High-latitude EU Habitats Directive species at risk due to climate change and land use

Abstract

The Habitats Directive of the European Union is a key legislative instrument in Europe, supporting the conservation of rare, threatened or endemic species. It aims at ensuring that the species listed in the Annexes of the Habitats Directive show a favourable conservation status, i.e., that they are able to maintain viable populations and that their natural range is sufficient and not decreasing currently, nor will in the future. However, climate change may hamper Habitats Directive species in achieving (or maintaining) a favourable conservation status, particularly when these impacts are amplified by adverse land use. Here, we studied Habitats Directive species in Finland for which ≥70% of the occurrences were recorded with the resolution of ≤100 m. The number of occurrence sites for the 52 species studied ranged from one site to 13,653 sites, summing up to 19,367 sites. For all these sites and their surroundings, we assessed the vulnerabilities caused by climate change and land use. The climate exposure of occurrence sites was measured based on the rapidity of climatic changes (i.e. climate velocity) in three climate variables (growing degree days, mean January air temperature, water balance) at each site. Risks caused by land use were assessed using two negative and four positive variables that respectively described the quantity of land cover and habitats that is either harmful (e.g. clear-cut forest and drained peatlands) or supportive (protected areas and suitable habitats) to species occurrences. To complement climate and land-use variables, three additional variables describing protection status of the sites and the number of occurrences of the same species in the landscape were examined. Comparison of the mean vulnerability values for each species showed that some of the species inhabit, on average, areas with high climate exposure. Moreover, in certain species climate change-induced vulnerabilities consistently coincide with negative land use. However, in many of the 52 species there was large variation in the vulnerability levels between individual occurrence sites, concerning both climate exposure and land-use variables. Considering the vulnerabilities due to climate change separately, 40–60% of the species occurrence sites are expected to face high exposure caused by rapid changes in summer or winter temperatures, which presents challenges in maintaining a favourable conservation status. Our results also revealed numerous species occurrences where high climate velocity coincided with a large amount of negative land use and low amount of suitable habitat, for which climate-wise conservation planning could be targeted.