Climate and other global environmental changes are major threats to ecosystem functioning and biodiversity. However, the importance of plant diversity in mitigating the responses of functioning of natural ecosystems to long-term environmental change remains unclear. Using inventory data of boreal forests of western Canada from 1958 to 2011, we found that aboveground biomass growth increased over time in species-rich forests but decreased in species-poor forests, and importantly, aboveground biomass loss from tree mortality was smaller in species-rich than species-poor forests. A further analysis indicated that growth of species-rich (but not species-poor) forests was statistically positively associated with rising CO 2 , and that mortality in species-poor forests increased more as climate moisture availability decreased than it did in species-rich forests. In contrast, growth decreased and mortality increased as the climate warmed regardless of species diversity. Our results suggest that promoting high tree diversity may help reduce the climate and environmental change vulnerability of boreal forests.
Bibliographical noteFunding Information:
We appreciate the Forest Management Branch of Alberta Ministry of Sustainable Resource Development and the Forestry Branch of Saskatchewan Renewable Resources for providing detailed data. We also thank Dr. Yong Luo for his assistance in data compilation and Dr. David A. Wardle for his critical comments to improve the manuscript. The study was supported by the Natural Sciences and Engineering Research Council of Canada (RGPIN-2014-0418 and STPGP 506284). M.H. thanks the Government of Ontario for an Ontario Trillium Scholarship, and E.B.S thanks the Natural Sciences and Engineering Council of Canada for an Alexander Graham Bell award.
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- Biodiversity–ecosystem functioning (B-EF)
- climate change impacts
- net aboveground biomass change
- tree species diversity