Population Study of the Grass Snake in the Rieselfelder Münster: A Methodological Approach

Rief C

Zusammenfassung

Due to fragmentation and intensive agricultural use of lansdcapes, many species are declining. To enable their preservation, information about their distribution and ecology is required. Reptiles, particularly snakes, live rather secretive and therefore apply to be difficult to investigate. However, several surveying methods have been deloped. It was the aim of this study to investigate the efficiency and practicability of three methods and to test if they are adequate for future surveys of grass snakes (Natrix natrix) in a nature reserve containing many wetland zones, the Rieselfelder Münster, or similar areas. The three methods applied were the usage of artifical refuges, visual encounter surveys and a public call for reporting grass snake sightings. The former was especially examined regarding the comparison between the usage of two or more refuges close to each other (clustering) and single refuges. It was observed that clustering led to more efficient controls regarding the number of snakes captured. Furthermore, it was detected that more socialization of N. Natrix with conspecifics and slow worms (Anguis fragilis) occurred beneath clustered refuges than beneath single ones. Visual encounter survey and public call were applied to reveal a more precise distribution pattern and fulfilled this task. However, for future studies only the continuation of the public call is recommended. It led to additional information without much investment, whereas the visual encounter survey was very time-consuming.