Xinhou Zhang, Wei Chen, Weixiang Chen, Xianwei Wang, Rong Mao
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引用次数: 0
Abstract
Litter decomposition plays an important role in biogeochemical cycling in boreal peatlands, where mosses, especially Sphagnum species, are a determinant. In recent decades, these peatlands have experienced a decline in moss cover due to abrupt climate warming and atmospheric nitrogen (N) deposition. To reveal the effect of the reduction in moss cover on litter decomposition, we adopted a field living moss removal experiment (with the senesced tissues remaining) in a Sphagnum-dominated boreal peatland, and investigated litter mass loss and net N loss of three deciduous woody species decomposing in monocultures and mixtures over 3 years. Based on the observed and predicted mass loss and net N loss of litter mixtures, we divided litter mixing effects into additive (no significant difference), synergistic (observed value greater than predicted value), and antagonistic (observed value lower than predicted value) effects. Across 3 years of decomposition, moss removal increased litter mass loss and net N loss, irrespective of single- or mixed-species compositions. Moss removal generally changed litter mixing effects on mass loss from antagonistic to additive effects in the initial 2 years, but from synergistic to additive effects after 3 years of decomposition. Regarding net N loss of litter mixtures, moss removal often resulted in a shift from additive to synergistic effects or from antagonistic to additive effects after 2 and 3 years of decomposition. Our observations suggest that the declines in living moss cover can accelerate litter decomposition and nutrient release, and highlight that living moss loss makes litter mixture decomposition predictable by reducing non-additive effects in boreal peatlands. Given the widespread occurrence of reduced moss cover in boreal peatlands, the mechanisms explaining living moss controls on litter decomposition and N cycling should receive significant attention in further studies.
期刊介绍:
Biogeochemistry publishes original and synthetic papers dealing with biotic controls on the chemistry of the environment, or with the geochemical control of the structure and function of ecosystems. Cycles are considered, either of individual elements or of specific classes of natural or anthropogenic compounds in ecosystems. Particular emphasis is given to coupled interactions of element cycles. The journal spans from the molecular to global scales to elucidate the mechanisms driving patterns in biogeochemical cycles through space and time. Studies on both natural and artificial ecosystems are published when they contribute to a general understanding of biogeochemistry.