Litter chemical traits strongly drove the carbon fractions loss during decomposition across an alpine treeline ecotone

Lifeng Wang; Yamei Chen; Yu Zhou; Haifeng Zheng; Zhenfeng Xu; Bo Tan; Chengming You; Li Zhang; Han Li; Li Guo; Lixia Wang; Youyou Huang; Jian Zhang; Yang Liu

doi:10.1016/j.scitotenv.2020.142287

Litter chemical traits strongly drove the carbon fractions loss during decomposition across an alpine treeline ecotone

Sci Total Environ. 2021 Jan 20:753:142287. doi: 10.1016/j.scitotenv.2020.142287. Epub 2020 Sep 8.

Authors

Lifeng Wang¹, Yamei Chen², Yu Zhou¹, Haifeng Zheng³, Zhenfeng Xu¹, Bo Tan¹, Chengming You¹, Li Zhang¹, Han Li¹, Li Guo⁴, Lixia Wang¹, Youyou Huang², Jian Zhang⁵, Yang Liu⁶

Affiliations

¹ National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River, Sichuan Province Key Laboratory of Ecological Forestry Engineering on the Upper Reaches of the Yangtze River, Long-term Research Station of Alpine Forest Ecosystems, Institute of Ecology & Forestry, Sichuan Agricultural University, Chengdu 611130, China.
² Key Laboratory of Southwest China Wildlife Resources Conservation, China West Normal University, Ministry of Education, Nanchong, Sichuan 637009, China.
³ Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark.
⁴ College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130, China.
⁵ National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River, Sichuan Province Key Laboratory of Ecological Forestry Engineering on the Upper Reaches of the Yangtze River, Long-term Research Station of Alpine Forest Ecosystems, Institute of Ecology & Forestry, Sichuan Agricultural University, Chengdu 611130, China. Electronic address: sicauzhangjian@163.com.
⁶ National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River, Sichuan Province Key Laboratory of Ecological Forestry Engineering on the Upper Reaches of the Yangtze River, Long-term Research Station of Alpine Forest Ecosystems, Institute of Ecology & Forestry, Sichuan Agricultural University, Chengdu 611130, China. Electronic address: sicauliuyang@163.com.

PMID: 33207458
DOI: 10.1016/j.scitotenv.2020.142287

Abstract

The decomposition of litter carbon (C) fraction is a major determinant of soil organic matter pool and nutrient cycling. However, knowledge of litter chemical traits regulate C fractions release is still relatively limited. A litterbag experiment was conducted using six plant functional litter types at two vegetation type (coniferous forest and alpine shrubland) in a treeline ecotone. We evaluated the relative importance of litter chemistry (i.e. Nutrient, C quality, and stoichiometry) on the loss of litter mass, non-polar extractables (NPE), water-soluble extractables (WSE), acid-hydrolyzable carbohydrates (ACID), and acid-unhydrolyzable residue (AUR) during decomposition. Litter nutrients contain nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sodium (Na), magnesium (Mg), aluminium (Al), manganese (Mn), zinc (Zn), iron (Fe) and copper (Cu), litter C quality contains C, WSE, NPE, ACID, and AUR, and stoichiometry was defined by C:N, C:P; N:P, ACID:N, and AUR:N. The results showed single exponential model fitted decomposition rates of litter mass and C fractions better than double exponential or asymptotic decomposition, and the decomposition rates of C fractions were strongly correlated with initial litter nutrients, especially K, Na, Ca. Furthermore, the temporal dynamics of litter nutrients (Ca, Mg, Na, K, Zn, and Fe) strongly regulated C fractions loss during the decomposition process. Changes in litter C quality had an evident effect on the degradation of ACID and AUR, supporting the concept of "priming effect" of soluble carbon fraction. The significant differences were found in the release of NPE, WSE, and ACID rather than AUR among coniferous forest and alpine shrubland, and the vegetation type effects largely depend on the changes in litter stoichiometry, which is an important implication for the change in plant community abundance regulate decay. Collectively, elucidating the hierarchical drivers of litter chemistry on decomposition is critical to soil C sequestration in alpine ecosystems.

Keywords: Alpine treeline ecotone; Carbon fractions; Litter chemistry; Litter decomposition; Vegetation type.