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

近年来，各国政府已经开始通过保护野生动物走廊来连接公园和其他大型自然区域。野生动物走廊是一大片半自然的土地，旨在允许动物在自然区域之间自由流动。人们希望，这些相连的地区将维持庞大的、遗传多样性的种群和生态过程，如授粉和种子传播。但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。走廊中允许使用多少种类型的栅栏、道路、牧场、花园和建筑？走廊需要多宽？一些野生动物物种是否比其他物种更容易使用走廊？我们认为我们对走廊的了解大多来自于在3英亩的栖息地上进行的小型实验，这些栖息地由100英尺宽的走廊相连，附近没有人类活动，并使用动物的存在或移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，作为衡量走廊工作情况的更好方法。通过这些创新，通过测量多个物种的反应，这项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，同时将各种成本降至最低。这项研究将使用已经稳定了50-200年的大型廊道和栖息地斑块，以使成因模式反映景观格局的影响。每个景观包括一条连接两个自然斑块和两种参考条件的走廊，即两个没有连接的斑块，其大小和斑块之间的距离与连接的斑块大致相同，以及一个完整的自然区域，其中包含两个大小和间距相似的采样点。这项研究将使用20个独立的景观来量化走廊特征如何影响基因流，并将使用非飞行哺乳动物作为重点物种，因为它们受到碎片的强烈影响。研究小组假设(1)成功率(基因流动)随走廊长度的强烈非线性下降，反映了物种内部扩散距离的扭曲分布；(2)随着走廊宽度降至阈值以下，成功率将急剧下降，阈值由物种特性决定；(3)更大、更具栖息地专家、或具有更大扩散能力的物种(相对于大脑大小或繁殖率)将从走廊中受益更多。检验这些假说将允许对不包括在该项目中的广泛的哺乳动物物种进行推广。我们将使用高度灵活的随机森林模型来回答最主要的问题：哪些景观特征(例如，走廊宽度、人类干扰程度)和物种特征(机动性、对特定土地覆盖类型的亲和力)与有效的走廊相关？该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.