Environmental Factors Influencing the Distribution of Bats (Chiroptera) in South Africa
Author | : Hassan Aburaida Babiker Salata |
Publisher | : |
Total Pages | : 0 |
Release | : 2012 |
Genre | : Bats |
ISBN | : |
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Environmental factors limiting the distribution of 37 of the 56 bat species in a warm temperate region (South Africa) were determined using GIS software and the Maximum Entropy modelling technique (MaxEnt). Undertaking such a study in a warm temperate region like South Africa is essential as the outcomes of this study could inform our general understanding of distributions of other animals in other parts of the world. Hypotheses related to the ecological niche-based characteristics of species were tested to identify the most important variables influencing the distribution of South African bats and to predict the probability of occurrence for bat species in South Africa. A database that included locality records for bat species from different museums in South Africa was compiled and then combined with the researcher's own data for the Northern Cape Province as there was insufficient knowledge of bat distributions in this province. A total of 23 environmental variables were considered, of which 20 were downloaded from the WorldClim database as potential environmental variables influencing the contemporary distribution of bats in South Africa based on previous studies that use environmental variables from WorldClim to predict the distribution of species. The environmental variables were grouped into broad categories, temperature, precipitation, and biophysical (i.e., vegetation biomes, land use/land cover, geology) variables. As predicted, taxonomic affiliations appear to have no bearing on which factors influenced the geographic distribution of South African bat species. The distributional limits of even closely related species within the same genus appear to be influenced by disparate environmental factors. Geology appeared to be the most important limiting factor for 15 of the 37 species, all of which are known to use roosts associated with geological features (i.e., caves, mines and rock crevices). Land use/land cover influenced the distribution of six bat species.