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Molecular Soil Biology (online), 2024, Vol. 15 ISSN 1925-2005 https://bioscipublisher.com/index.php/msb © 2024 BioSci Publisher, an online publishing platform of Sophia Publishing Group. All Rights Reserved. Sophia Publishing Group (SPG), founded in British Columbia of Canada, is a multilingual publisher Latest Content The Role of Leaf Litter in Forest Soil Fertility and Microbial Diversity Kaiwen Liang Molecular Soil Biology, 2024, Vol. 15, No. 11 Snow Cover Dynamics: Impacts on Soil Moisture and Plant Growth in Temperate Ecosystems Siyue Cai, Qiongdan Li Molecular Soil Biology, 2024, Vol. 15, No. 12 Pesticide Usage in Rice Cultivation: Consequences for Soil and Water Health Ruchun Chen, Qifu Zhang Molecular Soil Biology, 2024, Vol. 15, No. 13 Boosting Soil Health: The Role of Rhizobium in Legume Nitrogen Fixation Wenzhong Huang Molecular Soil Biology, 2024, Vol. 15, No. 14 Impact of Soil Insecticides on Western Corn Rootworm and Maize Yield Shanjun Zhu, Wei Wang Molecular Soil Biology, 2024, Vol. 15, No. 15
Molecular Soil Biology 2024, Vol.15, No.3, 99-108 http://bioscipublisher.com/index.php/msb 99 Review Article Open Access The Role of Leaf Litter in Forest Soil Fertility and Microbial Diversity Kaiwen Liang Agri-Products Application Center, Hainan Institute of Tropical Agricultural Resouces, Sanya, 572025, Hainan, China Corresponding email: kaiwen.liang@hitar.org Molecular Soil Biology, 2024, Vol.15, No.3 doi: 10.5376/msb.2024.15.0011 Received: 13 Mar., 2024 Accepted: 18 Apr., 2024 Published: 07 May, 2024 Copyright © 2024 Liang, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Liang K.W., 2024, The role of leaf litter in forest soil fertility and microbial diversity, Molecular Soil Biology, 15(3): 99-108 (doi: 10.5376/msb.2024.15.0011) Abstract Leaf litter plays a crucial role in forest ecosystems by contributing to soil fertility and enhancing microbial diversity. This study examines the multifaceted impact of leaf litter on forest soil fertility and microbial communities. The decomposition of leaf litter, primarily driven by microbial activity, is essential for nutrient cycling and maintaining soil health. Fungi and bacteria are the primary decomposers, with fungi often being the dominant agents due to their enzymatic capabilities and substrate accessibility. The diversity and composition of leaf litter significantly influence microbial activity and nutrient cycling, with mixed-species litter often promoting higher microbial diversity and decomposition rates compared to monocultures. Environmental factors such as temperature, moisture, and soil pH also play critical roles in shaping microbial communities and their functions. Additionally, the identity and quality of leaf litter, including its chemical composition, affect microbial biomass and the abundance of soil organisms. This study highlights the complex interactions between leaf litter, microbial communities, and environmental conditions, emphasizing the importance of maintaining litter diversity for ecosystem health and resilience. Keywords Leaf litter; Soil fertility; Microbial diversity; Nutrient cycling; Decomposition 1 Introduction Forest ecosystems are among the most productive and complex biomes on Earth, playing a crucial role in global carbon cycling and serving as significant carbon sinks (Baldrian, 2016; Lladó et al., 2017). These ecosystems are characterized by a high level of spatial heterogeneity and dynamic processes that range from short-term events to long-term ecological developments. The primary producers in these ecosystems, mainly trees, contribute to the structure and functioning of forests by providing habitats and resources for a diverse array of organisms, including fungi, bacteria, and archaea (Baldrian, 2016). The intricate interactions among these organisms and their environment are essential for maintaining ecosystem health and resilience, particularly in the face of global changes such as climate warming and increased carbon dioxide levels (Lladó et al., 2017). Leaf litter, the layer of fallen leaves and other organic material on the forest floor, is a critical component of forest ecosystems. It plays a dual role in nutrient and carbon cycling and in regulating microclimatic conditions (Sayer, 2005). The decomposition of leaf litter is a key process in biogeochemical cycles, driven primarily by microbial communities, including fungi and bacteria (Baldrian, 2017; Bani et al., 2018). Fungi are particularly important due to their ability to produce specific enzymes that break down complex plant biomass, while bacteria contribute significantly to the decomposition of fungal mycelia and nitrogen cycling processes (Baldrian, 2017). The quality and quantity of leaf litter can influence microbial community composition and activity, thereby affecting soil fertility and ecosystem functioning (Bani et al., 2018; Feng et al., 2022). This study aims to synthesize current knowledge on the role of leaf litter in forest soil fertility and microbial diversity. Specifically, it will examine the processes of leaf litter decomposition and its impact on nutrient cycling and soil organic carbon pools. Explore the interactions between leaf litter and microbial communities, including the effects of litter diversity on microbial activity and community structure. Assess the influence of environmental factors, such as climate and soil properties, on the decomposition process and microbial dynamics. And identify gaps in the current understanding and suggest directions for future research to enhance our knowledge of leaf litter's role in forest ecosystems. By integrating findings from various studies, this study will provide a comprehensive understanding of how leaf litter contributes to forest soil fertility and microbial diversity, highlighting its importance in maintaining ecosystem health and resilience.
