Molecular Soil Biology 2024, Vol.15, No.3, 109-117 http://bioscipublisher.com/index.php/msb 112 4.2 Effects on plant dormancy and germination Snow cover plays a crucial role in the dormancy and germination of plants. For cold-temperate tree species, increased snow cover has been shown to enhance post-winter sapling survival by protecting roots from frost heaving. However, the effects on seed germination can vary; some species experience decreased germination rates with increased snow cover, particularly those that disperse seeds in summer or fall (Darrouzet-Nardi et al., 2019). This variability highlights the complex relationship between snow cover and plant reproductive success. 4.3 Impact of snowmelt timing on plant growth cycles The timing of snowmelt is critical for the initiation of plant growth cycles. Earlier snowmelt can advance the start of the growing season, but it may also expose plants to late frost events, which can negate the benefits of a longer growing season. In the Arctic, earlier snowmelt without additional spring warming has been associated with smaller plant sizes, indicating that the timing of snowmelt must coincide with favorable temperature conditions to benefit plant growth (Rumpf et al., 2014). Additionally, changes in snowmelt timing can affect soil moisture availability, further influencing plant growth dynamics (Li et al., 2020). 4.4 Case studies of plant species affected by snow cover dynamics Several studies have documented species-specific responses to changes in snow cover. For instance, in the Swiss Alps, earlier snowmelt reduced aboveground growth in three out of four dwarf-shrub species studied, with only Loiseleuria procumbens benefiting from the advanced snowmelt. In the Arctic, deeper snow with later melt-out had varied effects on different plant species, underscoring the importance of species-level investigations (Wang et al., 2018). In temperate grasslands, increased winter snowfall stabilized plant community composition and productivity, particularly benefiting grasses by enhancing root biomass and soil moisture during the early growing season. These case studies illustrate the diverse and complex impacts of snow cover dynamics on plant species across different ecosystem. 5 Interrelationship Between Snow Cover, Soil Moisture, and Plant Growth 5.1 Integrated effects on ecosystem productivity Snow cover plays a crucial role in determining soil moisture levels, which in turn significantly impacts plant growth and overall ecosystem productivity. In temperate regions, thicker snow cover and later snowmelt generally result in increased soil moisture, which can enhance the start date of the growing season (SGS) and subsequently increase spring carbon uptake (Chen et al., 2019). This is particularly important in water-limited areas where the additional moisture from snowmelt can extend the growth period and boost gross primary production (GPP). Similarly, in temperate grasslands, deepened winter snow has been shown to increase soil moisture in the early growing season, particularly in deeper soil layers, which enhances net ecosystem exchange (NEE) and stabilizes plant community composition and productivity (Li et al., 2020). However, the effects of snow cover on ecosystem productivity can vary depending on the specific environmental conditions and the timing of snowmelt. 5.2 Feedback mechanisms between snow cover and vegetation The relationship between snow cover and vegetation is characterized by complex feedback mechanisms. For instance, increased snow depth can lead to higher soil moisture levels, which promote plant growth and extend the growing season. This, in turn, can enhance photosynthesis and carbon uptake, creating a positive feedback loop (Wang et al., 2018). However, in wetter regions, thicker snow cover with later snowmelt can delay the start of the growing season, reducing spring GPP and potentially leading to water stress during the summer if subsequent precipitation is insufficient. Additionally, changes in snow cover can influence plant community structure. For example, deepened winter snow in arid grasslands has been found to stabilize plant community composition by reducing resource competition and promoting coexistence between different plant functional groups. These feedback mechanisms highlight the intricate interplay between snow cover, soil moisture, and vegetation dynamics.
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