North-Bavarian local heat islands as a hideaway for thermophilic plant species

North-Bavarian local heat islands

The ecological effects of climate change appear globally in terms of loss of species. Beside phenological alternations, shifts in vegetation period and population dynamics, significant effects on species diversity are very likely to appear also at a regional scale. Whereas mobile species like most animals will be able to counteract climatic shifts e.g. by migration, most plants have only a restricted dispersal ability and thus will be not capable to deal with rapid climatic changes.

In this context, assisted migration, means the active translocation of species into regions, which are expected to be more suitable in the future, is the subject of heated debates in the current literature. Whereas numerous people consider assisted migration to be irresponsible in terms of regional nature conservation, others equate the active negligence of assisted migration with an active approval of regional species loss. However, little is known about the ecological effects of active translocation of species into foreign ecosystems. Therefore, active field research is needed to take the right decisions in terms of species conservation. Furthermore, results form this research will help to interpret results, which derives from biogeographical modelling. Current species distribution models only apply to zonal climatic conditions. Microclimatic peculiarities as well as a temporal restricted presence of such kind of favourable climatic conditions is still neglected in terms of species distribution modelling.

The monitoring of already established populations of foreign species in our landscape is the best way to answer the question about the effects of species introduction on local communities. Natural local heat islands in the landscape of northeastern Bavaria provide an excellent opportunity to study these effects. These special sites (mainly dry grassland) are favoured by warm local climatic conditions in comparison to the surrounding landscape and hosts numerous, thermophilic species, which were in parts already introduced in the 1960’s.

The major objective of our project is to assess the potential of this local heat island in Northern Bavaria as a hideaway for thermophilous exotic plant species. Therefore, the current abundance and distribution of foreign species will be mapped and compared to historical records. Furthermore, local climatic conditions will be monitored with high spatial and temporal resolution to reveal the major microclimatic drivers of exotic species continued existence in this area.