Molecular Soil Biology 2024, Vol.15, No.3, 99-108 http://bioscipublisher.com/index.php/msb 100 2 Composition and Decomposition of Leaf Litter 2.1 Chemical composition of leaf litter Leaf litter is composed of various chemical constituents, including lignin, cellulose, hemicellulose, tannins, and nutrients such as nitrogen (N), phosphorus (P), and calcium (Ca). These components play crucial roles in determining the decomposition rate and nutrient cycling within forest ecosystems. For instance, cellulose is a dominant polysaccharide in plant litter and significantly influences the decomposition process due to its abundance and the specific microbial communities it attracts (Štursová et al., 2012). Lignin, another major component, is more resistant to decomposition and requires specialized enzymes produced primarily by fungi (Bani et al., 2018). The nutrient content, such as N and P, also affects the microbial activity and decomposition rates, with higher nutrient levels generally promoting faster decomposition (Luo et al., 2017). 2.2 Decomposition processes and factors influencing decomposition rates The decomposition of leaf litter is a complex process influenced by both abiotic and biotic factors. This process is essential for nutrient cycling and maintaining soil fertility in forest ecosystems. 2.2.1 Abiotic factors (temperature, moisture) Temperature and moisture are critical abiotic factors that significantly influence the decomposition rates of leaf litter. Higher temperatures generally accelerate microbial activity, leading to faster decomposition rates. Moisture availability is equally important, as it affects the microbial community structure and their enzymatic activities. For example, in a study on macrophyte leaf litter, it was found that decomposition rates varied significantly with temperature, with higher rates observed at elevated temperatures (Zhao et al., 2020). Similarly, soil moisture levels can impact the microbial community composition and activity, thereby influencing the decomposition process (Dong et al., 2021). 2.2.2 Biotic factors (microbial activity, fauna) Microbial communities, including bacteria and fungi, are the primary agents of leaf litter decomposition. Fungi, in particular, play a dominant role due to their ability to produce specific enzymes that break down complex organic compounds like lignin and cellulose (Bani et al., 2018). Bacteria also contribute significantly, especially in the later stages of decomposition when simpler compounds are more prevalent (Štursová et al., 2012). Soil fauna, such as earthworms and insects, also play a crucial role by physically breaking down litter and enhancing microbial access to organic matter. A meta-analysis revealed that soil fauna could contribute up to 30.9% to the forest litter decomposition rate, with their impact being more pronounced in warmer and moister climates (Xu et al., 2020). 2.3 Role of leaf litter in nutrient cycling Leaf litter plays a pivotal role in nutrient cycling within forest ecosystems. As litter decomposes, it releases essential nutrients back into the soil, which are then available for plant uptake. This process is crucial for maintaining soil fertility and supporting plant growth. The decomposition of leaf litter contributes to the formation of soil organic matter (SOM), which is vital for soil structure and nutrient retention (Prescott and Vesterdal, 2021). The nutrient content of the litter, such as N and P, influences the rate of nutrient release and the overall nutrient dynamics in the soil. For instance, mixed leaf litter has been shown to enhance microbial diversity and nutrient release compared to single-species litter, thereby promoting more efficient nutrient cycling (Liu et al., 2022). 3 Impact of Leaf Litter on Soil Fertility 3.1 Contribution of decomposed leaf litter to soil organic matter Decomposed leaf litter plays a crucial role in contributing to soil organic matter (SOM). The decomposition process, primarily driven by microbial communities, breaks down complex organic compounds in leaf litter into simpler forms, which are then incorporated into the soil. This process not only enriches the soil with organic carbon but also enhances its overall fertility. For instance, the addition of leaf litter has been shown to increase soil organic carbon mineralization, thereby contributing to the soil's organic matter content (Wang et al., 2014). Furthermore, volatile organic compounds (VOCs) released during leaf litter decomposition can diffuse into the soil matrix, contributing to various soil carbon pools and altering soil microbial communities (McBride et al., 2020).
