Feedbacks Between Species Composition and Ecosystem Nutrient Cycling in a California Grassland

加州大学伯克利分校物种组成与生态系统养分循环之间的反馈本研究调查了物种组成对加州沿海草原生态系统土壤氮素循环的影响。虽然大多数低海拔的加州草原以前主要是原产于加州的多年生束草，但欧亚一年生草本植物和杂草的入侵，以及最近的欧亚多年生草本植物的入侵，导致它们的组成发生了戏剧性的变化。我们对这种成分变化对土壤氮的循环和保持的后果知之甚少--土壤氮是限制这些生态系统中植物生长的一种基本养分。本研究的目的是调查当地多年生牧草与欧亚一年生或多年生牧草对氮素的吸收和利用的差异是否会导致每种类型牧草主导的地块中氮素循环和淋失的差异。我们特别感兴趣的是，植被组成和土壤氮素循环是否相互作用，使群落抵抗进一步的组成变化。

DEB-9910008Carla D'Antonio- University of California at BerkelyFeedbacks between species composition and ecosystem nutrient cycling in a California grassland This research investigates the effect of species composition on the cycling of nitrogen in soil of a California coastal prairie ecosystem. While most low-elevation California grasslands were formerly dominated by perennial bunchgrasses native to California, invasion by Eurasian annual grasses and forbs and, more recently, Eurasian perennial grasses, has caused a dramatic shift in their composition. We know very little about the consequences of this compositional change for the cycling and retention of soil nitrogen - an essential nutrient that limits plant growth in these ecosystems. The aim of this study is to investigate whether differences in nitrogen uptake and use by native perennial grasses, versus Eurasian annual or perennial grasses leads to differences in nitrogen cycling and leaching in plots dominated by each type of grass. We are particularly interested in whether vegetation composition and soil nitrogen cycling interact to make communities resistant to further compositional changes.