RUI: Grass Effects on Tree Seedling Success in the Pairie-Forest Border: Competition and Facilitation along a Multiple Resource Gradient

尽管水在干旱和半干旱环境中的重要性，以及围绕竞争和资源梯度的大量工作，还没有研究将根和芽竞争的影响沿着土壤水分梯度分开。这些信息是至关重要的，如果我们要了解生态学的木材幼苗建立在草原社区。 这项研究将探讨在干旱和半干旱环境中建立木本幼苗。一个大的多因素的现场实验将在雪松溪LTER网站，其中水输入，氮输入和竞争的草将被操纵。本实验将允许量化根，芽和整个植物的竞争，草沿着水氮梯度。它也将允许一个独立的量化之间的根和芽的竞争强度的树木幼苗（大果栎和Q。椭圆体）在上述组合中的每一个中。这项研究应提供重要的新信息的影响，资源供应的草和树木之间的竞争相互作用。虽然在一个单一的网站上实施，研究应该有广泛的影响，竞争理论，因为它涉及到水和养分，并预测植物对自然和人为干扰的反应。这项研究的结果应有助于了解全球和区域环境的变化，包括氮沉降水平的增加，降水量的变化，以及外来草替代本地草可能会影响草地群落中的木本幼苗建立。

9873673Davis Despite the importance of water in arid and semi-arid environments and the numerous amount of work centered around competition and resource gradients, no studies have been made to separate out the effects of root and shoot competition along a soil water gradient. This information is critical if we are going to understand the ecology of wood seedlings establishment in grassland communities. This research will examine the establishment of woody seedlings in arid and semi-arid environments. A large multi-factor field experiment will be undertaken at the Cedar Creek LTER site in which water input, nitrogen input and competition from grasses will be manipulated. This experiment will permit the quantification of root, shoot and whole plant competition by grasses along the water-nitrogen gradient. It will also allow an independent quantification of root and shoot competition intensity between the tree seedlings (Quercus macrocarpa and Q. ellipsoidalis) in each of the above combinations. This research should provide important new information on the effect of resource supply on competitive interactions between grasses and trees. Although implemented at a single site, the research should have broad implications for competition theory as it relates to water and nutrients and for predicting plant response to natural and human-caused disturbance. Findings from this proposed research should help in understanding how global and regional changes in the environment involving increased levels of nitrogen deposition, changes in precipitation, and replacement of native by exotic grasses my be affecting woody seedling establishment in grassland communities.