Molecular Soil Biology 2024, Vol.15, No.3, 99-108 http://bioscipublisher.com/index.php/msb 101 3.2 Nutrient release and availability (nitrogen, phosphorus, potassium) The decomposition of leaf litter is a critical process for the release and availability of essential nutrients such as nitrogen (N), phosphorus (P), and potassium (K). During decomposition, microorganisms, particularly fungi and bacteria, break down the organic matter, releasing these nutrients back into the soil (Figure 1). Studies have shown that the nutrient content and rate of decomposition of mixed litters are significantly different from those of single species, with mixed litters promoting higher microbial diversity and nutrient release (Liu et al., 2022). Additionally, the enrichment of ecosystems by nutrients like N and P has been found to have significant effects on fungal decomposers, which play a pivotal role in nutrient cycling (Jabiol et al., 2018). The addition of leaf litter has also been shown to increase soil microbial biomass carbon and nitrogen, further enhancing nutrient availability (Zhang et al., 2022). Figure 1 The continuum of litter decomposition pathways, showing influence of soil and parent material characteristics on soil biota, litter quality, decomposition pathway, and SOM and humus forms. In natural forests, the dominant tree species reflect these site conditions. Planted trees can shift conditions to some extent (Adopted from Prescott et al., 2021) 3.3 Enhancement of soil structure and water retention Leaf litter decomposition not only contributes to soil fertility but also enhances soil structure and water retention. The organic matter from decomposed leaf litter improves soil aggregation, which in turn enhances soil porosity and water-holding capacity. This is particularly important in maintaining soil health and preventing erosion. The
Molecular Soil Biology 2024, Vol.15, No.3, 99-108 http://bioscipublisher.com/index.php/msb 102 presence of diverse microbial communities during litter decomposition has been linked to improved soil structure and stability (Pei et al., 2017). Moreover, the decomposition process can influence soil microbial community structure, which plays a role in maintaining soil physical properties. The addition of leaf litter has been shown to stimulate soil microbial activity, which can lead to better soil structure and increased water retention (Dong et al., 2021). 4 Influence of Leaf Litter on Microbial Diversity 4.1 Microbial communities in leaf litter (bacteria, fungi, actinomycetes) Leaf litter serves as a critical habitat for diverse microbial communities, including bacteria, fungi, and actinomycetes. Studies have shown that the composition and diversity of these microbial communities are influenced by the type and diversity of leaf litter. For instance, in a Schrenk’s Spruce forest, the dominant bacterial phyla in leaf litter were Proteobacteria, Acidobacteria, and Actinomycetes, while the dominant fungal phyla were Basidiomycota, Ascomycota, and Mortierellomycota (Zhu et al., 2022). Similarly, in a Mediterranean oak forest, bacterial and fungal communities in leaf litter varied significantly during decomposition, with distinct succession patterns observed for each community (Santonja et al., 201). The presence of high-tannin leaf litter from transgenic poplars also influenced microbial communities, with notable changes in the abundance of Actinobacteria and various fungal classes (Winder et al., 2013). 4.2 Interactions between leaf litter and soil microbiota The interactions between leaf litter and soil microbiota are complex and dynamic, significantly affecting soil microbial community structure and function. Leaf litter inputs can alter soil microbial activities and nutrient cycling, as observed in various forest ecosystems. For example, litter and root manipulations in a Schrenk’s Spruce forest led to changes in soil bacterial and fungal communities, with litter removal decreasing the diversity of these communities (Zhu et al., 2022). In a subtropical forest ecosystem, increased leaf litter diversity was positively correlated with the abundance of mycorrhizal fungi and actinomycetes, indicating strong interactions between aboveground litter and belowground microbial communities (Pei et al., 2017). Additionally, the composition of microbial communities in litter and soil is influenced by tree species, with distinct microbial communities developing on decomposing leaf litters of different tree species (Prescott and Grayston, 2013). 4.3 Impact of leaf litter on microbial diversity and abundance Leaf litter has a profound impact on microbial diversity and abundance in forest soils. The diversity of leaf litter inputs can lead to cascading effects on microbial communities. In a Mediterranean oak forest, increased litter species diversity was associated with higher fungal diversity but lower bacterial diversity, highlighting the differential impact of litter diversity on microbial communities (Santonja et al., 2018). In a mixed Quercus acutissima and Robinia pseudoacacia forest, the decomposition rate of litter and the stability of microbial alpha diversity were higher compared to a pure Quercus acutissima forest, suggesting that mixed forests support more stable microbial communities (Dong et al., 2021). Furthermore, changes in litter input, such as litter removal or addition, can significantly affect soil microbial biomass and enzyme activity, with varying effects depending on forest stand density and soil quality (Wang et al., 2022). Overall, leaf litter plays a crucial role in shaping the diversity and abundance of microbial communities in forest soils, thereby influencing ecosystem functions such as nutrient cycling and decomposition. 5 Leaf Litter and Soil Health 5.1 Indicators of soil health influenced by leaf litter Leaf litter plays a crucial role in influencing various indicators of soil health, including soil physicochemical properties, microbial biomass, and nutrient cycling. The addition of leaf litter from different tree species significantly affects soil total nitrogen, available NPK, and soil microbial biomass, which are critical indicators of soil health (Sun et al., 2017). For instance, the decomposition of mixed coniferous and broadleaf litters has been shown to enhance the carbon metabolic intensity, richness, and diversity of soil microbial communities, thereby improving soil health (Naimei, 2011). Additionally, the quality and quantity of leaf litter can influence the rate of litter decomposition and nutrient release, which are essential for maintaining soil fertility and microbial diversity (Silva et al., 2018).
