Distribution and hybridisation of barred and common grass snakes (Natrix helvetica, N. natrix) in Baden-Württemberg, South-western Germany

By

Schultze, Nadine
Laufer, Hubert
Kindler, Carolin
Fritz, Uwe

Type

Article

Date of Publication

2019-10-4

Original Publication

Subterranean Biology

Volume

32

Pages

229--236

Subjects

cline analysis , gene flow , hybrid zone , Natricidae , Serpentes

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/herpetozoa.32.e38897

 

Abstract

The distribution and hybridisation zone of the two grass snake species occurring in the German state of Baden-Württemberg are described, based on genetic data from maternally inherited mitochondrial DNA (mtDNA, up to 1983 bp) and biparentally inherited microsatellite DNA (13 loci). In agreement with previously published morphological evidence, the barred grass snake (Natrix helvetica) occurs in the Upper Rhine Valley and the Black Forest, while the common grass snake (N. natrix, ‘yellow lineage’) is distributed across the remaining, more eastern parts of Baden-Württemberg. Cline analyses across two transects running through the region of Karlsruhe and the Black Forest indicate that the hybrid zone is similarly narrow here as in the previously characterised stretch near Lake Constance. With respect to nuclear DNA, the Black Forest constitutes no impediment to gene flow in comparison with lowland regions (Karlsruhe, Lake Constance). However, on the eastern slope of the Black Forest, the abrupt replacement of mtDNA ofN. helveticaby that ofN. natrixindicates male-mediated gene flow and that the Black Forest represents a dispersal barrier for female grass snakes.