Tremblay Junior A, Boulanger Yan, Cyr Dominic, Taylor Anthony R, Price David T, St-Laurent Martin-Hugues
Sciences and Technology Branch, Environment and Climate Change Canada, Québec, Québec, Canada.
Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Stn. Sainte-Foy, Québec, Québec, Canada.
PLoS One. 2018 Feb 7;13(2):e0191645. doi: 10.1371/journal.pone.0191645. eCollection 2018.
Many studies project future bird ranges by relying on correlative species distribution models. Such models do not usually represent important processes explicitly related to climate change and harvesting, which limits their potential for predicting and understanding the future of boreal bird assemblages at the landscape scale. In this study, we attempted to assess the cumulative and specific impacts of both harvesting and climate-induced changes on wildfires and stand-level processes (e.g., reproduction, growth) in the boreal forest of eastern Canada. The projected changes in these landscape- and stand-scale processes (referred to as "drivers of change") were then assessed for their impacts on future habitats and potential productivity of black-backed woodpecker (BBWO; Picoides arcticus), a focal species representative of deadwood and old-growth biodiversity in eastern Canada. Forest attributes were simulated using a forest landscape model, LANDIS-II, and were used to infer future landscape suitability to BBWO under three anthropogenic climate forcing scenarios (RCP 2.6, RCP 4.5 and RCP 8.5), compared to the historical baseline. We found climate change is likely to be detrimental for BBWO, with up to 92% decline in potential productivity under the worst-case climate forcing scenario (RCP 8.5). However, large declines were also projected under baseline climate, underlining the importance of harvest in determining future BBWO productivity. Present-day harvesting practices were the single most important cause of declining areas of old-growth coniferous forest, and hence appeared as the single most important driver of future BBWO productivity, regardless of the climate scenario. Climate-induced increases in fire activity would further promote young, deciduous stands at the expense of old-growth coniferous stands. This suggests that the biodiversity associated with deadwood and old-growth boreal forests may be greatly altered by the cumulative impacts of natural and anthropogenic disturbances under a changing climate. Management adaptations, including reduced harvesting levels and strategies to promote coniferous species content, may help mitigate these cumulative impacts.
许多研究通过依赖相关物种分布模型来预测未来鸟类的分布范围。这类模型通常没有明确体现与气候变化和采伐相关的重要过程，这限制了它们在景观尺度上预测和理解北方鸟类群落未来的潜力。在本研究中，我们试图评估采伐和气候引发的变化对加拿大东部北方森林野火和林分水平过程（如繁殖、生长）的累积和特定影响。然后评估这些景观和林分尺度过程（称为“变化驱动因素”）的预测变化对未来栖息地以及黑背啄木鸟（BBWO；Picoides arcticus）潜在生产力的影响，黑背啄木鸟是加拿大东部枯木和老龄林生物多样性的代表性重点物种。使用森林景观模型LANDIS-II模拟森林属性，并用于推断在三种人为气候强迫情景（RCP 2.6、RCP 4.5和RCP 8.5）下与历史基线相比，未来景观对黑背啄木鸟的适宜性。我们发现气候变化可能对黑背啄木鸟不利，在最恶劣的气候强迫情景（RCP 8.5）下，潜在生产力可能下降高达92%。然而，在基线气候条件下也预计会有大幅下降，这凸显了采伐在决定未来黑背啄木鸟生产力方面的重要性。当今的采伐方式是老龄针叶林面积减少的唯一最重要原因，因此，无论气候情景如何，它似乎都是未来黑背啄木鸟生产力的唯一最重要驱动因素。气候引发的火灾活动增加将进一步促进幼龄落叶林的生长，而老龄针叶林则会减少。这表明，在气候变化的情况下，与枯木和北方老龄林相关的生物多样性可能会因自然和人为干扰的累积影响而发生巨大改变。管理适应性措施，包括降低采伐水平以及促进针叶树种含量的策略，可能有助于减轻这些累积影响。
