Species Diversity and Abundance in Insular Systems

岛屿系统的物种多样性和丰富度

• 批准号: 9020052
• 负责人: Thomas Schoener
• 金额: $ 39.19万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-03-01 至 1994-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9020052&HistoricalAwards=false
• 关键词: Species; Diversity; Abundance; Insular; Systems

This proposal seeks continuing support for research on food- web structure, species extinctions and ecological interactions. Small islands are used as a model system, because they are numerous, simple, discrete and have species and trophic types in various combinations. How top predators affect intermediate predators, ambient insects and foliage damage is studied in an introduction experiment of lizards onto small islets. The same phenomena, plus the degree to which intermediate predators compensate in top-predator absence, is studied in a lizard/spider removal experiment in large enclosures. A second experiment will measure spider competition with and without lizards. Natural extinction is studied using a system of over 100 islands; we focus on the effect of top predators on spider extinction rate, and on how extinction rate varies with mean, variability and skewness of population-size values over time and with life- history characteristics. Spatial patchiness in spider population distributions will be studied both between islands and within larger islands; the latter will be related to top predator occurrence and density. Characteristics of the founder effect (loss of genetic variability; degree of morphological and behavioral change) will be assessed for colonizing populations of lizards introduced onto islands during earlier support periods. The results will provide very valuable information on news relating to global the interactions leading to extinctions.

这项提议寻求继续支持关于食物网结构、物种灭绝和生态相互作用的研究。小岛屿被用作模式系统，因为它们数量众多、简单、离散，并具有各种组合的物种和营养类型。在一项将蜥蜴引入小岛的实验中，研究了顶端捕食者如何影响中间捕食者、环境昆虫和树叶损害。同样的现象，加上中间捕食者在没有顶端捕食者的情况下的补偿程度，在大型围栏中的蜥蜴/蜘蛛清除实验中进行了研究。第二个实验将测量有无蜥蜴的蜘蛛竞争。我们使用一个由100多个岛屿组成的系统来研究自然灭绝；我们重点研究顶级捕食者对蜘蛛灭绝速度的影响，以及灭绝速度如何随着种群大小值随时间的平均值、变异性和偏度以及生活史特征的变化而变化。将研究蜘蛛种群分布的空间斑块，包括岛屿之间和较大岛屿内的空间斑块；后者与顶端捕食者的发生和密度有关。创始人效应的特点(遗传变异性丧失；将对早期支持期间引入岛屿的蜥蜴种群的定殖化程度进行评估。这些结果将为有关导致物种灭绝的全球相互作用的新闻提供非常有价值的信息。