NSFDEB-NERC-Wildlife corridors: do they work and who benefits?

人类改变了全球75%以上的陆地面积，对生物多样性造成了巨大的负面影响。一个主要后果是，曾经的大型自然栖息地已经分裂成农场和城市等人工改良土地海洋中的栖息地小岛。大多数物种依靠扩散(个体从出生的地方迁移到不同的地点)来维持不同景观中的健康种群。当它们的栖息地变得支离破碎时，物种往往无法在残留的斑块之间有效地分散，这往往导致种群下降、遗传多样性丧失和物种局部灭绝。了解如何最好地管理支离破碎的景观是一项关键挑战。对碎片化最有希望的对策之一是保护或恢复野生动物走廊，即在原本孤立的生境斑块之间的大片自然栖息地，以促进扩散、基因流动和种群拯救。事实上，创建走廊是国家(例如英格兰的25年环境计划)和国际(例如联合国的连通性保护项目)环境政策的核心。许多保护和环境机构(例如，自然英格兰，美国的22个景观保护合作社)正在设计--公共和私人保护投资者正在实施--野生动物走廊。巨额的直接开支和失去的发展机会正被投资于走廊。然而，我们缺乏对这种走廊是否起作用的理解。关于走廊功效的大部分已知知识来自于在与真实世界野生动物走廊不相似的模型系统上进行的实验。需要新的研究来解决关键问题：走廊是否能对抗现实世界的碎片化；走廊的哪些特征限制了有效性？为了解决这些问题，我们需要对物种在大规模和复杂的人为修改的景观中传播的生态学进行基础研究。现有关于走廊的实验研究的是长度小于0.5公里、宽度小于0.4公里的走廊的影响，这些走廊比现实世界中的走廊小得多。我们在这个项目中的目标是评估走廊在一些人工修改的景观中的有效性。我们将通过研究欧洲和美洲20个景观中每一个景观中的4-6个焦点物种，来解决关于有效走廊特征的主要知识空白。这20个景观中的每一个都包含三种类型的栖息地配置：孤立的栖息地斑块、由走廊连接的斑块对和大片完好的自然区域。这些景观非常理想，因为它们的走廊宽度(0.2-3公里)和长度(1-25公里)各不相同，这类似于现实中设计栖息地碎片化和走廊的大尺度。使用遗传学方法评估各种哺乳动物物种如何在这些不同的栖息地配置中移动，我们将确定哺乳动物是否能够在如此大的规模下使用走廊，以及哪些走廊特征(如长度、宽度)对成功影响最大。我们将评估不成功的走廊在哪里以及如何失败。我们还将使用新的物种特征分析，如身体大小、扩散能力、大脑大小和繁殖率，以确定哪些类型的物种最有可能受益于走廊，并确定不同类型的物种是否可能需要不同类型的走廊。最后，我们将在生态模型中使用我们的新数据来测试一系列规划野生动物走廊的方法，这将使该项目对全球保护管理者有用。我们的项目将提供关于如何使野生动物走廊成功地适用于各种物种的重要新信息，将对物种在非常大范围内的传播带来新的理解，并将为确定在哪里最好地投入资源进行保护提供新的方法。

Humans have modified over 75% of the global land area, leading to huge, negative impacts on biodiversity. A major consequence is that once large natural habitats have become fragmented into small islands of habitat within a sea of human-modified land such as farms and cities. Most species depend on dispersal (the movement of individuals from where they are born to a different location) to maintain healthy populations across landscapes. When their habitat becomes fragmented into small, isolated patches, species are often unable to disperse effectively between the remnant patches and this frequently results in population declines, loss of genetic diversity and local extinctions of species. Understanding how best to manage landscapes that are fragmented is a key challenge. One of the most promising responses to fragmentation is to conserve or restore wildlife corridors, i.e. swaths of natural habitat between otherwise isolated habitat patches to facilitate dispersal, gene flow, and population rescue. Indeed, corridor creation is at the core of national (e.g. England's 25 Year Environment Plan) and international (e.g. the UN's Connectivity Conservation Project) environmental policies. Many conservation and environment agencies (e.g., Natural England, the USA's 22 Landscape Conservation Cooperatives) are designing - and public and private conservation investors are implementing - wildlife corridors. Huge sums of money in direct expenses and foregone development opportunities are being invested in corridors. However, we lack an understanding of if such corridors work. Most of what is known about corridor efficacy comes from experiments on model systems that do not resemble real-world wildlife corridors. New studies are needed to address the crucial questions: do corridors counter real-world fragmentation; and what corridor characteristics constrain effectiveness? To address these questions, we need to do fundamental research into the ecology of species' dispersal over large-scales and within complex, human-modified landscapes. Existing experiments on corridors study the effects of corridors less than 0.5km long and less than 0.4km wide, much smaller than corridors in the real world. Our objective in this project is assess corridor effectiveness in a number of human-modified landscapes. We will address major knowledge gaps about the characteristics of effective corridors by studying 4-6 focal species in each of 20 landscapes in Europe and the Americas. Each of these 20 landscapes contains three types of habitat configurations: isolated habitat patches, pairs of patches connected by a corridor, and a large intact natural area. The landscapes are ideal because they vary in corridor widths (0.2-3km) and lengths (1-25km), which resembles the large scales at which habitat fragmentation and corridors are design in reality. Using genetic methods to assess how a variety of mammal species move in these different habitat configurations, we will identify whether mammals are able to use corridors at these large scales and which corridor characteristics (e.g. length, width) most strongly influence success. We will assess where and how unsuccessful corridors fail. We will also use novel analysis of species characteristics, such as body size, dispersal ability, brain size and reproductive rate, to identify which types of species are most likely to benefit from corridors and determine whether different types of species might require different types of corridors. Finally, we will use our new data in ecological models to test a range of methods for planning wildlife corridors, which will make the project useful to conservation managers globally. Our project will deliver vital new information on how to make wildlife corridors successful for a large variety of species, will bring new understanding into species dispersal over very large scales, and will provide new methods for determining where to best invest resources for conservation.