Natrix natrix

• Main Author: Elmberg, Johan
• Format: Other/Unknown Material
• Language: unknown
• Published: 2023
• Subjects: Biodiversity; Taxonomy; Animalia; Chordata; Reptilia; Squamata; Natricidae; Natrix; Natrix natrix; North Sweden
• Online Access: https://zenodo.org/record/8030432; https://doi.org/10.5281/zenodo.8030432

Grass Snake Natrix natrix (Linneaus 1758) Distribution (Figure 9). Included records from Artportalen (N=200): all reports from Gästrikland, Hälsingland, and coastal Medelpad (where widespread). Reports from other areas have been included only if documentation was available. This species and black morph Vipera berus are widely confused, even among naturalists. Occurs throughout the Southern Boreal. Widespread and fairly common in Gästrikland and coastal Hälsingland, local and scarce in interior Hälsingland and coastal Medelpad. There is a disjunct well-documented record at 480 m altitude in central Härjedalen, in the Northern Boreal region (Figure 9). This is by far the highest known record, whereas the 2 nd to 4 th highest in North Sweden were all made at 180 m or lower. For the former extraordinary record there is no obvious suspicion of anthropogenic spread. However, well-documented records north of the present range (filled black circles in the map) can all be suspected to have anthropogenic origin, and none represents permanent presence or a reproducing population. Although the species is an excellent swimmer there are just two records on offshore islands off the Baltic coast of North Sweden (Limön and Eggegrund, both in Gästrikland). For the period 1900–1950, Gislén & Kauri (1959) listed many records in the Middle and Northern Boreal, far north and west of the known present range. Several were well documented, but it is not known whether those occurrences were relicts from a previously wider natural distribution, or the result of anthropogenic activities such as long-distance transport of hay and manure (Elmberg 1995). As late as the late 1960’s there were confirmed records in several places around Umeå (Västerbotten, Middle Boreal; Stefan Ericsson personal communication), an area where the species has not been documented since. During the last 50 years, though, there have not been any indications of changes in distribution. Habitat and movements. Found in open places providing shelter, such as tall ...