Molecular Soil Biology 2024, Vol.15, No.3, 99-108 http://bioscipublisher.com/index.php/msb 103 The microbial community structure is also a vital indicator of soil health influenced by leaf litter. Studies have shown that the addition of leaf litter can alter the composition and functional characteristics of soil microbial communities. For example, the decomposition of leaf litter from dominant tree species enhances the metabolic capacity and functional diversity of soil microbes, which is crucial for soil health and forest succession (Liang et al., 2015). Moreover, the presence of specific microbial taxa, such as nitrifying and nitrogen-fixing bacteria, can be indicative of the nutrient status and overall health of the soil (Tanikawa et al., 2022). 5.2 Role in disease suppression and plant health Leaf litter not only contributes to soil health but also plays a significant role in disease suppression and plant health. The decomposition of leaf litter can lead to the release of various organic compounds and nutrients that enhance soil microbial activity and diversity, which in turn can suppress soil-borne pathogens. For instance, the addition of leaf litter has been shown to increase the ATP-to-microbial biomass C ratio and the ergosterol-to-microbial biomass C ratio, indicating a more active and diverse microbial community capable of outcompeting pathogenic organisms (Salamanca et al., 2006). Furthermore, the presence of a diverse microbial community in the soil, fostered by leaf litter decomposition, can enhance plant health by promoting beneficial symbiotic relationships and improving nutrient availability. The increased microbial diversity and activity can lead to better nutrient cycling and availability, which supports plant growth and resilience against diseases (Dong et al., 2021). Additionally, the specific composition of leaf litter, such as the carbon-to-nitrogen ratio and lignin content, can influence the microbial community structure and its ability to suppress plant pathogens (Naimei, 2011). In summary, leaf litter significantly influences soil health indicators and plays a vital role in disease suppression and plant health by enhancing soil microbial diversity and activity. The decomposition of leaf litter from various tree species contributes to nutrient cycling, improves soil physicochemical properties, and fosters a diverse microbial community that supports healthy plant growth and resilience against diseases (Liang et al., 2015; Dong et al., 2021). 6 Case Studies 6.1 Effects of leaf litter on soil fertility in temperate forests Leaf litter plays a crucial role in maintaining soil fertility in temperate forests. The decomposition of leaf litter releases essential nutrients back into the soil, which are vital for plant growth. For instance, the leachates from broadleaf litter in temperate forests contain higher amounts of carbon and nitrogen, which significantly enhance soil microbial activity and respiration, leading to improved soil fertility (Joly et al., 2016). Additionally, the diversity of leaf litter can influence the microbial community structure and nutrient cycling, as observed in mixed Quercus acutissima and Robinia pseudoacacia forests in Northern China, where mixed forests showed more stable microbial diversity and better nutrient cycling compared to pure forests (Dong et al., 2021). 6.2 Leaf litter's role in microbial diversity in tropical rainforests In tropical rainforests, leaf litter significantly impacts microbial diversity and function. The identity of leaf litter species, rather than their diversity, has been shown to shape microbial functions and the abundance of soil organisms. For example, in Ecuadorian tropical montane rainforests, leaf litter from species with low carbon-to-nitrogen ratios, such as Cecropia andina, improved microbial activity and increased the abundance of microarthropods (Sánchez-Galindo et al., 2021). Furthermore, the addition of different leaf litter types to tropical forest soils in the Philippines altered soil microbial biomass and energy charge, indicating that leaf litter quality directly influences microbial community dynamics (Salamanca et al., 2006). 6.3 Leaf litter's impact on soil health in boreal forests In boreal forests, leaf litter contributes to soil health by influencing microbial community structure and nutrient availability. The decomposition of leaf litter and deadwood is primarily driven by fungi, which play a significant role in nutrient cycling and maintaining soil health (Bani et al., 2018). However, the impact of leaf litter on microbial biomass and community structure can vary. For instance, a global meta-analysis revealed that
Molecular Soil Biology 2024, Vol.15, No.3, 99-108 http://bioscipublisher.com/index.php/msb 104 aboveground litter removal decreased soil microbial biomass and altered the fungi-to-bacteria ratio, highlighting the importance of leaf litter in maintaining microbial balance and soil health in forest ecosystems (Jing et al., 2021). 6.4 Best practices for leaf litter management in mixed forests Effective leaf litter management in mixed forests involves maintaining a balance between litter diversity and quality to support soil microbial communities and nutrient cycling. Studies have shown that mixed-species leaf litter can lead to non-additive effects on soil microbial activity, suggesting that the combination of different litter types can provide complementary resources for microorganisms (Joly et al., 2016). In subtropical forests, higher litter species diversity was associated with increased microbial biomass and enzyme activity, indicating that diverse litter inputs can enhance soil health and ecosystem functions (Pei et al., 2017). Therefore, promoting mixed-species forests and managing leaf litter to ensure a variety of litter types can be beneficial for maintaining soil fertility and microbial diversity. 