This project assesses for several cantons the sensitivity of (mostly) plants and animals to expected climatic changes. The assessments rely on the current distribution of the species and their so called indicator-values that are assessed at the community-level. Results indicate whether climatic changes are rather threatening, may act neutrally, or may even favor certain species.
The aim of this study is to identify plant and/or animal species that are potentially threatened or promoted by climate change in Switzerland. In addition, localities with relatively large proportions of potentially threatened or promoted species are to be identified. For this purpose, a simple model using indicator values is created, which can be used to generate an initial list of potentially threatened or promoted species. This list is then further differentiated into "rather threatened/promoted" and "of little relevance" on the basis of expert knowledge.
The methodology in more detail
Indicator values are one way of assessing the climate impact on animal and plant species in Switzerland. Indicator values are mainly based on expert and literature knowledge and are available for every Swiss species and several ecological factors (temperature, soil moisture, etc.) on an ordered, qualitative scale. The indicator values indicate the preferred climatic and site conditions for each species. Hence, they describe some sort of optimal condition under which a species thrives best or is most likely to be found in nature.
One cannot interpret the indicator value of a species in terms of whether a species X finds more or less suitable conditions at site Y without knowing the value of the site. The averaged values of a site, say, for temperature, of all occurring species are used to determine the ecological conditions at a site.
Some species at a given site show higher, other lower indicator values, indicating that they prefer, say, higher or lower temperatures than the temperature effectively prevailing at the site. Such species may be more threatened at this location under climate change if the mean temperature of the location is higher than that of these species. So when it gets even warmer, the climatic conditions at this location will be even further away from the optimal conditions of these species. We can say that the more a species deviates from the mean value of the site for temperature or humidity, the more the species will be threatened or promoted at this site if climate change leads to higher temperatures and decreasing humidity.
In this project we use the indicator values temperature and humidity, assuming that the temperature rises and the humidity decreases due to climate change, especially in the summer half-year, the most important season for animal and plant species. We use specific limits to determine how far the indicator value of a species must be from the mean value of a site in order to be considered potentially threatened or promoted at this site if the temperature increases or if it becomes drier. A provisional list of potentially endangered and promoted species generated in this way is then further differentiated into "rather threatened/promoted" and "of little relevance" on the basis of expert knowledge.