Distribución geográfica y ecológica, tamaño poblacional y vacíos de conservación del periquito de Santa Marta (Pyrrhura viridicata)

Geographical and ecological distribution, population size, and conservation gaps of the Santa Marta Parakeet (Pyrrhura viridicata)

Abstract

The Santa Marta Parakeet (Pyrrhura viridicata) is an endemic and threatened species from Colombia, whose conservation needs include determining its population status and geographical distribution. This study compiled and analyzed geographic and population data obtained between 2006 and 2012 to aid the establishment of the species' current status. We modeled the species' potential distribution using the MaxEnt algorithm, and we estimated the area of occupancy and remaining habitat using a geographic information system. We combined these results to identify conservation gaps. Extrapolating from population density values obtained on the San Lorenzo slope in 2006 and 2008, we estimated the species’ population size based on its area of occupancy and the extent of remaining habitat. The distribution model revealed that P. viridicata is restricted to humid forests mainly between 2000-3000 m elevation on the northern flank of the Sierra Nevada de Santa Marta, in areas where seasonality in precipitation and in temperature is low. Assuming total occupation of remaining habitat (680 km2) and similar population densities across the species range, we estimate a population size of 2900-4800 individuals. If occupation is only partial, then the population is not expected to exceed 2500 individuals. A gap analysis indicated that 80% of the species’ predicted range lies within protected areas, but we recommend increasing coverage through the creation of reserves while simultaneously increasing the efficacy of protective measures in existing protected areas. According to the gap analysis, it is likely that populations in the Ranchería River Basin are isolated from other populations in the massif, because any local migration would require flights through extensively deforested areas or across areas outside of the species' levational range. Validation of the model will help identify other areas of potential occurrence for the species. Population monitoring and studies of habitat selection, home range and population dynamics, will help confirm our conclusions.