, it may be true that A. a. boliviensis prefers slightly disturbed secondary forest sites. Population densities in this study are lower than most other estimates, especially of the same species in a similar area. Consequently, the IUCN red list classification for this species should incorporate the extensive variation in density and behavior when reevaluating this species conservation status.
Citation
Pryor, Mackenzie Rose (2020). Population Density Estimates of Night Monkeys (Aotus azarae boliviensis) in Tambopata, Peru. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /191826.