Collaborative Research: Testing for Cascading Effects of Habitat Fragmentation

合作研究：测试栖息地破碎化的级联效应

• 批准号: 0317085
• 负责人: James Diffendorfer
• 金额: $ 25万
• 依托单位: San Diego State University Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-10-01 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0317085&HistoricalAwards=false
• 关键词: Collaborative; Research; Testing; Cascading; Effects

Collaborative Research: Testing for Cascading effects of Habitat FragmentationDiffendorfer, James, F.San Diego State UniversityFood web theory provides a useful framework for management of ecosystems, and compliments well the more traditional population-level approach. However, the applicability of food web concepts, including keystone species and top-down cascades, to ecosystems of conservation concern is unclear. This project will study changes in predator-prey interactions in the coastal sage scrub ecosystem of southern California cause by habitat fragmentation, associated with urban development. This project focuses on four landscape treatments in coastal San Diego County that vary in the degree of exposure to urban edge and fragmentation: interior of large habitat blocks (1000ha), urbanized edge of large blocks, large habitat fragments (50-100 ha) and small fragments (5-20 ha). The proposed research will expand previous work by continuing demographic studies on birds, but with simultaneously estimation of mesocarnivore, snake, and raptor abundance and activity to estimate their impacts and examine how these vary with habitat fragmentation. The work will determine if nest predation, juvenile and adult bird survival, as well as small mammal abundance and survival vary with fragment size and predator composition. In addition, it will investigate the role of snakes, and raptors and determine their impact relative to mammalian predators by comparisons across experimental treatments and by path analysis. By comparing bird responses to small mammals this project will address the question of whether all primary consumers are vulnerable to cascades, or if the biological differences between taxa make one group more susceptible to top-down regulation than another. Overall, this project will train 18-25 undergraduates, 3 graduate students and a post-doctoral student, and will creating research opportunities for underrepresented students participating in an NSF Undergraduate Mentoring in Environmental Biology teaching program. In addition, this research will directly benefit ongoing management and reserve design objectives of local wildlife agencies and nonprofit, land management organizations.

合作研究：食物网理论为生态系统的管理提供了一个有用的框架，并很好地补充了更传统的人口水平的方法。 然而，食物网概念，包括关键物种和自上而下的级联，对受养护关注的生态系统的适用性尚不清楚。 本计画将研究因都市发展造成之栖地破碎化，在南加州海岸鼠尾草灌丛生态系中，捕食者-猎物互动之变化。 该项目的重点是四个景观处理在沿海圣地亚哥县，不同程度的暴露于城市边缘和碎片：大型栖息地块（1000公顷），大型块，大型栖息地片段（50-100公顷）和小片段（5-20公顷）的城市化边缘的内部。 拟议的研究将通过继续对鸟类进行人口统计学研究来扩展以前的工作，但同时估计中食肉动物，蛇和猛禽的丰度和活动，以估计它们的影响，并研究这些如何随着栖息地碎片化而变化。 这项工作将确定巢捕食，幼年和成年鸟类的生存，以及小型哺乳动物的丰度和生存与碎片大小和捕食者的组成。 此外，它将研究蛇和猛禽的作用，并通过比较实验处理和路径分析来确定它们相对于哺乳动物捕食者的影响。 通过比较鸟类对小型哺乳动物的反应，该项目将解决这样一个问题：是否所有的初级消费者都容易受到级联效应的影响，或者分类群之间的生物差异是否使一个群体比另一个群体更容易受到自上而下的监管。 总体而言，该项目将培养18-25名本科生，3名研究生和一名博士后，并将为参加NSF环境生物学本科生导师教学计划的代表性不足的学生创造研究机会。 此外，这项研究将直接有利于当地野生动物机构和非营利土地管理组织的持续管理和保护区设计目标。