气候变化领域集成服务门户(CCPortal): Topmost trees and foremost species underlie tropical forest structure, diversity and biomass through opposing mechanisms

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DOI	10.1016/j.foreco.2020.118299
	Topmost trees and foremost species underlie tropical forest structure, diversity and biomass through opposing mechanisms
	Ali A.; Mattsson E.; Nissanka S.P.; Wang L.-Q.
发表日期	2020
ISSN	0378-1127
卷号	473
英文摘要	Tropical forests play a main role in the global carbon cycle due to their higher exchange capacity of carbon dioxide with the atmosphere than any other forest type on the Earth. In this study, we aimed to explore the relative importance of foremost species and topmost trees in shaping forest structure, diversity and biomass in natural tropical forests. We hypothesized that topmost trees promote but foremost species decline tropical forest structure, diversity and biomass in a changing environment (i.e. the ‘tree overtopping hypothesis’). We formulated three questions to address the proposed hypothesis: (1) Are forest structure, diversity and biomass affected by both foremost species and topmost trees, and what is the magnitude and direction of each relative effect? (2) Are foremost species and topmost trees influenced similarly by multiple environmental factors? (3) How do foremost species and topmost trees mediate the feedbacks of forest structure, diversity and biomass to environmental factors? Using 189 plots data from Sri Lanka, we quantified 16 environmental (9 climate and 7 soil) factors, two indices of the topmost trees (i.e. top 1% large-diameter, and tall-stature) and their combination, four indices of foremost species (i.e. top 1% species' importance value index or each of its three components including either relative basal area, relative frequency or relative density), rarefied species richness, and stand density. We used structural equation modeling to test the proposed hypothesis. Strong positive effects of topmost trees whereas negative to negligible positive effects of foremost species shaped tropical forest structure, diversity and biomass through opposing mechanisms, i.e., the promoting part of big trees and suppressing part of dominant species, respectively. Moreover, forest structure promoted biomass directly and indirectly via forest diversity. Environmental factors (i.e. high climatic water and low soil fertility) increased forest structure, diversity and biomass indirectly via topmost trees but decreased via foremost species. The main novelty or contribution of this study determines that the adverse effects of few foremost (i.e. dominant or abundant) species shaped forest structure, diversity and biomass in tropical forests when simultaneously considered the positive effects of topmost trees. Hence, encouraging topmost trees while managing foremost species might necessarily increase complementarity resource-use within a forest community, leading to positive forest diversity – structure – biomass relationships. We argue that both topmost trees and foremost species might have important influences on forest carbon stock in the context of global climate change. © 2020 Elsevier B.V.
关键词	Biomass Carbon dioxide Climate change Earth atmosphere Tropics Changing environment Environmental factors Exchange capacities Global carbon cycle Global climate changes Relative density Relative frequencies Structural equation modeling Forestry aboveground biomass carbon cycle carbon dioxide environmental factor forest management hypothesis testing species diversity stand structure tropical forest Biomass Capacity Carbon Dioxide Density Forestry Forests Trees Tropics Sri Lanka
语种	英语
来源机构	Forest Ecology and Management
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/132725
推荐引用方式 GB/T 7714	Ali A.,Mattsson E.,Nissanka S.P.,et al. Topmost trees and foremost species underlie tropical forest structure, diversity and biomass through opposing mechanisms[J]. Forest Ecology and Management,2020,473.
APA	Ali A.,Mattsson E.,Nissanka S.P.,&Wang L.-Q..(2020).Topmost trees and foremost species underlie tropical forest structure, diversity and biomass through opposing mechanisms.,473.
MLA	Ali A.,et al."Topmost trees and foremost species underlie tropical forest structure, diversity and biomass through opposing mechanisms".473(2020).