Heikkinen, R. | bioRxiv Science

bioRxiv2026

Interactive effects of land use change and climate drive the decline of a threatened boreal forest orchid in Finland

Land use and climate change are two of the greatest threats to biodiversity globally. However, their interactive effects remain poorly understood. In the boreal forest biome, where species are experiencing increasing pressures from forest management and climate change, improved understanding of these effects is urgently needed. Here, we assess the impacts of forest loss and both baseline and changing late spring climatic conditions on the extinction probability of a threatened boreal forest orchid, Calypso bulbosa. We use a unique dataset consisting of 1,006 C. bulbosa occurrence sites located in Finland, historical aerial images, and climatic data spanning the last 60 years. Our results reveal that forest loss, at the local rather than landscape-scale, and both the site-specific baseline climatic conditions and their change over time influence the extinction probability of C. bulbosa. These effects were mainly interactive with greater temporal increase in rainfall ameliorating and greater baseline rainfall exacerbating the negative effect of forest loss on the species persistence. Furthermore, greater baseline snow depth ameliorated this negative effect. We also found some statistical support for independent effects of baseline thermal sum and its change over time, but their ecological relevance was interpreted as minor. Overall, our results align with the expectation that forest loss can modify the exposure of forest-dependent species to climatic conditions, thus altering their vulnerability to climate change.

ecology↗

bioRxiv2024

The accelerating exposure of European protected areas to climate change

1.All ecosystems are affected by climate change, but differences in the pace of change will render some areas more exposed than others. Such spatial patterns of risk are important when assessing the continued functionality of protected area (PA) networks or planning for their expansion. Europe is undertaking an expansion of the PA network to cover 30% of its land and sea surface, but this must account for climate risk. Here, we estimate four metrics of future climate risk across Europe - local velocity, distance velocity, magnitude, and residence time - and assess the level of climate exposure of European PAs vs non-protected control sites. We also evaluate the intensity of climate risks on >1,000 European species of conservation concern, associated with Natura2000 sites. Our results show large spatial differences in climate change exposure across Europe, with faster pace and farther shifts in climate in the Boreal, Steppic, and Pannonian regions but slower changes in the Mediterranean, Alpine, Artic, and Macronesian regions. Climate change magnitude was higher for the Alpine, Mediterranean, and Steppic regions, implying large local differences between present and future climate. These spatial risk patterns were largely consistent across scenarios, but with up to three times higher risk under the most pessimistic vs the most optimistic scenario. Large variation in climate exposure for species of conservation concern was revealed, including 11 species which are highly dependent on Natura2000 sites and predicted to experience rapid climate change. Our results provide guidance for managing European PAs, and expanding their coverage, by pinpointing areas offering more stable climates. We emphasize the need for connectivity across the network, to support species adaption via range shifting. This is especially the case in areas facing high climate change magnitude but low climate velocity, implying that climate conditions similar to current ones will be found nearby.

ecology↗