Fitzgerald, Maegan Annette (2017-08). Modeling Habitat Suitability for Pan troglodytes verus in Montane Rainforests. Master's Thesis. Thesis uri icon

abstract

  • Tropical forests and the biodiversity within them are rapidly declining in the face of an increasing human population. Resource management and conservation of endangered species requires an understanding of how species perceive and respond to their environment so efforts can focus on areas of high importance for the species of concern. Species Distribution Modeling (SDM) is an appropriate tool for identifying conservation areas of concern and importance. In this study, maximum entropy SDM was used to identify areas of suitable chimpanzee (Pan troglodytes verus) habitat within the Greater Nimba Landscape of Guinea, Africa. This is an ideal location to study the effects of landscape structure on habitat suitability due to the topographic variation of the landscape and the Critically Endangered status of the chimpanzee communities in this area. Suitable habitat was predicted based on the location of direct and indirect signs of chimpanzee presence and the spatial distribution of 12 biophysical variables within the study area. Model performance was assessed by examining the area under the curve (AUC) for the test data. The overall predictive performance of the model was 0.721 (random expectation results in AUC = 0.5). Models with AUC values greater than 0.70 are considered to have fair discriminative abilities and are ecologically useful. In addition to a map showing suitable chimpanzee habitat, the model identified the biophysical variables contributing most to habitat suitability (permutation importance). The variables most influencing habitat suitability for chimpanzees in the study area were normalized the difference vegetation index (37.8%) elevation (27.3%), hierarchical slope position (11.5%), brightness (6.6%), and distance to rivers (5.4%). Moreover, the final model highlighted the isolation and fragmentation of chimpanzee habitat within the Greater Nimba Landscape. Understanding the factors influencing chimpanzee habitat suitability, specifically the biophysical variables considered in this study, will greatly contribute to efforts to conserve Endangered chimpanzees.
  • Tropical forests and the biodiversity within them are rapidly declining in the face of an increasing human population. Resource management and conservation of endangered species requires an understanding of how species perceive and respond to their environment so efforts can focus on areas of high importance for the species of concern. Species Distribution Modeling (SDM) is an appropriate tool for identifying conservation areas of concern and importance. In this study, maximum entropy SDM was used to identify areas of suitable chimpanzee (Pan troglodytes verus) habitat within the Greater Nimba Landscape of Guinea, Africa. This is an ideal location to study the effects of landscape structure on habitat suitability due to the topographic variation of the landscape and the Critically Endangered status of the chimpanzee communities in this area. Suitable habitat was predicted based on the location of direct and indirect signs of chimpanzee presence and the spatial distribution of 12 biophysical variables within the study area. Model performance was assessed by examining the area under the curve (AUC) for the test data.

    The overall predictive performance of the model was 0.721 (random expectation results in AUC = 0.5). Models with AUC values greater than 0.70 are considered to have fair discriminative abilities and are ecologically useful. In addition to a map showing suitable chimpanzee habitat, the model identified the biophysical variables contributing most to habitat suitability (permutation importance). The variables most influencing habitat suitability for chimpanzees in the study area were normalized the difference vegetation index (37.8%) elevation (27.3%), hierarchical slope position (11.5%), brightness (6.6%), and distance to rivers (5.4%). Moreover, the final model highlighted the isolation and fragmentation of chimpanzee habitat within the Greater Nimba Landscape. Understanding the factors influencing chimpanzee habitat suitability, specifically the biophysical variables considered in this study, will greatly contribute to efforts to conserve Endangered chimpanzees.

publication date

  • August 2017