Abstract
Assessments of the status of endangered species have focused on population sizes, often without knowledge of demographic and behavioral processes underlying population recovery. We analyzed demographic data from a 28-year study of a critically endangered primate, the northern muriqui, to investigate possible changes in demographic rates as this population recovered from near extirpation. As the population increased from 60 to nearly 300 individuals, its growth rate declined due to increased mortality and male-biased birth sex ratios; the increased mortality was not uniform across ages and sexes, and there has been a recent increase in mortality of prime-aged males. If not for a concurrent increase in fertility rates, the population would have stabilized at 200 individuals instead of continuing to grow. The unexpected increase in fertility rates and in adult male mortality can be attributed to the muriquis’ expansion of their habitat by spending more time on the ground. The demographic consequences of this behavioral shift must be incorporated into management tactics for this population and emphasize the importance of understanding demographic rates in the recovery of endangered species.
Highlights
With nearly half of the world’s primates threatened with extinction, the need for accurate assessments of remaining populations is more urgent than ever [1,2]
We investigate the demographics of one population of the critically endangered northern muriqui using data from a 28-year field study initiated in 1983 at the Reserva Particular do Patrimonio Natural Feliciano Miguel Abdala, a 957 ha forest in Minas Gerais, Brazil (19u50’S, 41u509W)
Our Generalized Linear Mixed Models (GLMMs) differ from those in Morris and colleagues [20] in that (i) we use finer age classes; (ii) we analyze survivorships for all age classes simultaneously; and (iii) we allow vital rates to change through time
Summary
With nearly half of the world’s primates threatened with extinction, the need for accurate assessments of remaining populations is more urgent than ever [1,2]. Small primate populations may grow when they and their habitats are well protected, whether these populations can persist over the long-term is not yet known [8,9,10]. This uncertainty is especially problematic for forest-dwelling primates with minimal or no dispersal opportunities as a result of habitat fragmentation. In such isolated refuges, population growth may create demographic stresses, making it difficult to distinguish healthy, recovering populations from those that are vulnerable or require active management [11,12]. Mendes and in compliance with all Brazilian and U.S regulations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
