枯落物的分解是草本沼泽湿地生态系统中重要的生物地球化学过程，放牧是人类活动影响湿地环境的主要方式。因此，研究放牧对湿地枯落物分解特征的影响，对于理解湿地生态系统的物质循环及能量流动具有重要意义。本研究以吉林省东部图们江下游草本沼泽湿地为研究对象，分析不同放牧管理模式（天然无牧、放牧处理、围封禁牧）对湿地主要功能群的代表性植物（莎草科的灰脉薹草和禾本科的菰）分解特征的影响，并研究土壤环境因子和枯落物基质质量对枯落物分解的作用机制。

      通过对天然无牧湿地、放牧处理湿地与围封禁牧湿地的对比分析，揭示了不同管理方式对枯落物分解速率、养分释放模式的显著差异。具体而言，天然无牧湿地表现出较高的枯落物分解速率，突显了自然状态对生态系统养分循环的积极作用。相比之下，放牧处理虽然在初期加速了枯落物分解，但在后期却明显落后于围封禁牧处理，反映了不同阶段湿地管理模式对枯落物分解速率的差异性影响。进一步比较灰脉薹草和菰的养分含量，发现灰脉薹草具有较高的全碳、全磷、木质素含量，而其分解时间却远大于菰，表明枯落物含有较高的纤维素和较低的木质素含量时，有利于加速分解过程。而土壤环境因子，如水位、土壤温度、土壤电导率和土壤养分，也对枯落物分解过程和质量残余量产生显著影响，进一步凸显了湿地管理模式和土壤环境对枯落物分解的综合影响。

       利用结构方程模型，发现放牧主要会通过影响土壤的理化性质对枯落物的残余量产生间接的影响。比较灰脉薹草和菰的基质质量对枯落物质量残余的影响发现，全氮含量对枯落物残余量有负效应，纤维素含量则为正效应。但木质素含量对枯落物质量残余作用相反，灰脉薹草木质素含量对残余有负效应，菰木质素含量则是正效应，进一步解释了不同植物基质质量对分解过程的影响机制的差异。本研究揭示了管理措施、环境因素及不同植物基质质量对草本沼泽湿地枯落物分解的综合影响，为湿地生态系统的可持续管理和恢复提供了科学依据。

        The decomposition of litter is a crucial biogeochemical process in herbaceous marsh wetland ecosystems, and grazing is a primary way human activities influence wetland environments. Therefore, studying the effects of grazing on litter decomposition characteristics is vital for understanding the material cycling and energy flow in wetland ecosystems. This study focuses on the herbaceous marsh wetlands in the lower Tumen River in eastern Jilin Province, China, analyzing how different grazing management practices (natural grazing exclusion, grazing, and fenced grazing exclusion) affect the decomposition characteristics of representative plants from the wetland's major functional groups, specifically Carex grayana from the Cyperaceae family and Zizania latifolia from the Poaceae family. Additionally, it explores the mechanisms through which soil environmental factors and litter quality influence litter decomposition.

        By comparing natural grazing exclusion, grazed, and fenced grazing exclusion wetlands, this study reveals significant differences in litter decomposition rates and nutrient release patterns under different management practices. Specifically, the natural grazing exclusion wetlands exhibited a higher litter decomposition rate, highlighting the positive role of natural conditions in the nutrient cycling of ecosystems. In contrast, although grazing initially accelerated litter decomposition, it lagged behind fenced grazing exclusion in the later stages, reflecting the varying effects of wetland management practices on decomposition rates at different stages. A further comparison of the nutrient content between Carex grayana and Zizania latifolia shows that Carex grayana has higher total carbon, total phosphorus, and lignin content, yet a longer decomposition time than Zizania latifolia. This suggests that litter with higher cellulose and lower lignin content tends to decompose more rapidly. Moreover, soil environmental factors such as water level, soil temperature, soil conductivity, and soil nutrients significantly impact the litter decomposition process and residual mass, underscoring the combined effects of wetland management practices and soil environment on litter decomposition.

         Using structural equation modeling, the study found that grazing primarily impacts litter residual mass indirectly by altering soil physicochemical properties. Comparing the effects of substrate quality between Carex grayana and Zizania latifolia on litter residual mass, it was found that total nitrogen content has a negative effect on litter residual mass, while cellulose content has a positive effect. However, the effects of lignin content on litter residual mass differ between the two species: lignin content in Carex grayana has a negative effect on residual mass, while in Zizania latifolia, it has a positive effect. This further explains the differing mechanisms by which substrate quality affects the decomposition process in different plants. This study highlights the combined effects of management practices, environmental factors, and plant substrate quality on litter decomposition in herbaceous marsh wetlands, providing scientific evidence for the sustainable management and restoration of wetland ecosystems.

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