干扰对森林凋落物分解影响的研究现状及展望

Status and Prospect of the Studies of Disturbance Effects on Litter Decomposition in Forest Ecosystems

凋落物分解是森林生态系统物质循环和能量流动的核心环节。干扰能够影响凋落物分解速率和养分循环,进而改变森林生态系统的结构、功能及过程。文章通过整理干扰对森林凋落物分解影响的研究成果,从凋落物质与量、微环境及分解者类群等方面阐述了干扰对森林凋落物分解的影响机制,并分析现有研究的不足,为未来合理经营森林,增加适度干扰提供一定的理论依据。现有的研究表明,间伐等干扰会显著减少森林凋落物产量,改变凋落物化学特性并促进凋落物分解;干扰对凋落物分解环境的影响主要表现于对温湿度的调节,间伐能增加林内贯穿雨量,从而对湿度有显著提升作用;干扰对土壤动物的短期负面影响较为显著,而对微生物种类和数量则显著提高,从而有效地促进凋落物的分解,这主要归因于干扰改变了微环境与凋落物底物的质量;干扰通过改变土壤条件进而影响相关微生物分解酶的活性,酶活性越高,分解越迅速。干扰对林分结构、分解环境等影响因素的改变与凋落物分解之间的关系错综复杂,其中的机制与机理仍有待明晰;不同方式及程度干扰对森林恢复过程中凋落物分解模式的研究尚有待加深;建立干扰梯度以研究森林地上部分对地下部分的调控及反馈应受到重视;如何进行合理的森林经营以促进凋落物分解也需进一步研究。

Litter decomposition is the key process of nutrient cycle and energy flow in forest ecosystems. Disturbances can affect the rate of litter decomposition and nutrient cycling, and consequently alter the structure, functions, and processes of forest ecosystems. In this paper, we summarized the impacts of disturbances on litter decomposition and concluded the mechanisms from the effects on litter quantity and quality, microenvironment and decomposer groups. We also analyzed the deficiency of current research situations and aimed at providing some theoretical basis and direction for the reasonable disturbance of forest management in the future. At present, the studies of the effects of disturbances（such as thinning） can significantly reduce the litter production, and effectively change the chemical characteristics of litter and promote decomposition. The effects of disturbance on the microenvironment are also mainly reflected in the regulation of temperature and humidity, and increase throughfall with thinning, significantly increased the humidity. The short-term negative impacts of soil disturbance are significant. But the significant increase of species and quantity of microorganisms can effectively promote the litter decomposition, which is mainly due to the disturbance that changes the microenvironment and litter quality. On the other hand, disturbances affect the activity of decomposition-related microbial enzymes by changing soil conditions, thereby changing the litter decomposition. However, the complex interactions between disturbance and change of influencing factors such as stand structure, decomposition environment, and litter decomposition are complicated, and the mechanisms remain little understood. The research on litter decomposition model in the process of forest restoration needs to be further studied with different ways and intensities of disruption. More attention should be paid to the regulation and feedback between underground and aboveground when establishing different disturbance gradients and how to carry out reasonable forest management to promote litter decomposition needs further study.