**Abstract**

The study of the climate variability in the past and present, correlating those with changes in the distribution range of species, has attracted considerable research interest. The genus *Ablepharus* consists of 10 recognized species, of which *A. bivittatus*, *A. grayanus*, and *A. pannonicus* are documented from Iran. In the present study, we modeled with MaxEnt the potential distribution areas and determined the suitable habitats in the past [mid-Holocene (MH) and the last interglacial (LIG)] and their current distribution for two species of snake-eyed skinks (*A. grayanus* and *A. pannonicus*) separately. Models of the species indicated good fit by the average high area under the curve (AUC) values (*A. grayanus* = 0.929 ± 0.087 and *A. pannonicus* = 0.979 ± 0.007). Precipitation of the driest quarter of the year, mean temperature of the coldest quarter of the year, and precipitation of the driest month variables made important contributions to *A. grayanus*. Two important climate variables contributed importantly to *A. pannonicus*: temperature seasonality and mean temperature of the wettest quarter of the year and one topographic variable, slope. We conclude that these variables form a natural barrier for species dispersal. The MH and the LIG models indicated a larger suitable area than the current distribution.

**Keywords:** climate condition, suitable habitat, potential distribution, mid-Holocene, last interglacial

## **1. Introduction**

Climate change plays an important role on the species distributions of biota. The response of species to persistent climate changes may be as follows: (1) consistently in situ at their tolerance limits, (2) changing ranges to regions where climate is within the species tolerance limits, and (3) extinction [1, 2]. During the Pleistocene, several ice sheets in the Northern Hemisphere occurred at intervals of around 40,000–100,000 years [2]. The glaciations were separated by interglacial periods [3]. During interglacial periods, the climate warmed, and forests returned to areas that once supported tundra vegetation [2]. During the last interglacial period (LIG: 150,000–120,000 years), temperature gradient increased in polar regions toward lower latitudes and caused sea level rise and reduction of ice sheets [4]. Briefly, the climate of the last interglacial had a relatively stable warm period [5]. Kerwin et al. [6] simulated terrestrial conditions at the mid-Holocene (6 ka) that indicated summer temperatures were warmer than at present in the high-latitude Northern Hemisphere. But during the mid-Holocene, northern Africa, Arabia, and southern Asia underwent conditions much wetter than at present, these conditions resulting in both African and Asian monsoons [7, 8].

Analyzing species distribution models can help in conservation planning [9] and in understanding theoretical research [10] on ecological and evolutionary processes [1]. Species distribution models can be used to investigate the effect of climate changes on distributions and abundances of species [11], to determine biodiversity [12] and biogeographical patterns [13], to predict potential distribution [14], and to appraise possible future changes in the diversity [15]. Lizards, like other ectotherms [16], provide excellent models for analysis of species distribution under climate change [2]. MaxEnt is a general approach for characterizing probability distributions from small sample sizes [17–19]. MaxEnt estimates the probability distribution of maximum entropy (i.e., closest to uniform) based on environmental variables spread over the survey area [20, 21].

The Scincidae family has more than 25% of all living genera and species of lizards [22]. The genus *Ablepharus* (Fitzinger, 1823) encompasses 10 valid species: *A. bivittatus* (Menetries, 1832), *A. budaki* (Göcmen, Kumlutas & Tosunoglu, 1996), *A. chernovi* (Darevsky, 1953), *A. darvazi* (Jeremčenko & Panfilov, 1990), *A. deserti* (Strauch, 1868), *A. grayanus* (Stoliczka, 1872), *A. kitaibelii* (Bibron & Bory, 1833), *A. lindbergi* (Wettstein, 1960), *A. pannonicus* (Fitzinger, 1824), and *A. rueppellii* (Gray, 1839) which are distributed in Europe, Turkey, Syria to Egypt, Azerbaijan, Armenia, Caucasus, Tajikistan, Kazakhstan, Kyrgyzstan, Uzbekistan, Turkmenistan, Afghanistan, Iran, Iraq, United Arab Emirates, Pakistan, and NW India [23–28]. The genus *Ablepharus* in the molecular phylogenic aspect is a sister taxon of the central and East Asian *Asymblepharus* [29]. *Ablepharus bivittatus* (Menetries, 1832), *A. grayanus* (Stoliczka, 1872), and *A. pannonicus* (Fitzinger, 1824) occur in Iran [30, 31].