7 Management Practices for Enhancing Leaf Litter Benefits 7.1 Sustainable forest management practices Sustainable forest management practices are essential for maintaining the ecological balance and enhancing the benefits of leaf litter in forest ecosystems. One of the key practices involves the strategic management of both aboveground and belowground litter inputs. Research indicates that root litter inputs exert a larger control on microbial biomass than aboveground litter inputs, suggesting that forest management should consider the balance between these two types of litter to optimize soil microbial communities and carbon stability (Jing et al., 2021). Additionally, the decomposition of leaf litter and deadwood plays a crucial role in nutrient cycling and soil fertility, with fungi being major contributors due to their enzymatic capabilities (Bani et al., 2018). Therefore, promoting the growth of diverse fungal communities through sustainable practices can enhance the decomposition process and improve soil health. Another important aspect is the management of litter diversity and identity. Studies have shown that leaf litter identity significantly influences microbial functions and microarthropod abundance, with high-quality species (low C-to-N ratio) improving resource quality and microbial activity (Sánchez-Galindo et al., 2021). This highlights the importance of maintaining a diverse range of tree species in forests to ensure a balanced and effective decomposition process. Moreover, the use of mixed litters, such as coniferous and broadleaf combinations, has been found to increase the carbon metabolic function of soil microbial communities, further supporting the need for diverse litter inputs (Naimei, 2011). 7.2 Leaf litter management in forestry and agriculture In forestry and agriculture, effective leaf litter management can significantly enhance soil fertility and microbial diversity. One approach is the use of vermicomposting, which involves the recycling of nutrients from leaf litter waste using earthworms like Eisenia fetida. This method has been shown to improve soil physicochemical properties and increase microbial populations, making it a valuable practice for sustainable soil fertility management (Suthar and Gairola, 2014). Additionally, the incorporation of different leaf litters into soil can alter soil properties and enhance microbial community functions. For instance, the addition of leaf litters from various tree species to Panax ginseng-growing soil significantly affected soil nitrogen, phosphorus, and potassium levels, as well as microbial biomass (Sun et al., 2017). Furthermore, the use of leaf litter extraction fluids from dominant tree species can enhance the metabolic capacity and functional diversity of soil microbes, contributing to forest succession and soil quality improvement (Liang et al., 2015). This practice can be particularly useful in abandoned lands or areas undergoing reforestation, where enhancing soil microbial activity is crucial for ecosystem recovery. 8 Challenges and Future Directions 8.1 Challenges in studying leaf litter decomposition and its effects Studying leaf litter decomposition in forest ecosystems presents several challenges. One significant challenge is the complexity of interactions between microbial communities and environmental variables such as temperature
Molecular Soil Biology 2024, Vol.15, No.3, 99-108 http://bioscipublisher.com/index.php/msb 105 and moisture, which can influence decomposition rates and nutrient cycling (Bani et al., 2018). Additionally, the variability in litter quality, including differences in chemical composition and physical structure, further complicates the study of decomposition processes (Elias et al., 2020; Sánchez-Galindo et al., 2021). The presence of diverse microbial communities, including fungi and bacteria, and their succession over time adds another layer of complexity, making it difficult to isolate specific factors that drive decomposition (He et al., 2016; Bani et al., 2018). Moreover, the effects of forest management practices, such as logging and the creation of forest gaps, on litter decomposition and soil fauna diversity are context-dependent and require long-term studies to fully understand (Huang et al., 2020; Dong et al., 2021). 8.2 Knowledge gaps and research needs Despite significant progress in understanding leaf litter decomposition, several knowledge gaps remain. One major gap is the limited understanding of the role of bacteria in decomposition, which has historically been overshadowed by the focus on fungi (Bani et al., 2018). Additionally, the interactions between microbial community composition, litter chemistry, and decomposition rates are not fully understood, particularly in different forest types and under varying environmental conditions (He et al., 2016; Luo et al., 2017). There is also a need for more research on the effects of litter diversity versus litter identity on microbial functions and soil fauna abundance, as current studies provide mixed results (Santonja et al., 2017; Sánchez-Galindo et al., 2021). Furthermore, the impact of climate change, particularly increased drought, on litter decomposition and soil biota requires further investigation to predict future ecosystem responses (Santonja et al., 2017). 