Gherghel_et_al_Podarcis_muralis

Podarcis muralis distribution records used and discussed in the paper. The records are in shapefile format

Refining Climate Change Projections for Organisms with Low Dispersal Abilities: A Case Study of the Caspian Whip Snake

<div><p>Climate warming is one of the most important threats to biodiversity. Ectothermic organisms such as amphibians and reptiles are especially vulnerable as climatic conditions affect them directly. Ecological niche models (ENMs) are increasingly popular in ecological studies, but several drawbacks exist, including the limited ability to account for the dispersal potential of the species. In this study, we use ENMs to explore the impact of global climate change on the Caspian whip snake (<i>Dolichophis caspius</i>) as model for organisms with low dispersal abilities and to quantify dispersal to novel areas using GIS techniques. Models generated using Maxent 3.3.3 k and GARP for current distribution were projected on future climatic scenarios. A cost-distance analysis was run in ArcGIS 10 using geomorphological features, ecological conditions, and human footprint as “costs” to dispersal of the species to obtain a Maximum Dispersal Range (MDR) estimate. All models developed were statistically significant (<i>P</i><0.05) and recovered the currently known distribution of <i>D. caspius</i>. Models projected on future climatic conditions using Maxent predicted a doubling of suitable climatic area, while GARP predicted a more conservative expansion. Both models agreed on an expansion of suitable area northwards, with minor decreases at the southern distribution limit. The MDR area calculated using the Maxent model represented a third of the total area of the projected model. The MDR based on GARP models recovered only about 20% of the total area of the projected model. Thus, incorporating measures of species’ dispersal abilities greatly reduced estimated area of potential future distributions.</p></div

Percent of suitable niche overlap between the two emission scenarios (A2a and B2a) for the studied time periods (2020, 2050, 2080).

<p>Percent of suitable niche overlap between the two emission scenarios (A2a and B2a) for the studied time periods (2020, 2050, 2080).</p

Percent of the area predicted accessible for <i>D. caspius</i> of the total projected space in the context of global warming based on two climate change emission scenarios (A2a and B2a) and the three scenarios of Maximum Dispersal Range (MDR).

<p>Percent of the area predicted accessible for <i>D. caspius</i> of the total projected space in the context of global warming based on two climate change emission scenarios (A2a and B2a) and the three scenarios of Maximum Dispersal Range (MDR).</p

Variable selection results indicating percent contributions to the initial and last models.

<p>*variables eliminated due to low contribution to model development.</p

Future climatically suitable ranges for the Caspian whip snake, <i>Dolichophis caspius</i>.

<p>Future climatically suitable ranges for the Caspian whip snake, <i>Dolichophis caspius</i>.</p

Maximum dispersal range estimates (blue) using Maxent and GARP future potential distributions (A2a – liberal scenario and B2a – conservative scenario) and three dispersal scenarios (S1 - permissive scenario, S2 - restrictive scenario, S3 - balanced scenario).

<p>The known species’ range is shown in red dotted line.</p

Percent of climatically suitable areas available for the Caspian whip snake of the total projected space.

<p>Percent of climatically suitable areas available for the Caspian whip snake of the total projected space.</p