Climate change and land use threats to species of aapa mires, an EU priority habitat

Aapa mires are EU priority habitats that harbour unique biodiversity values but face increasing global change threats. Here, we investigate the exposure of red-listed aapa mire species inhabiting fen and flark fen habitats to the impacts of land use and climate change. Climate change-based threats were assessed across the aapa mire zone of Finland based on climate velocities (a metric describing the speed and direction of climate movement) measured for mean January temperature (TJan), growing degree days (GDD5) and mean annual water balance (WAB). Land use threats were assessed based on the cover of drainage ditches and three other adverse land use types around the species occurrences. Our results suggest that rapid changes in TJan may alter winter thermal conditions and thereby also species performance, particularly in the northernmost part of the aapa mire zone, where the most valuable concentrations of red-listed species are situated. The land use and GDD5 threats are highest in the southern regions where the red-listed aapa mire species occurrences are sparser but face severe risks to their persistence. In the central part of the aapa mire zone, a number of valuable aapa mires with red-listed species are exposed to both intermediately high TJan and GDD5 velocities and a spatially varying amount of ditching. Three conservation approaches to support the persistence of red-listed aapa mire species: (i) restora-tion, (ii) establishment of new protected areas, and (iii) monitoring of the key habitats, should be flexibly and complementarily applied to the preservation of aapa mires subject to accelerating climate change.