8.3 Future prospects for leaf litter research in forest ecosystems Future research on leaf litter decomposition should focus on several key areas. First, there is a need for more comprehensive studies that integrate the roles of both fungi and bacteria in decomposition processes, considering their interactions and contributions to nutrient cycling (Luo et al., 2017; Bani et al., 2018). Long-term experiments that manipulate environmental variables, such as temperature and moisture, will help elucidate the effects of climate change on decomposition rates and microbial community dynamics (Santonja et al., 2017). Additionally, studies should explore the effects of different forest management practices, including the creation of forest gaps and mixed-species plantations, on litter decomposition and soil biodiversity (Huang et al., 2020; Dong et al., 2021). Advances in molecular techniques, such as metatranscriptomics, can provide deeper insights into the diversity and functional roles of protists and other microorganisms in leaf litter (Voß et al., 2019). Finally, research should aim to develop predictive models that incorporate microbial community composition, litter quality, and environmental factors to better understand and manage forest ecosystems in the face of global change (He et al., 2016; Luo et al., 2017). 9 Concluding Remarks The role of leaf litter in forest soil fertility and microbial diversity is multifaceted and significant. Research indicates that both the diversity and identity of leaf litter influence microbial functions and soil properties. For instance, leaf litter diversity can enhance microbial activity and nutrient cycling, although the specific effects can vary over time and with different litter compositions. High-quality leaf litter, characterized by a low carbon-to-nitrogen ratio, tends to improve resource quality and increase the abundance of soil microarthropods. Additionally, the chemical composition of leaf litter leachates significantly affects soil microbial activity, with broadleaf litter generally providing more labile carbon and nutrients compared to coniferous litter. The diversity of microbial communities in the litter layer is also influenced by the diversity and identity of the leaf litter, with distinct succession patterns observed for bacterial and fungal communities. The findings underscore the importance of maintaining tree species diversity in forest ecosystems to support soil fertility and microbial diversity. Forest management practices should consider the composition and diversity of leaf litter to promote healthy soil microbial communities and efficient nutrient cycling. For example, incorporating a mix of high-quality leaf litter species can enhance microbial activity and improve soil health. Additionally, understanding the specific effects of different tree species on soil properties can inform reforestation and conservation strategies, ensuring that the selected species contribute positively to soil microbial diversity and
Molecular Soil Biology 2024, Vol.15, No.3, 99-108 http://bioscipublisher.com/index.php/msb 106 ecosystem functions. The role of leaf litter in shaping soil microbial communities also highlights the need for preserving native tree species and preventing the loss of biodiversity, which could have cascading effects on soil health and forest ecosystem stability. Leaf litter plays a crucial role in forest ecosystems by influencing soil fertility, microbial diversity, and nutrient cycling. The interactions between leaf litter and soil microorganisms are complex and driven by both the diversity and identity of the litter. These interactions are essential for maintaining the health and productivity of forest soils. As such, leaf litter should be recognized as a vital component of forest ecosystems, with significant implications for forest management and conservation efforts. By fostering diverse and high-quality leaf litter inputs, we can support robust soil microbial communities and ensure the long-term sustainability of forest ecosystems. Acknowledgments The author sincerely appreciates the valuable opinions and suggestions provided by the three anonymous reviewers, whose meticulous review greatly helped us improve the quality of this article. Conflict of Interest Disclosure The author affirms that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest. References Baldrian P., 2016, Forest microbiome: diversity, complexity and dynamics, FEMS microbiology reviews, 41(2): 109-130. https://doi.org/10.1093/femsre/fuw040 Baldrian P., 2017, Microbial activity and the dynamics of ecosystem processes in forest soils, Current opinion in microbiology, 37: 128-134. https://doi.org/10.1016/j.mib.2017.06.008 Bani A., Pioli S., Ventura M., Panzacchi P., Borruso L., Tognetti R., Tonon G., and Brusetti L., 2018, The role of microbial community in the decomposition of leaf litter and deadwood, Applied Soil Ecology, 126: 75-84. https://doi.org/10.1016/J.APSOIL.2018.02.017 Dong X., Gao P., Zhou R., Li C., Dun X., and Niu X., 2021, Changing characteristics and influencing factors of the soil microbial community during litter decomposition in a mixed Quercus acutissima Carruth. and Robinia pseudoacacia L. forest in Northern China, Catena, 196: 104811. https://doi.org/10.1016/j.catena.2020.104811 Elias D., Robinson S., Both S., Goodall T., Majalap-Lee N., Ostle N., and McNamara N., 2020, Soil microbial community and litter quality controls on decomposition across a tropical forest disturbance gradient, Front. For. Glob. Change, 3: 81. https://doi.org/10.3389/ffgc.2020.00081 Feng J., He K., Zhang Q., Han M., and Zhu B., 2022, Changes in plant inputs alter soil carbon and microbial communities in forest ecosystems, Global Change Biology, 28: 3426-3440. https://doi.org/10.1111/gcb.16107 He Z., Yu Z., Huang