Species Diversity Induces Idiosyncratic Effects on Litter Decomposition in a Degraded Meadow Steppe

Frontiers in Environmental Science

Nazim Hassan¹  Xuefeng Wu¹  Ling Wang¹  Liu Yiming¹  Iqra Naeem¹  Hongjun Wang²  Talal Asif³  Deli Wang⁴ 

[1] Institute of Grassland Science, Key Laboratory of Vegetation Ecology, Northeast Normal University, Changchun, China;Nicholas School of the Environment, Duke University Wetland Center, Durham, NC, United States;Peatland Ecology Research Group (PERG), Centre for Northern Studies, Department of Plant Sciences, Université Laval, Québec, QC, Canada;School of Environment/Key Laboratory of Vegetation Ecology, Northeast Normal University, Changchun, China;

关键词: litter mixing;    nutrient cycling;    litter quality;    evenness;    non-additive effects;    incubation time;   

DOI  :  10.3389/fenvs.2021.582409

来源: DOAJ

【 摘 要 】

Litter decomposition is a fundamental path for nutrient cycling in a natural ecosystem. However, it remains unclear how species diversity, including richness and evenness, affects the decomposition dynamics in the context of grassland degradation. Using a litter bag technique, we investigated the litter-mixing effects of two coexisting dominant species (Leymus chinensis Lc and Phragmites australis Pa), as monocultures and mixtures with evenness (Lc:Pa) from M1 (30:70%), M2 (50:50%), and M3 (70:30%), on decomposition processes over time (60 and 365 days). The litter bags were placed on the soil surface along a degradation gradient [near pristine (NP), lightly degraded (LD), and highly degraded (HD)]. We found that 1) mass loss in mixture compositions was significantly and positively correlated with initial nitrogen (N) and cellulose contents; 2) litter mixing (richness and evenness) influenced decomposition dynamics individually and in interaction with the incubation days and the degradation gradients; 3) in a general linear model (GLM), nonadditive antagonistic effects were more prominent than additive or neutral effects in final litter and nutrients except for carbon (C); and 4) in nutrients (C, N, lignin) and C/N ratio, additive effects shifted to nonadditive with incubation time. We speculated that the occurrence of nonadditive positive or negative effects varied with litter and nutrients mass remaining in each degraded gradient under the mechanism of initial litter quality of monoculture species, soil properties of experimental sites, and incubation time. Our study has important implications for grassland improvement and protection by considering species biodiversity richness, as well as species evenness.

【 授权许可】

Unknown