Abstract Monitoring forests undergoing restoration is important to evaluate not only the development of trees, but also the recovery of ecosystem functions. The decomposition of the organic matter is an important ecological process, and nutrient cycling in ecosystems is a good indicator of forest ecosystem functions because it responds to physical, chemical, and biological characteristics of the vegetation and the soil. We hypothesized that both soil fertility and vegetation structure have direct and positive effects on decomposition processes. We used the Tea Bag Index (Keuskamp et al., 2013) to evaluate early decomposition of the organic matter in three land use categories, pasture, riparian forest undergoing restoration, and riparian forest remnant. Each category extended along a gradient of soil nutrients, enabling to jointly evaluate the effects of soil nutrients and vegetation structure on the decomposition process, using structural equations models to also describe the covariance between soil nutrients and vegetation. The decomposition rates (k) were negatively related to vegetation development, possibly due to less light in the forest floor, and less activity of the decomposer community. On the other hand, soil fertility had direct positive effects on k, possibly with higher microbial activity due to higher nutrient availability. The stabilization factor (S) was not influenced by soil nutrients or vegetation structure. However, in the riparian forest remnant plots, S increased with soil base saturation, indicating an interaction between the effects of soil fertility and land use category. Therefore, the decomposition process in this system responded to soil fertility and vegetation structure, but the magnitude of these effects varied with land use. The monitoring of this ecosystem function to evaluate ecosystem recovery should include simultaneously both soil and vegetation variables.

中文翻译：

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热带河岸带土壤肥力和植被结构对有机质早期分解的综合影响

摘要 森林恢复监测不仅对评价树木的发育状况，而且对生态系统功能的恢复情况也很重要。有机质分解是一个重要的生态过程，生态系统中的养分循环响应植被和土壤的物理、化学和生物特性，是森林生态系统功能的良好指标。我们假设土壤肥力和植被结构对分解过程都有直接和积极的影响。我们使用茶袋指数（Keuskamp 等人，2013 年）来评估三个土地利用类别中有机物质的早期分解：牧场、正在恢复的河岸森林和河岸森林残余。每个类别沿着土壤养分的梯度延伸，能够联合评估土壤养分和植被结构对分解过程的影响，使用结构方程模型也描述土壤养分和植被之间的协方差。分解率 (k) 与植被发育呈负相关，可能是由于森林地面的光照较少，分解者群落的活动较少。另一方面，土壤肥力对 k 有直接的积极影响，可能由于更高的养分可用性而具有更高的微生物活性。稳定因子（S）不受土壤养分或植被结构的影响。然而，在河岸林残余地块中，S随着土壤基础饱和度的增加而增加，表明土壤肥力和土地利用类别的影响之间存在相互作用。所以，该系统中的分解过程对土壤肥力和植被结构有反应，但这些影响的程度因土地利用而异。监测该生态系统功能以评估生态系统恢复应同时包括土壤和植被变量。