Dissertation Research: Spatial Interactions and the Role of Facilitation in a Colorado Desert Plant Community

小行星9412117 本研究的目的是实验测试的假设来自人口普查和五年的recensus的7500映射木本多年生植物的26种约书亚树国家纪念碑。多数种表现出较强的种内和种间聚集性，以及作用不明的植食性。将根据定于1994年3月进行的10年一次的重新人口普查来解释试验结果。 使用周围的成员占主导地位的木本多年生植物和附近的开放区域的外壳，我们建议区分内和种间竞争，granivory，草食动物，干燥，并促进建立，生长，和/或死亡率的新幼苗超过两年，并在生长和死亡率的幼苗，和青少年已经存在的影响。使用受保护和不受保护的移植苗，我们希望测试的竞争和便利的控制样品的长寿的多年生植物，是不是由脊椎动物食草动物，短命的多年生植物，是严重浏览长耳大野兔，对一个标准的优势灌木，遭受中度到重度脊椎动物食草动物的幼苗。展览和移植将区分过程，占广泛的裸露地面和聚集的空间分散的关键木本多年生植物在这个网站上常见。 本论文的研究提供了一个很好的整合的地图数据，从永久样地与实地实验，以评估一些重要的决定因素的空间格局和植物协会在一个沙漠社区。

9412117 Howe The purpose of this research is to experimentally test hypotheses derived from a census and five-year recensus of 7500 mapped woody perennials of 26 species in Joshua Tree National Monument. Most of these species show strong intraspecific and interspecific aggregation, and herbivory of unknown effect. Experimental results will be interpreted in light of a 10-year re-census, scheduled for March 1994. Using exclosures around members of the dominant woody perennial and in open areas nearby, we propose to distinguish effects of intra- and interspecific competition, granivory, herbivory, desiccation, and facilitation in establishment, growth, and/or mortality of new seedlings over two years, and in growth and mortality of seedlings, and juveniles already present. Using protected and unprotected transplants of seedlings, we expect to test effects of competition and facilitation of controlled samples of a long-lived perennial that is not browsed by vertebrate herbivores, a short-lived perennial that is heavily browsed by jackrabbits, against a standard seedlings of the dominant shrub, which suffer moderate to heavy vertebrate herbivory. Exclosures and transplants will distinguish processes that account for extensive bare ground and aggregated spatial dispersions of key woody perennials common at this site. %%% This dissertation research provides a nice integrate map data from permanent plots with field experiments to assess some of the important determinants of spatial pattern and plant associations in a desert community.