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Dissertation Research: Competition Between Herbaceous and Woody Plants: The Importance of Herbs in Forest Dynamics

论文研究：草本植物和木本植物之间的竞争：草本植物在森林动态中的重要性

基本信息

批准号：
9122920
负责人：
金额：
$ 0.85万
依托单位：
University of North Carolina at Chapel Hill
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
1992
资助国家：
美国
起止时间：
1992-04-01 至 1994-03-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9122920&HistoricalAwards=false
关键词：
Dissertation Research Competition Between Herbaceous

项目摘要

Although herbs typically contribute only a minor fraction of the total biomass or production of a forest, they may be critically important in regulating forest composition and dynamics through competition with tree seedlings. However, because forests are extremely variable in herb abundance, the impact of herbs on tree establishment is not consistent. Resource competition theory leads to the prediction that under conditions of abundant soil nutrients and moisture but low light, herbaceous plants will win in competition with woody plants, while higher light or lower soil resource levels should shift the competitive interaction to favor woody plants. Experimental manipulations of light and soil resources will be used the hypothesis that herbs on high-resource sites influence tree composition by reducing growth rates, and increasing mortality rates of tree seedlings. Observation made along herb-cover gradients will be used to test the general hypothesis that the light:soil resource supply ratio determines the outcome of competition between woody and herbaceous plants in understories. If this hypothesis is true, then canopy gaps, herb removal areas, and other low resource microsites could play a critical role by shifting the competitive balance to be more favorable for tree seedlings.

虽然草药通常只贡献一小部分，森林的总生物量或生产量，它们可能是对调节森林组成至关重要，通过与树苗的竞争动态。然而，在这方面，因为森林中的草本植物丰富度变化很大，草本植物对树木建立的影响并不一致。根据资源竞争理论，土壤养分和水分丰富但光照不足的条件下，草本植物将在与木本植物的竞争中获胜，而更高的光照或更低的土壤资源水平应该改变竞争性相互作用有利于木本植物。实验光和土壤资源的操纵将被使用，高资源地草本植物对树木影响假说通过降低增长率和增加死亡率，树苗率。沿着草本覆盖物观察梯度将被用来测试的一般假设，光：土壤资源供给比例决定了林下木本和草本植物之间的竞争。如果这个假设是正确的，那么林冠空隙，草本植物移除区，和其他低资源微型网站可以发挥关键作用，改变竞争平衡，使之对树木更有利幼苗