Winteractiviteit en -verblijfplaatsen van de adder in Overijssel

De adder (Vipera berus) komt in Nederland voor in Limburg, Drenthe, Friesland, Groningen, Overijssel en op de Veluwe. De habitat bestaat uit open en half open gebieden. Dit zijn tegenwoordig meestal heide- en hoogveengebieden. Grootschalige beheer- en herstelmaatregelen van met name hoogveengebieden kunnen leiden tot vernietiging van overwinteringsplaatsen van adders. Voor een goede bescherming van adderpopulaties is het dus van belang om exact te weten waar de overwinteringsplaatsen (hibernacula) liggen. Dit is in Overijssel in twee gebieden onderzocht: het Beerzerveld en de Engbertsdijksvenen. Winteractivity and hibernacula of the European adder in the Province of Overijssel Maintaining the habitat of the European adder (Vipera berus) requires intensive management measures which could lead to the destruction of hibernacula. The locations of the viper’s hibernacula have been investigated in two areas. Adders were monitored in the spring and autumn and 27 vipers were tagged. This resulted in a total of 57 observations, indicating 32 hibernacula. Height in relation to the groundwater, the exposure and the vegetation structure are the predictive parameters. The data can be extrapolated to other areas and will provide guidance for management. Telemetry was used to find the vipers in the winter. Several dead vipers were found. It is assumed that high groundwater levels have them to leave their hibernaculum. Because it was warmer than 8oC for a long time, they could become active and start looking for another place. When temperatures dropped, they froze to death.