A primate at risk in Northeast Brazil: local extinctions of Coimbra Filho's titi (Callicebus coimbrai).

Identifying the factors that determine local extinction of populations is crucial to ensure species conservation. Forest-dwelling primates are especially vulnerable to habitat fragmentation, although few studies have provided systematic evidence of local extinctions. Over an 11-year period, approximately 100 remnant populations of the endangered Coimbra Filho's titi monkey (Callicebus coimbrai) have been found within the geographic range of the species in Bahia and Sergipe, Northeast Brazil. During the present study, extinction of 13 of these populations was recorded through intensive surveys. These extinctions were detected from evidence of intensive logging and clear-cutting, interviews with local residents and systematic searches of the sites where occurrence of the species had been confirmed in previous surveys. These local extinctions represent approximately 10 % of the known populations of C. coimbrai and up to 28.3 % of the area occupied by the species. Comparison of the vegetation structure in fragments where extinction was recorded and where the species still occurs indicated that sparser understorey may be a correlate of extinction, combined with the fact that extinctions occurred within fragments characterised by relatively high levels of anthropogenic disturbance. These findings reinforce the Endangered status of the species and the urgent need for intensification of conservation measures within the most impacted areas of the geographic distribution of C. coimbrai.