Chavardès Raphaël D, Gennaretti Fabio, Grondin Pierre, Cavard Xavier, Morin Hubert, Bergeron Yves
Institut de Recherche sur les Forêts, Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, QC, Canada.
Groupe de Recherche en Écologie de la MRC-Abitibi, Université du Québec en Abitibi-Témiscamingue, Amos, QC, Canada.
Front Plant Sci. 2021 Apr 29;12:658880. doi: 10.3389/fpls.2021.658880. eCollection 2021.
We investigated whether stand species mixture can attenuate the vulnerability of eastern Canada's boreal forests to climate change and insect epidemics. For this, we focused on two dominant boreal species, black spruce [ (Mill.) BSP] and trembling aspen ( Michx.), in stands dominated by black spruce or trembling aspen ("pure stands"), and mixed stands (M) composed of both species within a 36 km study area in the Nord-du-Québec region. For each species in each stand composition type, we tested climate-growth relations and assessed the impacts on growth by recorded insect epidemics of a black spruce defoliator, the spruce budworm (SBW) [ (Clem.)], and a trembling aspen defoliator, the forest tent caterpillar (FTC; Hübn.). We implemented linear models in a Bayesian framework to explain baseline and long-term trends in tree growth for each species according to stand composition type and to differentiate the influences of climate and insect epidemics on tree growth. Overall, we found climate vulnerability was lower for black spruce in mixed stands than in pure stands, while trembling aspen was less sensitive to climate than spruce, and aspen did not present differences in responses based on stand mixture. We did not find any reduction of vulnerability for mixed stands to insect epidemics in the host species, but the non-host species in mixed stands could respond positively to epidemics affecting the host species, thus contributing to stabilize ecosystem-scale growth over time. Our findings partially support boreal forest management strategies including stand species mixture to foster forests that are resilient to climate change and insect epidemics.
我们研究了林分物种混合是否能降低加拿大东部北方森林对气候变化和昆虫疫情的脆弱性。为此，我们聚焦于北方两种优势树种，黑云杉[（密尔.）BSP]和颤杨（米契尔.），研究对象包括以黑云杉或颤杨为主的林分（“纯林”），以及在魁北克省北部地区一个36公里的研究区域内由这两个树种组成的混交林（M）。对于每种林分组成类型中的每个树种，我们测试了气候与生长的关系，并通过记录一种黑云杉食叶害虫云杉芽虫（SBW）[（克莱姆.）]和一种颤杨食叶害虫森林天幕毛虫（FTC；许布恩.）的昆虫疫情，评估其对生长的影响。我们在贝叶斯框架下实施线性模型，以根据林分组成类型解释每个树种树木生长的基线和长期趋势，并区分气候和昆虫疫情对树木生长的影响。总体而言，我们发现混交林中黑云杉的气候脆弱性低于纯林，而颤杨对气候的敏感度低于云杉，并且颤杨在基于林分混合的响应上没有差异。我们没有发现混交林对寄主物种昆虫疫情的脆弱性有任何降低，但混交林中的非寄主物种可能对影响寄主物种的疫情做出积极反应，从而有助于随着时间推移稳定生态系统尺度的生长。我们的研究结果部分支持了北方森林管理策略，包括林分物种混合，以培育对气候变化和昆虫疫情具有恢复力的森林。
