Tests of the Equiv#aence of Competitors and Asymmetry of Competition Hypotheses in Multispecies Woody Communities

尽管竞争对生态环境至关重要， 理论，关于植物竞争的假设的实地测试是 罕见. 目前的两个主要假设是： 对等假设与不对称竞争 假说. 没有尝试应用这些 木本植物群落的假说。 私家侦探提议 这些实验将测试竞争等效性 假设和不对称竞争假设 Alleghaniensis和Fagus grandifolia。 的 拟议的研究基于三个工作假设： 1)地面上对光线的竞争是平等的或更大的 对幼苗的生长和存活的重要性， 对土壤资源的地下竞争。 这是一 其余两个假设的基本假设。 2)目标幼苗对相同密度的 不同物种的相似大小的邻居。 这是 竞争等价假设。 3)目标幼苗将 显示出增长的减少与 不同大小的邻居的密度相等。 这是空值 不对称竞争假说。 的 调查人员将在市中心周围建立复制的社区， 通过减少现有的高密度区域， 留下所需密度、种类和大小的邻居。 目标幼苗的反应将被测量为高度的增长 和茎粗，并分析为相对生长速率。 将在两年内对答复进行衡量， 治疗 结果将决定上述假设是否 准确地描述了这些竞争之间的相互作用， 木本物种以及物种在竞争中的差异 彼此的影响。

Despite the central importance of competition in ecological theory, field tests of hypotheses about plant competition are rare. Two current major hypotheses are the Competitive Equivalence Hypothesis and the Asymmetrical Competition Hypothesis. No attempts have been made to apply these hypotheses to woody plant communities. The P.I.s propose experiments that will test both the Competitive Equivalence Hypothesis and the Asymmetrical Competition Hypothesis using individuals of Betula alleghaniensis and Fagus grandifolia. The proposed research is based on three working hypotheses: 1) Aboveground competition for light is of equal or greater importance to the growth and survival of seedlings than belowground competition for soil resources. This is an underlying assumption of the remaining two hypotheses. 2) Target seedlings will respond equally to equal densities of similar-sized neighbors of different species. This is the Competitive Equivalence Hypothesis. 3) Target seedlings will show reductions in growth directly proportional to the sizes of equal densities of different-sized neighbors. This is the null form of the Asymmetrical Competition Hypothesis. The investigators will create replicated neighborhoods around central target individuals by thinning existing high-density areas to leave neighbors of the desired density, species, and size. Response of target seedlings will be measured as growth in height and stem diameter, and analyzed as relative growth rate. Responses will be measured over two years from the time of treatment. Results will determine whether the above hypotheses accurately describe the competitive interactions among these woody species and how the species differ in their competitive effects on one another.