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

Abstract

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 km 2 ), 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 andhigh 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/km 2 (2011) to 453 individuals/km 2 (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.

Congruence of local ecological knowledge (LEK)‐based methods and line‐transect surveys in estimating wildlife abundance in tropical forests

“…From the collected data, we calculated the sighting rates (individuals/km, calculated as the total number of individuals observed divided by the total effort in km travelled on any given transect during all seasons), which were used as our abundance index since higher abundance increases species detections (e.g. Paim et al., 2019). The value of zero was assigned to species whose occurrence is confirmed in the area but that were not detected on any transect sampled near that village.…”

The sustainable development goals in two sustainable development reserves in central amazon: achievements and challenges

“…Some of these Amazonian communities already report perceptions of climate change; this fact can influence local farming practices, such as their agricultural calendars are based on hydrological seasons [ 60 ]. Climate change would also threaten mammal species of the Amazon floodplain, such as the Black-headed squirrel monkey ( Saimiri vanzolinii ), an endemic species which whole distribution is within Mamirauá SDR [ 61 ]; this primate will need to adapt to sudden changes in their habitat or migrate to other areas—otherwise could be extinct [ 62 ].…”

“…Eleven primate species from five families live within the boundaries of the Mamirauá SDR [ 62 ]. The black-headed squirrel monkey constitutes an example of extreme endemism, with one of the smallest geographic distributions of all Neotropical primates—around 870 km 2 [ 61 ]; thus, it is listed as Vulnerable on national and international threatened species lists [ 65 , 66 ].…”

Biotic Indicators for Ecological State Change in Amazonian Floodplains

“…Yet others are entirely dependent on flooded forests (e.g., Cacajao calvus calvus , Saimiri vanzolinii : Paim et al. 2019 ) and may respond strongly. Leaf and fruit production timing in flooded and non-flooded adjacent habitats is non-synchronous (Haugaasen and Peres 2005a ; Hawes and Peres 2016 ).…”