Advanced niche models for British Columbia ecosystems reveal North American climate analogues and novel futures

The classification of forest ecosystems in British Columbia (BC) is well-defined and serves as a critical foundation for the effective management and conservation of forest resources. However, the challenges posed by climate change threaten the functionality and relevance of this classification system. Previous efforts to project suitable climate habitats for these ecosystem classes have primarily focused on plant-climate relationships within the province, limiting the ability to predict emerging climate habitats and their analogues beyond BC. In this study, we adopted an innovative approach by modeling each forest ecosystem class individually and then integrating the results to identify analogous climate habitats across North America that match those of BC's ecosystem classes. This approach also allowed us to project new climate habitats that are yet to arise in BC. Furthermore, we traced the trajectories of these ecosystem classes back to the Last Glacial Maximum (approximately 20,000 years ago) and examined their shifts under future climate scenarios. Our findings indicate that most forest ecosystem classes in BC have comparable climate habitats across North America, highlighting their representation of distinct climate niches that are not exclusive to the province. During the Last Glacial Maximum, these climate habitats were situated much further south and have progressively shifted northward over the millennia. Under projected future climates, this northward shift is expected to continue, with some ecosystem classes disappearing from BC while others expand significantly. Additionally, we identified regions in BC that are likely to experience novel climates in the future, potentially replacing the current climate habitats of some ecosystem classes. These insights offer a scientific foundation for developing adaptive forest management strategies to address the impacts of climate change. Strategies such as assisted migration, diversification of forest composition, monitoring, and adaptive management will be crucial for maintaining the resilience, biodiversity, and productivity of BC's forest ecosystems in the face of climate-related challenges.