Fig 1.
Geographic distribution of Acorn Woodpecker (Melanerpes formicivorus).
An expert range map of Acorn Woodpecker from BirdLife International is shown in light blue. Inset shows a male Acorn Woodpecker (photograph by Walt Koenig). Reprinted under a CC BY license, with permission from Walt Koenig, original copyright 2011.
Fig 2.
Species distribution models generated for Acorn Woodpecker in northern Andes.
Habitat suitability is shown as a continuous variable, in which green colors indicate highly suitable habitat, with (A) abiotic variables alone, (B) Quercus presence alone, and (C) abiotic variables + Quercus presence. We converted continuous measures of habitat suitability into binary presence and absence models by setting the threshold to the value that maximizes the parameter Kappa, which is an index of model performance. Binary conversions were done for (C) abiotic variables alone and (D) abiotic variables in addition to presence of Quercus. Excluding Quercus occurrence points generated species distribution models that over-predict the occurrence of Acorn Woodpeckers in South America.
Table 1.
Relative contributions of variables in “abiotic only” species distribution model for Acorn Woodpeckers (Melanerpes formicivorus).
Table 2.
Relative contributions of abiotic and biotic variables in the “abiotic and Quercus” species distribution model for Acorn Woodpeckers (Melanerpes formicivorus).
Fig 3.
Performance indices of species distribution models constructed from only abotic climatic variables (red), only Quercus occurrence data (yellow), and abiotic climatic variables plus Quercus occurrence data (blue).
Species distribution models that include Quercus occurrence data consistently perform better than models constructed from abiotic variables alone based on (A) AUC scores; (B) area under the curve of Kappa values; (C) overall performance sensu Anderson et al. [47]; (D) commission (false positive) indices; and (E) omission (false negative) indices. Note that the Pearson’s correlation coefficient is not included in this figure because it does not lend itself to visualization.
Table 3.
Performance indices of species distribution models of Acorn Woodpeckers.