International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.5, 206-216 http://ecoevopublisher.com/index.php/ijmec 2 09 Research also shows that communities of decomposers with higher diversity help ecosystems maintain functional stability under environmental stress. This is known as "functional redundancy" and the "insurance effect" - different decomposers respond differently to environmental changes. When the functions of certain species decline due to disturbances, other species can take over their functions. This ensures that the decomposition process and nutrient supply are not interrupted (Njoroge et al., 2022). The continuous process of leaf decomposition can also form a thin layer rich in humus on the soil surface, which helps to reduce the direct erosion of the soil by heavy rain, lower soil erosion, and protect the ecosystem from soil degradation caused by disturbance. This is particularly important for maintaining the long-term stability of the ecosystem. In addition, biological disturbances such as the invasion of alien plants are also closely related to the process of leaf decomposition. Invasive plants often change soil nutrient conditions and microbial communities through their fallen leaves to facilitate their own growth (Bruelheide et al., 2018). 3 The Key Driving Mechanism of Leaf Decomposition 3.1 Biological factors: diversity and functional division of decomposers The decomposer community is the direct executor of the leaf decomposition process, and its composition and function significantly affect the decomposition rate and pathways. Decomposers mainly include two levels: microorganisms (bacteria, fungi, etc.) and soil invertebrates (such as worms, arthropods, etc.). Microorganisms, especially fungi, are the main force in the degradation of complex organic matter such as lignin and cellulose (Purahong et al., 2016). Bacteria play a synergistic role in the decomposition process, especially in the later stage of decomposition. When the substrate becomes relatively simple, bacteria multiply in large numbers and participate in the mineralization of remaining organic substances (such as soluble sugars and amino acids), converting them into inorganic nutrients (Wang et al., 2021). In addition to microorganisms, soil animals (also known as disintegrators) further accelerate the decomposition process through mechanical crushing and ingestion. Another key aspect of biological factors is the diversity of decomposers: an increase in diversity often leads to functional complementarity and redundancy, thereby enhancing the overall decomposition efficiency. Different types of decomposers are adept at breaking down organic matter of various components or playing different roles in the decomposition chain. For instance, some fungi are good at initially invading and decomposing easily decomposable components, while others can degrade lignin that is resistant to decomposition, etc. Among soil animals, some feed on dead leaf fragments, while others prey on microbial communities, influencing microbial activity through trophic level relationships. This functional division of labor and collaboration make the decomposition process more comprehensive and efficient (Liu et al., 2020). 3.2 Abiotic factors: physical and chemical regulation of environmental conditions Environmental conditions are external driving factors that affect the rate and path of leaf decomposition, among which temperature and moisture are the two most important variables (Wu et al., 2025). Temperature directly affects the decomposition process by regulating the metabolic rate of decomposing microorganisms: generally speaking, within a certain range, for every 10℃ increase in temperature, the decomposition rate approximately doubles (i.e., the Q10 effect), because the enzymatic reactions and reproduction rates of microorganisms significantly accelerate at higher temperatures (Zhao et al., 2020). Adequate moisture (moist soil and litter) can promote the growth of microorganisms and increase the rate of enzyme diffusion. The activities of soil animals also become more frequent, thereby accelerating the decomposition process. Conversely, overly dry conditions can cause microorganisms to stagnate and enter dormancy, reduce the activities of soil animals, and limit decomposition (Xi et al., 2024). In addition to temperature and humidity, the physical and chemical properties of the soil among abiotic factors also play a role. For instance, soil pH can affect the composition of microbial communities and the activity of enzymes: a neutral and slightly acidic environment is usually most favorable for most decomposers, including bacteria and fungi, while overly acidic or overly alkaline conditions can reduce decomposition efficiency (Tie et al., 2023).
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