Modelling the range of Syrian spadefoot toad (Pelobates syriacus) with combination of GIS-based approaches

Tarkhnishvili, David and Serbinova, Irina and Gavashelishvili, Alexander (2009) Modelling the range of Syrian spadefoot toad (Pelobates syriacus) with combination of GIS-based approaches. Amphibia-Reptilia, 30 (3). pp. 401-412. ISSN 1568-5381

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Syrian spadefoot toads (Pelobates syriacus) are found from Balkan Peninsula throughout the Caucasus, Middle East, and Northern Iran. However, the range of this species is sufficiently mapped only in Balkans. Based on the detailed mapping of the species in Georgia, we analysed the environmental factors influencing species occurrence and produced spatial models for the entire range. Nine models based on the logistic regression, discriminant function analysis, and classification tree analysis, all showed significant influence of the vegetation index and maximum summer temperature on the species distribution. The habitat suitability models based on the presence-only data (Mahalanobis distance estimation and Maximum Entropy approach) had a better performance than the models based on the presence-absence data. The habitat suitability models included two variables only, identified as significant in all preliminary analyses. The area identified as suitable by presence-only models strongly increases when a few environmental variables are included in the analysis. When only two variables are considered, the model predicted large areas north of the actual range. Competition with the related common spadefoot toad (P. fuscus) might have a role on the position of the northern limit of the range of P. syriacus. Within the predicted range, use of breeding sites is negatively associated with presence of fish. Breeding pond preferences of P. syriacus were particularly similar to those of the lake frog (Rana ridibunda), although the latter species uses appropriate habitats more extensively.

Item Type: Article
Subjects: Q Science > Conservation Biology
Q Science > Ecology
Q Science > QL Zoology
Divisions: Institutes > Institute of Ecology
Depositing User: Prof. David Tarkhnishvili
Date Deposited: 30 Jan 2014 13:04
Last Modified: 30 Jan 2014 13:04

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