Dic 142011

Modeling of Geographic Distributions

Phase I represents a fundamental stage for the project, given that its ouput will be used to define all recommendations relating to the design of field studies for each Pyrrhura population. Our methodology is based on using niche models in combination with past and present climatic information to identify biogeographic patterns for Pyrrhura parakeets in Colombia.

Below is a summary of the most important results obtained to date and more detailed information will be available soon in scientific publications that can be requested from the project team.

  • Preliminary distribution models of Painted Parakeet Pyrrhura picta populations in Colombia were disseminated and discussed at the III Colombian Zoology Congress. As expected, models suggested that under a prediction based on bioclimatic parameters, the subspecies subandina and caeruleiceps (including pantchkenkoi) are completely isolated.
  • We detected patterns in the climatic niches of Andean and trans-Andean species of Pyrrhura, such that their presence was strongly associated with humid regions with limited seasonanality in temperature and precipitation.
  • Similar to other proposed distributions, our climatic niche-based models confirmed that the Andean and trans-Andean populations are allopatric, and have restricted and fragmented geographic ranges.
 This map details the previous and commonly accepted distribution for Pyrrhura species in Colombia. After analyzing the obtained distribution models, we confirmed that populations have an allopatric distribution. Image: SELVA Archive.
  • Based on estimates of extent of occurrence and area of occupancy and on the IUCN’s criteria B1 and B2, we found that all Andean and trans-Andean populations (species or subspecies) should be considered threatened with extinction.
  • Using multiple replicates during modeling and a ‘Simpatry probability index’, we concluded that subspecies of Maroon-tailed Parakeet P. melanura and Painted Parakeet P. picta are geographically isolated and should be considered as independent conservation units.
  • Estimates derived from a Gap Analysis confirmed that Flame-winged Parakeet P. calliptera is vulnerable (VU), when considering criteria B1 and B2 alone.
  • Gap analyses suggest that Andean and trans-Andean races of P. melanura and P. picta should be considered as target populations for local and national conservation policies.
  • Given their loss of a high perecentage of original habiat cover, their restricted area of occupancy and their sensitivity to forest fragmentation, urgent actions are highly recommended for of P. p. caeruleiceps and P. p. subandina populations.
Pyrrhura melanura chapmani is one of the geographically isolated races of Pyrrhura melanura. It has a restricted range associated with humid zones in the upper Magdalena Valley, and its habitat is being degraded and fragmented due to agriculture. Image: SELVA Archive.