Search Results (3)

The study represents the results of a long-term (2016 to 2021) survey on the herpetofauna inhabiting the vicinity of a heavily loaded section of the road E 87. The investigated road splits a Protected site from the net NATURA 2000 BG0000271 “Mandra-Poda”. The Protected site is known for its high biodiversity and its dense populations of vertebrates, which thrive in the area. Directly near the inspected road and on the pavement, we were able to detect five species of snakes, three species of turtles and two species of lizards. Among the squamates, rare observations were made of the European nose-horned viper (Vipera ammodytes), detected twice, and the European glass lizard (Pseudopus apodus), detected three times. Three other species—the Bloched snake (Elaphe sauromates), the Caspian whipsnake (Dolichophis caspius) and the Rhodos green lizard (Lacerta dyplochondrodes)—were found in larger numbers during some of the field surveys and here we provide information concerning the hot moments of their activity in the vicinity of the road. The Grass snakes (Natrix natrix) and the Dice snakes (N. tessellata) formed dense groups in the direct vicinity (closer than one and half meters) of the investigated road section. Despite the high number of recorded snakes and lizards, only isolated cases of vehicle collisions were observed. We suggest that the local squamate population had developed a complex of ethological specifics related to feeding, basking, shading, and copulation, which helped them to benefit from the road and avoid the risks related to the heavy traffic. Full article

Semi-natural environments within cities can provide habitats for vulnerable reptile species. Better understanding of their habitat use and home range sizes is important for their conservation. We investigated the spatial ecology of Caspian whipsnakes (Dolicophis caspius) in a peri-urban habitat in Budapest, Hungary. We used radiotelemetry to track five adult snakes and analyzed their microhabitat preferences, home range sizes and daily movements. The Caspian whipsnakes intensively utilized areas covered with woody vegetation, with a high density of hibernacula. The tracked snakes used an area of 40.15 ha during the activity period from spring to autumn, but for the winter, they withdrew to a central area of 1.75 ha, abundant in hibernacula. During the activity period the individual home range sizes varied between 6.1 and 15.5 ha, estimated using the minimum convex polygon (MCP); however, for the entire datasets of the individuals, the adaptive kernel method gave the highest mean (13.8 ha), while the LoCoH-R yielded the smallest home ranges (5.19 ha). We found that the average daily displacement for the different individuals ranged between 12.6 and 36.6 m during their main activity season. In the study area, the whipsnakes currently have enough space for foraging, but the restricted spatial distribution of hibernacula, which is mainly available in the central dry rocky forest and partly in the shrubby areas, can limit the extent of the suitable habitat. Human activities and anthropogenic disturbances, especially around hibernacula, may exert pressure on this peri-urban snake population. Full article

Across the distribution of the Caspian whipsnake (Dolichophis caspius), populations have become increasingly disconnected due to habitat alteration. To understand population dynamics and this widespread but locally endangered snake’s adaptive potential, we investigated population structure, admixture, and effective migration patterns. We took a landscape-genomic approach to identify selected genotypes associated with environmental variables relevant to D. caspius. With double-digest restriction-site associated DNA (ddRAD) sequencing of 53 samples resulting in 17,518 single nucleotide polymorphisms (SNPs), we identified 8 clusters within D. caspius reflecting complex evolutionary patterns of the species. Estimated Effective Migration Surfaces (EEMS) revealed higher-than-average gene flow in most of the Balkan Peninsula and lower-than-average gene flow along the middle section of the Danube River. Landscape genomic analysis identified 751 selected genotypes correlated with 7 climatic variables. Isothermality correlated with the highest number of selected genotypes (478) located in 41 genes, followed by annual range (127) and annual mean temperature (87). We conclude that environmental variables, especially the day-to-night temperature oscillation in comparison to the summer-to-winter oscillation, may have an important role in the distribution and adaptation of D. caspius. Full article