Modelling future collapse risk of aapa mires across a boreal climate gradient

Northern peatlands provide critical ecosystem services, including carbon sequestration that mitigates climate change. Warming and land use threaten many peatlands, but a unique subclass of peatlands called aapa mires are currently listed as Least Concern in Europe. We aimed to evaluate risk for aapa mires in Finland using newly available datasets. We developed a new remote sensing-based indicator of aapa mire degradation and used forecasting models integrating climate change, hydrology, and peat mining scenarios to estimate trajectories of degradation in mire ecosystems to 2099. We modelled 120 Finnish aapa mires across three climate zones and used our results to assess risk against the global standard IUCN Red List of Ecosystems (RLE) criteria. We found substantial historical degradation, although this has slowed with the cessation of unsustainable land use practices since the late 1900s. Projected climate change produced moderately elevated risk; however, risk increased rapidly under intensifying peat mining scenarios. Aapa mires in the south boreal region had the highest risk of collapse, with a mean probability of collapse of 20.3% over a 50-year period (2025 to 2075), compared to 5.0% in the middle boreal and 1.6% in the northern boreal zones. Under the RLE criteria, northern and middle-boreal mires were Vulnerable and southern mires were Critically Endangered under Criterion C3 (historical environmental degradation). Conservation of core areas, refraining from mining, and restoration of degraded sites are essential, as remaining aapa mires provide critical wildlife refugia, and those undergoing natural succession processes offer climate mitigation potential.