Fragmented forest affects the southern black-horned capuchin (Sapajus nigritus cucullatus) in the Argentinean Atlantic Forest

Abstract

The southern black-horned capuchin, Sapajus nigritus cucullatus, is considered Near Threatened on the IUCN Red List andVulnerable in Argentina. The species is mainly threatened by habitat loss and fragmentation. The aim of this study was tocompare range size, group size, and density in S. n. cucullatus groups between areas of continuous and fragmented habitatin the Atlantic Forest in Argentina. The study was carried out in two areas in northern Misiones province, one continuousand one anthropogenic fragment. Fieldwork was carried out for 5 days each month from November 2019 to March 2020 andfrom November 2020 to March 2021. SARS-CoV-2 restrictions meant we could not survey in the intervening period. Groupcounts were made on existing trails and subsequent group follows. We georeferenced encounters and follows to estimatehome range sizes. We calculated density based on home range modeling using 100% minimum convex polygons (MCP), andcompared these using generalized linear models (GLM). Smaller groups and lower density of S. n. cucullatus were foundin continuous forest, with group sizes between 12 and 23 individuals, and density of 0.14 ind/ha, whereas in the fragmentedforest, group sizes were between 32 and 36, with density of 0.62 ind/ha (n = 107; zero-inflated negative binomial regression[ZINB], p < 0.05). The higher density in forest fragments may be due to reduced dispersal ability. This work highlights dataon species plasticity that could contribute to the development of conservation management strategies for S. n. cucullatusand its habitat.