Z., Davis M., and Yang Y., 2016, Litter decomposition, residue chemistry and microbial community structure under two subtropical forest plantations: A reciprocal litter transplant study, Applied Soil Ecology, 101: 84-92. https://doi.org/10.1016/J.APSOIL.2016.01.015 Huang Y., Yang X., Zhang D., and Zhang J., 2020, The effects of gap size and litter species on colonization of soil fauna during litter decomposition in Pinus massoniana plantations, Applied Soil Ecology, 155: 103611. https://doi.org/10.1016/j.apsoil.2020.103611 Jabiol J., Cornut J., Tlili A., and Gessner M., 2018, Interactive effects of dissolved nitrogen, phosphorus and litter chemistry on stream fungal decomposers, FEMS microbiology ecology, 94: 10. https://doi.org/10.1093/femsec/fiy151 Jing Y., Tian P., Wang Q., Li W., Sun Z., and Yang H., 2021, Effects of root dominate over aboveground litter on soil microbial biomass in global forest ecosystems, Forest Ecosystems, 8: 1-9. https://doi.org/10.1186/s40663-021-00318-8 Joly F., Fromin N., Kiikkila O., and Hattenschwiler S., 2016, Diversity of leaf litter leachates from temperate forest trees and its consequences for soil microbial activity, Biogeochemistry, 129: 373-388. https://doi.org/10.1007/s10533-016-0239-z Liang J., Lu Z., Yu Z., Wang J., and Wang X., 2015, Effects of leaf litter extraction fluid from dominant forest tree species on functional characteristics of soil microbial communities, Journal of Forestry Research, 27: 81-90. https://doi.org/10.1007/s11676-015-0138-5
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Molecular Soil Biology 2024, Vol.15, No.3, 109-117 http://bioscipublisher.com/index.php/msb 109 Systematic Review Open Access Snow Cover Dynamics: Impacts on Soil Moisture and Plant Growth in Temperate Ecosystems Siyue Cai, Qiongdan Li Biotechnology Research Center, Cuixi Academy of Biotechnology, Zhuji, 311800, China Corresponding email: qiongdan.li@cuixi.org Molecular Soil Biology, 2024, Vol.15, No.3 doi: 10.5376/msb.2024.15.0012 Received: 17 Mar., 2024 Accepted: 29 Apr., 2024 Published: 14 May, 2024 Copyright © 2024 Cai and Li, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Cai S.Y., and Li Q.D., 2024, Snow cover dynamics: impacts on soil moisture and plant growth in temperate ecosystems, Molecular Soil Biology, 15(3): 109-117 (doi: 10.5376/msb.2024.15.0012) Abstract Snow cover is a crucial natural phenomenon in temperate ecosystems, significantly influencing soil moisture regulation and plant growth cycles. With the intensification of global climate change, the seasonal patterns and distribution of snow cover are undergoing shifts that may have substantial long-term effects on ecosystem functionality and biodiversity. This study delves into the complex dynamics of snow cover, examining its seasonal variations and the multifaceted impacts of factors such as climate change and geographical differences. At its core, this research explores how snow cover aids in soil moisture retention, facilitates water infiltration through snowmelt mechanisms, and affects soil temperature regimes, thereby influencing plant dormancy and germination cycles. Through comprehensive analysis of case studies across different temperate regions and comparative assessments across various temperate zones, this study aims to highlight the critical role of snow in maintaining ecosystem functions and to inform future research directions and conservation practices. Keywords Snow cover; Soil moisture; Plant growth; Climate change; Temperate ecosystems 1 Introduction Snow cover plays a crucial role in temperate ecosystems, influencing a wide range of ecological and environmental processes. The accumulation and melting of snow determine ground temperature, light conditions, and moisture availability during winter, which in turn affect the timing of the growing season and the availability of nutrients for plants (Rixen et al., 2022). Snow cover dynamics are driven by various factors, including atmospheric conditions, wind-driven processes, and topographical features, which contribute to the spatial and temporal variability of snow accumulation and melt (Mott et al., 2018). Understanding these dynamics is essential for predicting the impacts of changing snow regimes on ecosystems. In temperate ecosystems, snow cover acts as an insulating layer that protects soil and plant roots from extreme cold, thereby maintaining soil microbial activity and nutrient cycling during winter (Rumpf et al., 2014). The depth and duration of snow cover influence soil moisture levels, which are critical for plant growth and productivity in the subsequent growing season (Wang et al., 2018; Moriana-Armendariz et al., 2022). Changes in snow cover can lead to shifts in vegetation composition, plant phenology, and soil nutrient status, with cascading effects on the entire ecosystem. For instance, reduced snow depth often results in increased plant mortality and physical injury, while earlier snowmelt can advance spring phenology in plants and other organisms (Slatyer et al., 2020; Slatyer et al., 2021). This study aims to synthesize the current knowledge on the effects of snow cover dynamics on soil moisture and plant growth in temperate ecosystems. Specifically, to study how changes in snow cover depth and melting time affect soil moisture levels and nutrient availability; Identify the mechanisms behind these responses and their impact on ecosystem functioning. By integrating the results of multiple studies, it is beneficial to fully understand the role of snow cover in temperate ecosystems and highlight research gaps that need to be addressed to improve the prediction of ecosystem responses to future climate change.
