在过去的半个世纪中，森林生态系统物质能量流动模型的发展使得生态学者对矿物元素的来源、去处、转换速率及其干扰破坏的影响有了进一步的认识。其中“春坝”假设提出：在早春来临之际，林冠树木仍处于冬眠之时，林下地被植物先于林冠树木发芽开花，吸收土壤养分于植物体内，使得养分免于因雨水或雪水而造成的淋失而得以保留于森林生态系统中。本文对“春坝”假设的研究作一小结。现有的研究结果显示，早春地被植物对土壤氮的吸收量因不同生态系统而异；而土壤微生物对氮的吸收量远高于过去人们所认识的水平。早春地被物与土壤微生物都能在季节的变化中吸收土壤养分、共同起着“春坝”作用。两者所起作用大小因气候及生态系统的不同而有所改变。
Over the past half century the development of ecosystem models which quantify material and energy flows through forest ecosystems have led ecologists to identify and characterize the various sources, sinks, and flux rates of mineral nutrients and how these are affected by disturbance. The “Vernal Dam" hypothesis suggests that during the early spring months when nutrient susceptibility to loss is highest, an ephemeral herbaceous community takes up nutrients in biomass as a mechanism to retain nutrients in the system. This paper evaluates evidence from several studies regarding the “Vernal Dam" hypothesis. The uptake of nutrients in plant biomass during the early spring months is highly variable across ecosystems, and microbial immobilization is a more important mechanism for retaining nutrients than traditionally thought. Suggestions are made for future research which considers the role of plants and microbes as a “Vernal Dam", and how the roles of plants and microbes change under different climatic conditions and ecosystem types.