Aim: To evaluate current and future dynamics of 25 tree species spanning United States and Canada. Location: United States and Canada. Methods: We combine, for the first time, the species compositions from relative importance derived from the USA’s Forest Inventory Analysis (FIA) with gridded estimates based on Canada's National Forest Inventory (NFI-kNN))-based photo plot data to evaluate future habitats and colonization potentials for 25 tree species. Using 21 climatic variables under RCP 4.5 and RCP 8.5, we model climatic habitat suitability (HQ) within a consensus-based multimodel ensemble regression approach. A migration model is used to assess colonization likelihoods (CL) for ~100 years and combined with HQ to evaluate the various combinations of HQ + CL outcomes for the 25 species. Results: At a continental scale, many species in the conterminous United States lose suitable climatic habitat (especially under RCP 8.5) while Canada and USA's Alaska gain climate habitat. For most species, even under optimistic migration rates, only a small portion of overall future suitable habitat is projected to be naturally colonized in ~100 years, although considerable variation exists among species. Main conclusions: For the species examined here, habitat losses were primarily experienced along southern range limits, while habitat gains were associated with northern range limits (especially under RCP 8.5). However, for many species, southern range limits are projected to remain relatively intact, albeit with reduced habitat quality. Our models predict that only a small portion of the climatic habitat generated by climate change will be colonized naturally by the end of the current century—even with optimistic tree migration rates. However, considerable variation among species points to the need for significant management efforts, including assisted migration, for economic or ecological reasons. Our work highlights the need to employ range-wide data, evaluate colonization potentials and enhance cross-border collaborations.

中文翻译：

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结合美国和加拿大的森林清单，评估气候变化下 25 种树种的栖息地适宜性和迁移潜力

目标：评估跨越美国和加拿大的 25 种树种的当前和未来动态。地点：美国和加拿大。方法：我们首次将来自美国森林清单分析 (FIA) 的相对重要性的物种组成与基于加拿大国家森林清单 (NFI-kNN) 的网格估计相结合，以评估未来的栖息地和 25 种树种的定殖潜力。使用 RCP 4.5 和 RCP 8.5 下的 21 个气候变量，我们在基于共识的多模型集成回归方法中对气候栖息地适宜性 (HQ) 进行建模。迁移模型用于评估约 100 年的定殖可能性 (CL)，并结合 HQ 评估 25 个物种的 HQ + CL 结果的各种组合。结果：在大陆范围内，美国本土的许多物种失去了合适的气候栖息地（尤其是在 RCP 8.5 下），而加拿大和美国的阿拉斯加则获得了气候栖息地。对于大多数物种来说，即使在乐观的迁徙率下，预计未来 100 年内只有一小部分整体未来适宜栖息地会自然定居，尽管物种之间存在相当大的差异。主要结论：对于这里检查的物种，栖息地丧失主要发生在南部范围限制，而栖息地增加与北部范围限制有关（特别是在 RCP 8.5 下）。然而，对于许多物种而言，虽然栖息地质量下降，但预计南部范围限制将保持相对完整。我们的模型预测，到本世纪末，气候变化产生的气候栖息地中只有一小部分会被自然殖民——即使树木迁移率乐观。然而，物种之间的巨大差异表明，出于经济或生态原因，需要进行大量管理工作，包括协助迁移。我们的工作强调了使用范围广泛的数据、评估殖民潜力和加强跨境合作的必要性。