Molecular Soil Biology 2024, Vol.15, No.3, 109-117 http://bioscipublisher.com/index.php/msb 110 2 Snow Cover Dynamics 2.1 Definition and characteristics of snow cover Snow cover refers to the layer of snow that accumulates on the ground surface during winter. It plays a crucial role in the climate system by influencing ground temperature, light conditions, and moisture availability. Snow cover acts as an insulating layer, protecting the soil and vegetation from extreme cold temperatures and maintaining soil moisture levels by reducing evaporation (Oppen et al., 2022). The characteristics of snow cover, such as depth and duration, are essential in determining its impact on the ecosystem. For instance, deeper snow cover can enhance soil moisture and stabilize plant community composition by providing a consistent water source during the early growing season (Li et al., 2020). 2.2 Seasonal variations in snow cover Seasonal variations in snow cover are primarily driven by changes in temperature and precipitation patterns. During winter, snow accumulates and forms a protective layer over the soil and vegetation. As temperatures rise in spring, snow begins to melt, releasing stored water into the soil, which is crucial for the onset of the growing season (Chen et al., 2019). The timing of snowmelt can significantly influence plant phenology, with earlier snowmelt advancing the start of the growing season and potentially exposing plants to frost damage (Sanders and Templer, 2017). In contrast, delayed snowmelt can extend the period of soil moisture availability, benefiting plant growth and carbon uptake. 2.3 Factors influencing snow cover dynamics (e.g., climate change, geographical location) Several factors influence snow cover dynamics, including climate change, geographical location, and local environmental conditions. Climate change is a significant driver, leading to alterations in snowfall patterns, snow depth, and the timing of snowmelt. Rising global temperatures are causing a shift from snow to rain in many regions, reducing snow cover duration and depth (Wipf et al., 2009; Slatyer et al., 2021). Geographical location also plays a crucial role, with high-latitude and high-altitude regions experiencing more pronounced changes in snow cover due to their sensitivity to temperature fluctuations (Wang et al., 2018). Additionally, local factors such as vegetation type, topography, and soil moisture can modulate the effects of snow cover on the ecosystem. For example, in temperate China, thicker snow cover and later snowmelt generally enhance soil moisture and lengthen the growing season, promoting higher carbon uptake (Chen et al., 2019). Conversely, in alpine tundra ecosystems, reduced snow depth and earlier snowmelt can lead to increased plant mortality and altered species composition. 3 Impacts on Soil Moisture 3.1 Role of snow cover in soil moisture retention Snow cover plays a crucial role in soil moisture retention by acting as an insulating layer that prevents soil from freezing deeply and maintains higher soil moisture levels during winter. In temperate forests, reduced snow cover due to climate change can lead to increased soil freezing, which in turn affects soil moisture dynamics during the snowmelt period (Blankinship and Hart, 2012). Additionally, in arid grasslands, increased winter snowfall has been shown to enhance soil moisture in the early growing season, particularly in deeper soil layers, which is critical for plant growth and ecosystem stability (Li et al., 2020). 3.2 Mechanisms of snowmelt and water infiltration The process of snowmelt significantly influences water infiltration into the soil. Snowmelt provides a steady supply of water that infiltrates the soil, replenishing soil moisture levels. In northern hardwood forests, snow depth manipulation experiments have demonstrated that reduced snow cover leads to lower soil moisture levels during the snowmelt period, as less snow results in less water available for infiltration (Christiansen et al., 2018). Similarly, in temperate China, thicker snow cover and later snowmelt have been associated with increased soil moisture, which positively impacts vegetation growth by extending the growing season (Chen et al., 2019). 3.3 Effects of snow cover duration and depth on soil moisture levels The duration and depth of snow cover are critical factors that determine soil moisture levels. Longer and deeper snow cover periods generally result in higher soil moisture levels due to prolonged insulation and gradual water
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