Long‐term population monitoring of the threatened and endemic black‐headed squirrel monkey (Saimiri vanzolinii) shows the importance of protected areas for primate conservation in Amazonia

• Published in: American journal of primatology Vol. 81; no. 6; pp. e22988 - n/a
• Main Authors: Paim, Fernanda P., El Bizri, Hani R., Paglia, Adriano P., Queiroz, Helder L.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-07-2019
• Subjects: Animals; Annual variations; Brazil; Cebidae; Climate change; Conservation; Conservation of Natural Resources - methods; Conservation of Natural Resources - statistics & numerical data; Conservation status; Counting; distance sampling; encounter rate; Endangered; Endangered Species; Endemism; flooded forests; Floods; Forests; Monitoring; Monkeys; Population; Population Density; Population number; Primates; Protected areas; Protected species; Recording; Rivers; Saimiri; Saimiri vanzolinii; Sampling; Social Behavior; Squirrels; Sustainable development; Threatened species; Water; Wildlife conservation; Brazil; distance sampling; flooded forests; encounter rate; Cebidae; threatened species
• ISSN: 0275-2565; 1098-2345
• DOI: 10.1002/ajp.22988

Population monitoring of endangered species is essential to the improvement of their management and conservation plans. The black‐headed squirrel monkey (Saimiri vanzolinii) is a vulnerable species on the IUCN Red List and has extreme geographical endemism, exhibiting the smallest known distribution among Neotropical primates (ca. 870 km2), over 90% of which occurs in white‐water flooded forests within the Mamirauá Sustainable Development Reserve (MSDR), Brazilian Amazonia. To assess the effectiveness of this protected area in conserving the species, we conducted population monitoring of black‐headed squirrel monkeys across five consecutive years (2009–2013) on nine trails 2 km each. Each year samples included both low and high river water periods. We used the distance sampling method, recording the distance to each observed social group as well as counting component individuals. We also calculated annual encounter rates based on the number of individuals sighted every 10 km traveled. Densities ranged from 256 individuals/km2 (2011) to 453 individuals/km2 (2013), and no seasonal differences were detected. Population size was estimated to be 147,848 mature individuals. Encounter rates ranged from 100 individuals/10 km (2010) to 179 individuals/10 km (2013); no significant difference among years was found. We found that S. vanzolinii populations remained stable throughout the years, which indicates that the MSDR has been playing an essential role on protecting this species. Due to difficulties of fulfilling assumptions of the distance sampling method, we consider the encounter rate analysis to be more effective for monitoring this and other Saimiri species. Given the critical endemism and worrying conservation status of S. vanzolinii, we suggest that monitoring of the species population should be carried out regularly.
Saimiri vanzolinii populations remained stable over 5 years, indicating that Mamirauá Reserve has been playing an essential role on its conservation.
HIGHLIGHTS
Saimiri vanzolinii population remained stable over a 5‐year monitoring period in the Mamirauá Reserve, Brazil.
Given the species' extreme endemism and the threats posed by climate change, this population should be monitored at regular intervals of 5 years.