Litter decomposition in mountainous forest ecosystems is an essential process that affects carbon and nutrient cycling. However, the contribution of litter decomposition to terrestrial ecosystems is difficult to estimate accurately because of the limited comparability of different studies and limited data on local microclimatic and non‐climatic factors. Here, we designed a coordinated experiment within subtropical and tropical forests across ten mountains to evaluate variation in litter decomposition rates and stabilization. We tested whether elevations, soil microclimate, soil physiochemistry, tree species diversity, and microhabitat affect decomposition rates and stabilization by using the Tea bag index as a standardized protocol. We found that the associations of decomposition rates and stabilization with elevation and each environmental factor varied between mountains. Elevation significantly affected decomposition rates and stabilization in the western mountains, where soil microclimate also played a dominant role due to relatively cold environments. Across all mountains, decomposition rates decreased while stabilization increased with increasing elevation. In terms of microclimate, decomposition rates increased with increasing soil temperature and temperature variation during the growing season, whereas stabilization decreased with increasing soil temperature and moisture variation. In terms of non‐climatic factors, decomposition rates increased with increasing tree species diversity, whereas stabilization decreased with soil pH and slope. Our findings enhance the general understanding of how different factors control forest litter decomposition, highlighting the dominant role of soil microclimate in controlling carbon and nutrient cycling in cold environments and high elevations.

中文翻译：

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什么控制森林凋落物分解？跨十座山的协调分布式袋泡茶实验


山地森林生态系统中的凋落物分解是影响碳和养分循环的重要过程。然而，由于不同研究的可比性有限以及当地小气候和非气候因素的数据有限，很难准确估计凋落物分解对陆地生态系统的贡献。在这里，我们在十座山脉的亚热带和热带森林中设计了一项协调实验，以评估凋落物分解率和稳定性的变化。我们使用茶袋指数作为标准化方案，测试了海拔、土壤小气候、土壤理化、树种多样性和微生境是否影响分解速率和稳定性。我们发现，分解率和稳定性与海拔和每个环境因素的关联因山而异。海拔显着影响西部山区的分解速率和稳定性，由于相对寒冷的环境，土壤小气候也发挥了主导作用。在所有山脉中，随着海拔的升高，分解率降低，而稳定度增加。就小气候而言，分解速率随着生长季节土壤温度和温度变化的增加而增加，而稳定性随着土壤温度和水分变化的增加而降低。就非气候因素而言，分解率随着树种多样性的增加而增加，而稳定性随着土壤 pH 值和坡度的增加而降低。 我们的研究结果增强了对不同因素如何控制森林凋落物分解的总体理解，强调了土壤小气候在控制寒冷环境和高海拔地区碳和养分循环方面的主导作用。