Impacts of habitat fragmentation in a warming world

全球变暖现在已成为不可否认的现实，物种范围的变化、生命周期事件的季节性变化和体型的缩小被认为是对气温升高的三种普遍反应。政府间气候变化专门委员会预测，全球地表温度平均上升1.5-4.5摄氏度，预计北极地区的升幅更大。此外，高纬度生态系统物种数量少，地理位置孤立，使其特别脆弱，最近有人提出，这些生态系统可作为全球变暖潜在影响的预警指标。与此同时，人类正在对自然生态系统施加巨大的变化，栖息地破碎化被认为是对生物多样性的主要威胁之一。为了满足日益增长的全球粮食需求，农业扩张使自然景观被商业上重要的作物的单一种植分割成更小、更孤立的片段。我的研究将研究全球变化的这两个主要组成部分的相互作用，以及它们对陆地社区的影响。我将确定自然群落聚集的方式--这是收获的生态系统中的一个关键过程，它不断地被重置到演替的早期阶段。然后，我将评估变暖和碎片化如何改变这一过程，以及这对我们获得的生态系统服务可能造成的危害。我还将确定气候变暖和碎片化对陆地食物网结构的影响，特别关注大型捕食者的损失如何破坏农业系统中的害虫控制。这将对作物产量和质量产生重要影响。我将通过在我的研究系统中模拟严重的洪水来评估这些社区对极端事件的适应能力。我将通过用我收集的数据测试预测模型来提高我们对变暖对陆地生态系统影响的可预测性。这些发现将有助于在持续的全球变化面前为保护管理提供信息，以及农业和土地使用政策，以及我们对自然群落如何应对气候和人为干扰的一般理解。

Global warming is now an undeniable reality, with species range shifts, seasonal shifts in life cycle events, and reduced body size recognised as three universal responses to increasing temperature. The Intergovernmental Panel on Climate Change has forecast an average 1.5-4.5 C increase in global surface temperatures, with even stronger increases predicted for Arctic areas. In addition, the small species pool and geographic isolation of high latitude ecosystems makes them particularly vulnerable, with recent suggestions that they may act as early-warning indicators to the potential impacts of global warming. At the same time, humans are exerting great change on natural ecosystems, with habitat fragmentation recognised as one of the major threats to biodiversity. Agricultural expansion to meet growing global food demands has seen natural landscapes divided up into smaller, and more isolated fragments by monocultures of commercially important crops. My research will study the interaction of these two major components of global change and the effect they have on terrestrial communities. I will determine the manner in which natural communities assemble - a critical process in harvested ecosystems, which are continually reset to early stages of succession. I will then assess how warming and fragmentation alter this process and how detrimental that might be to the ecosystem services we derive. I will also determine the impact of warming and fragmentation on the structure of terrestrial food webs, with a particular interest in how loss of larger predators may undermine pest control in agricultural systems. This will have important implications for crop yield and quality. I will assess the resilience of these communities to extreme events, by simulating severe flooding in my study systems. And I will improve our predictability of warming impacts on terrestrial ecosystems by testing predictive models with the data I collect. The findings will help to inform conservation management in the face of continuing global change, as well as agriculture and land use policy, and our general understanding of how natural communities respond to climatic and human-induced disturbances.