Grassland litter decomposition is accelerated by herbivore dung deposition via changes in bacterial communities

作者：Zhiyang Zhang, Xiaogang Dong, Jing Tang, Shiting Zhang, Riikka Rinnan, Yi Jiao · 发表于：Agriculture Ecosystems & Environment · 年份：2025 · DOI：10.1016/j.agee.2025.109557 · 被引用次数：11 · 研究领域：Soil Carbon and Nitrogen Dynamics、Peatlands and Wetlands Ecology、Coastal wetland ecosystem dynamics

The decomposition of herbivore dung and plant litter are two crucial ecological processes that maintain the biogeochemical cycles and functions of grazing grassland ecosystems. Herbivore dung deposition causes heterogeneous microenvironmental conditions (e.g., temperature, moisture, nutrients, and microbial activities), yet its influence on litter decomposition and the involved biotic and abiotic processes remains underexplored. This study conducted a three-year dung-litter decomposition experiment in a yak-grazed alpine pasture on the Tibetan Plateau to examine how dung deposition influences soil microclimate, litter chemical quality, extracellular enzyme activities, and microbial communities, and how these factors collectively regulate the decomposition of Elymus nutans litter, a dominant plant species in the region. Results showed that dung deposition accelerated litter mass loss by 22 %, primarily by enhancing the degradation of cellulose and hemicellulose. Dung deposition raised soil temperature by 1.5 °C and increased moisture content by 19 % on average, and enriched litter chemical quality by reducing the carbon to nitrogen (C: N) ratio and increasing N, dissolved organic C, and dissolved organic N content. It also boosted the activities of lignocellulose-degrading enzymes, including β-1,4-glucosidase (BG), β-1,4-xylosidase (BX), β-D-cellobiosidase (CBH), xylanase (XYL), peroxidase, and polyphenol oxidase. Changes in microbial communities were distinct: bacterial commu...