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

近年来，各国政府已开始通过保护野生动物走廊，将公园和其他大型自然区域连接起来。野生动物走廊是指允许动物在自然区域之间自由流动的半自然地带。人们希望这些相互连接的地区能够维持庞大的、基因多样化的种群和生态过程，比如授粉和种子传播。但是，几乎没有科学来指导如何将野生动物走廊付诸实践，并将其成本降至最低，包括限制人类使用土地的成本。走廊内允许设置多少种类型的围栏、道路、牧场、花园和建筑物？走廊需要有多宽？是否有些野生动物比其他物种更容易使用走廊？我们认为我们对走廊的大部分了解来自于在3英亩的栖息地斑块上进行的小型实验，这些栖息地由100英尺宽的走廊连接，附近没有人类活动，并使用动物的存在或运动来衡量走廊的有效性。这项研究将涉及100倍大的走廊和斑块，以及附近有各种人类活动的景观。此外，该项目将使用遗传学而不是动物的存在或运动来更好地衡量走廊的效果。通过这些创新和测量多种物种的反应，本研究将帮助科学家了解走廊的有效性。它还将帮助社会实施有效的走廊，同时最大限度地降低各种成本。本研究将利用50-200年稳定的大型廊道和生境斑块，使遗传格局反映景观格局的影响。每个景观都包含一个连接两个自然斑块的廊道和两种参考条件，即两个缺乏连接的斑块与被连接的斑块大小和斑块间距大致相同，以及一个包含两个大小和间距相似的采样地点的完整自然区域。该研究将使用20个独立的景观来量化走廊特征如何影响基因流动，并将使用非飞行哺乳动物作为焦点物种，因为它们受到碎片化的强烈影响。研究小组假设：(1)成功（基因流）随走廊长度呈强烈的非线性下降，反映了物种内传播距离的倾斜分布；(2)走廊宽度小于一定阈值时，成功率急剧下降，阈值由物种特征决定；(3)体型较大的物种，是栖息地专家，或具有更大的传播能力（相对于大脑大小或繁殖率）将从走廊中获益更多。测试这些假设将允许推广到广泛的哺乳动物物种不包括在这个项目。我们将使用高度灵活的随机森林模型来回答最重要的问题：哪些景观特征（如走廊宽度、人为干扰程度）和物种特征（流动性、对特定土地覆盖类型的亲和力）与有效走廊相关？该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In recent years, governments have begun to connect parks and other large natural areas by conserving wildlife corridors – swaths of semi-natural land intended to allow the free flow of animals between natural areas. The hope is that the connected areas will sustain large, genetically diverse populations and ecological processes, such as pollination and seed dispersal. But there is little science to guide how wildlife corridors are put into practice and to minimize their costs, including costs of restricting human uses of the land. How many and what types of fences, roads, pastures, gardens, and buildings can be permitted in the corridor? How wide do corridors need to be? Do some wildlife species use corridors more readily than others? Most of what we think we know about corridors comes from small experiments on 3-acre patches of habitat connected by 100-ft-wide corridors with no human activities nearby, and using animal presence or movement to measure corridor effectiveness. This study will involve corridors and patches 100 times larger, and in landscapes with various human activities nearby. Furthermore, this project will use genetics instead of animal presence or movement as a better way to measure how well corridors work. By these innovations and by measuring responses of multiple species, this study will help scientists understand corridor effectiveness. It will also help society implement corridors that are effective while minimizing all sorts of costs. This study will use large corridors and habitat patches that have been stable for 50-200 years, so that genetic patterns reflect the influence of landscape pattern. Each landscape contains a corridor connecting two natural patches and two types of reference conditions, namely two patches lacking a connection that are about the same size and interpatch distance as the connected patches, and an intact natural area containing two sampling locales with similar size and spacing. The study will use 20 independent landscapes to quantify how corridor traits affect gene flow, and will use non-flying mammals as focal species because they are strongly affected by fragmentation. The research team hypothesizes (1) a strong non-linear decline in success (gene flow) with corridor length, reflecting the skewed distribution of dispersal distances within species; (2) success will drop steeply as corridor width falls below a threshold, with the threshold determined by species traits; and (3) species that are bigger, are habitat specialists, or have greater dispersal abilities (relative to brain size or reproductive rate) will benefit more from corridors. Testing these hypotheses will allow generalization to a wide range of mammal species not included in this project. We will use highly flexible Random Forest models to answer the overarching question: What landscape traits (e.g., corridor width, degree of human disturbance) and species traits (mobility, affinity to particular land cover types) are associated with effective corridors?This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.