Modelling the potential winter distribution of the endangered Black-capped Vireo (Vireo atricapilla)

• Published in: Bird conservation international 2011-03, Vol.21 (1), p.92-106
• Main Authors: VEGA RIVERA, JORGE H., ORTEGA-HUERTA, MIGUEL A., SARKAR, SAHOTRA, RAPPOLE, JOHN H.
• Format: Article
• Language: English
• Subjects: Dry forests; Land use; Protected areas; Tropical forests
• ISSN: 0959-2709; 1474-0001
• DOI: 10.1017/S0959270910000365

We applied the ecological niche/habitat modelling approach to predict the potential winter distribution of the endangered Black-capped Vireo Vireo atricapilla. We used historical and current field records along with climatic and topographic variables to generate three different models (Biomapper, Maxent, and GARP). Using field data on species occurrence, a model was selected based on the accuracy of assessment results. A final model was obtained by eliminating those areas mapped as known unsuitable habitat, using high resolution land use/land cover data. The GARP model obtained the best accuracy values. It showed the winter distribution of the Black-capped Vireo to cover an area in western Mexico of about 141,000 km2 that runs along the Pacific coast from southern Sonora (Río Yaqui, Alvaro Obregón Dam) to the southern state of Oaxaca (Salina Cruz on the Pacific coast and Matias Romero, and inland). One third of the proposed model’s area was located at elevations of 0–500 m, while 83% occurred at elevations < 1,250 m; however, a significant area (17%) consists of sites > 1,250 m in elevation. For the most part, the distribution model proposed closely followed the tropical dry forest boundaries and clearly avoided temperate areas at higher elevations. This situation seems to be critical for the species, since the dry forest is one of most endangered Neotropical ecosystems, both nationally and internationally. Furthermore, the array of areas under protection regimes included only about 7.1% of the predicted wintering area. However, this figure could be misleading when it is considered that some protected areas are just “paper reserves” without significant conservation programmes developed in situ. En este estudio aplicamos los conceptos de nicho ecológico/modelado del hábitat para predecir la distribución invernal del Vireo atricapilla, una especie amenazada. Para esto, utilizamos registros de campo históricos y actuales, en combinación con variables climáticas y topográficas para generar tres modelos diferentes (Biomapper, Maxent, y GARP), de los cuales seleccionamos el mejor modelo mediante un análisis de precisión. El modelo final se obtuvo después de eliminar aquellas áreas con hábitat no adecuado para la especie, utilizando mapas de vegetación de alta resolución. El modelo GARP obtuvo los valores más altos de precisión. Este modelo muestra que la distribución potencial del Vireo atricapilla cubre un área en el oeste de México de 141,000 km2, a lo largo d