Population Viability Analysis of the Blue-Throated Macaw (Ara glaucogu-laris) Using Individual-Based and Cohort-Based PVA Programs

Abstract

We developed a demographic model to perform a population viability analysis (PVA) of the Blue-throated Ma- caw (Ara glaucogularis), a critically endangered species endemic to Bolivia. PVA simulations were run using individual- based (VORTEX 9.72) and cohort-based (RAMAS GIS 4.0) programs. A baseline simulation allowed for the assessment of the status of the species based on estimates of extinction risk and population declines under current conditions of abun- dance and habitat availability. The role of multiple demographic, environmental, and anthropogenic parameters was evaluated to assess changes affecting population declines and extinction risk. The baseline simulation showed that the Blue-throated Macaw has a relatively low probability of extinction during the next fifty years. However, continuing threats, including declines in abundance, small population size, and low population growth rates, make this species highly vulnerable to any change. Elasticity analysis of the baseline simulation and sensitivity analysis of changes in different demographic parameters demonstrated that increases in adult mortality had the greatest effect on population growth rate and extinction risk. Furthermore, simulations of anthropogenic impacts showed that small increases in habitat loss (2%) and population harvesting (3%) had drastic effects on population decline. Results from this study emphasize the need for conservation actions aimed at protecting breeding individuals (i.e., decreasing adult mortality), preventing poaching ac- tivities, and promoting the conservation of available habitat for nesting sites.