*Ablepharus grayanus* was first described as *Blepharosteres grayanus* from Waggur District, northeast Kutch, India [26]. Later, Fühn [24] regarded it as a subspecies of *A. pannonicus* based on examination of a few specimens (three *A. grayanus*, four *A. pannonicus*). *Ablepharus grayanus* (Stoliczka, 1872) is now regarded as a distinct species. *Ablepharus grayanus* (Stoliczka, 1872) has a distribution range from northern and western India through Pakistan and Afghanistan to Eastern Iran [30, 31]. Researchers based on the morphological characters identified different species and subspecies—*A. brandtii* (Strauch, 1868) from Samarkand, Turkestan; *A. pusillus* (Blanford, 1874) from Basra, Iraq; *A. brandtii* vs. *brevipes* (Nikolsky, 1907) from Dech-i-Diz and Karun River, Iran; *A. persicus* (Nikolsky, 1907) from Shahrud, Iran; and *A. p. pannonicus* and *A. p. grayanus* [24]—in wide distribution range of *A. pannonicus*, that all species regarded to synonym *A. pannonicus* by Anderson [30].

The general aim of this chapter is (1) to identify potential areas of distribution during three periods of the past, last interglacial (LIG: ∼120,000–140,000 years BP) and mid-Holocene (MH: ∼6000 years BP), (2) to describe current (~1950– 2000) distribution and suitable habitat, and to understand the biogeographical patterns of the two mentioned species in Asia.

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**3. Results**

*Modeling the Past and Current Distribution and Habitat Suitability for Two Snake-eyed Skinks...*

The study area encompasses the whole Iranian territory. We assembled the species occurrence data for each species based on a systematic biological survey by walking randomly through the habitat from 09:00 to 12:00 AM and 15.00 PM to evening (much of the activity time of species) during spring to summer 2010 and 2015. We used localities mentioned in previous studies (e.g., Anderson [30]; Vyas [28]). *Ablepharus grayanus* specimens were collected, and their distribution data were recorded (34 recorded) from Sistan and Baluchestan and Kerman Provinces, southeastern Iran. We gathered distribution data of *A. pannonicus* specimens collected under rocks or leaves on the floor of oak forest in the Zagros Mountains and in between the meadow grass in the Darvishab River Park (Baghmalek, Khuzestan Province) and recorded the exact location using the global positioning system (GPS). In other areas (Esfahan, Ilam, Kermanshah, Khorasan Razavi, Kurdistan, Lorestan, Mazandaran, Qum, Semnan, Zanjan, and Yasuj Provinces), we observed *A. pannonicus* in between the grasslands, shrubs, and steppes, and exact coordinates

We implemented maximum entropy modeling (MaxEnt, 3.3.3e http://www. cs.princeton.edu/~schapire/MaxEnt) of species geographic distributions with default parameters of the data to test samples. We examined 19 bioclimatic variables

examined 19 bioclimatic variables in the past (LIG and MH) in the related part of the world (Asia) [32, 33] (www.worldclim.org) (see the Appendix). To identify the correlation ratios between variables and presence records, openModeller (V. 1.0.7) [34] was used. Then we used SPSS IBM (version 22) for Pearson correlation coefficient [17]. We selected variables with a Pearson correlation lower than 0.75 to choose the variables that are ecologically important for species separation according to our observations and to describe habitat [35]. We conducted MaxEnt software with 10 replicates of the analysis that yield the best model for the studied species. MaxEnt provides state distribution models by the receiver operating characteristic (ROC) plots; ROC curves plot true-positive rate against false-positive rate [21, 36]. A value of the area under the curve (AUC) of 0.5–0.7 is taken to indicate that the result is a stochastic prediction [37, 38], values of 0.7–0.9 suggest useful models, and the values more than 0.9 indicate high accuracy [39]. We used DIVA-GIS 7.3.0.1 software for the mean predicted map and a logistic output of present records with suitability ranging from zero (unsuitable habitat) to one (the best suitable habitat) [40].

The final models in the present study showed good match and closely fitted the presence of the two species recorded in the study areas, as suggested by high AUC values (*A. grayanus* = 0.929 ± 0.087 and *A. pannonicus* = 0.979 ± 0.007). Moreover, two variables contributed for both species (BIO3 and slope), six variables for *A. grayanus*, and six variables for *A. pannonicus* were detected separately (**Table 1**). The last models in the mid-Holocene simulated high AUC values (*A. grayanus* = 0.975 ± 0.019

precision (30 s × 30 s)

precision (5 min × 5 min); we also

and 2 topographical variables with grids approximately 1 km2

*DOI: http://dx.doi.org/10.5772/intechopen.82476*

were marked with GPS (108 recorded).

for contemporary (~1950–2000) and 10 km2

**2.2 Data set and analysis**

**2. Material and methods**

**2.1 Study area and records**

*Modeling the Past and Current Distribution and Habitat Suitability for Two Snake-eyed Skinks... DOI: http://dx.doi.org/10.5772/intechopen.82476*
