Vortrag, Jahrestreffen des AK Biogeographie im Verband der Geographen an Deutschen Hochschulen (VGDH), Trier: 07.05.2010 - 09.05.2010
Abstract:
An expanding volume of literature has demonstrated that climate change affects species distributions. However, effects of a changing climate on reptiles are relatively unexplored. Environmental alterations associated with climate change may be beneficial and adverse at the same time, and the long-term survival of reptile species may depend on the relative strength of these environmental changes. Lizards are the most species-rich group in Europe within the paraphylum “reptiles”. The projected increasing temperatures over Europe and the associated extension of the growing season will probably lead to an improvement of the climatic conditions for lizards in Europe and encourage a potential spread. Lizards of the genus Lacerta are European-wide protected by the Habitats Directive. Most of them are listed in Annex IV; some are also listed in Annex II. Here, we present preliminary modelling results of three lizards of the genus Lacerta that are relevant for Germany: sand lizard (Lacerta agilis), western green lizard (Lacerta bilineata) and eastern green lizard (Lacerta viridis). We modelled the climate envelopes of these species and projected their potential future distribution for 2051-2080, using Boosted Regression Trees and 32-fold geographically stratified cross-validation. We tried to integrate species specific dispersal abilities to visualize potential range expansions, range declines or range shifts, unlike most other studies that assume either no or unlimited dispersal. According to the models, the sand lizard appears to be a potential winner of climate change and could increase its range north-eastwards. In contrast, the western green lizard is a potential loser, and a disjunction of the distribution area seems possible. The eastern green lizard could gain distribution area but there is no clear directional shift. The protection responsibility in Germany and Europe may change with climate change. Shifts of the centres of distribution and the accompanying responsibilities for the species may lead to adaptation needs in nature conservation. Species of the Habitats Directive may also disperse into new countries where new responsibilities may occur. These new and decisive challenges will be discussed.