Are Effects of Forest Fragmentation on Avian Nesting Success Mediated by Landscape Composition

森林破碎化对鸟类筑巢成功的影响是由景观构成介导的吗

• 批准号: 9904058
• 负责人: Scott Robinson
• 金额: $ 36.72万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-12-15 至 2003-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9904058&HistoricalAwards=false
• 关键词: Effects; Forest; Fragmentation; Avian; Nesting

9904058RobinsonHabitat fragmentation fundamentally affects community structure and trophic interactions. Numerous studies of forest birds support the widely held notion that the fragmentation of breeding habitat significantly decreases annual reproductive success. The mechanisms underlying this effect are generally reported as increased rates of nest predation and brood parasitism. Nonetheless, most studies have focuses on local, patch-specific features of fragmentation such as distance to edge and tract size. Less consideration has been given to the broader landscape outside forest fragments. Indeed, recent evidence suggests that the effects of fragmentation on forest birds change with landscape composition. Interactions between local and landscape processes are poorly understood, but potentially complex because many processes co-vary with the magnitude of forest fragmentation. This study will assess directly how landscape composition affects the outcome of fragmentation on birds nesting in southern Illinois. This region contains over 500,000 ha of forest in landscapes that vary widely in the amount of forest cover and relative coverage of different non-forest cover types (crops versus grassland). This study will first classify habitat type surrounding forest patches. Then, replicate patches will be selected in four different landscapes (high and low fragmentation in grassland or crop matrix) in which studies of reproductive success of songbirds will be measured. Factors affecting song bird reproductive success include brood parasitism, nest predation and alteration of understory vegetation by deer browsing. These factors will then be quantified and related to reproductive success. Results of this study will inform local and regional conservation strategies and will constitute a unique case history of how and why local demographic processes can be conditional upon larger-scale phenomena.

9904058RobinsonHabitat碎片化从根本上影响群落结构和营养相互作用。大量的森林鸟类研究支持了一个普遍的观点，即繁殖栖息地的破碎化显着降低了每年的繁殖成功率。这种效应的机制通常被报道为巢捕食和育雏寄生率增加。尽管如此，大多数研究都集中在本地，斑块特定功能的碎片化，如距离边缘和道的大小。对森林碎片以外的更广泛景观的考虑较少。事实上，最近的证据表明，破碎化对森林鸟类的影响随着景观组成的变化而变化。人们对当地进程和地貌进程之间的相互作用了解甚少，但可能很复杂，因为许多进程随着森林破碎化程度的变化而变化。本研究将直接评估景观组成如何影响在伊利诺伊州南部的鸟类筑巢破碎的结果。这一地区有50多万公顷森林，其景观在森林覆盖量和不同非森林覆盖类型（作物与草地）的相对覆盖率方面差异很大。本研究将首先对森林斑块周围的生境类型进行分类。然后，复制补丁将被选择在四个不同的景观（高和低碎片草地或作物基质），其中鸣禽繁殖成功的研究将被测量。影响鸣禽繁殖成功的因素包括雏鸟寄生、巢被捕食和鹿食草改变林下植被。这些因素将被量化，并与生殖成功有关。这项研究的结果将告知当地和区域的保护战略，并将构成一个独特的案例历史，如何以及为什么当地的人口过程可以有条件的大规模的现象。