Using Spatial and Genetic Tools to Understand Functional Connectivity in a Patchy Landscape

这个项目调查了栖息地碎片化对早期演替的栖息地专家--新英格兰棉尾巴在斑驳景观中的扩散和连通性的影响。在全球范围内，人类活动最普遍的影响是土地利用和土地覆盖的变化以及与之相关的栖息地碎片化。了解自然人口如何对景观特征作出反应并在景观范围内恢复连通性，对于今天有效地保护生物多样性以及规划应对气候变化的管理至关重要。景观结构和连通性问题以及动物运动与景观异质性的关系也是景观生态学领域的中心主题。通过调查早期演替和灌木生境的未被研究的生态系统中的景观连通性，该项目将把碎片化理论扩展到森林生态系统之外。由早期演替生境组成的景观为检验动物扩散和碎片化理论假说提供了一个理想的框架，因为它们本质上是短暂的和零散的，并且受到人类对景观的修改和土地利用变化的严重影响。该项目将以景观遗传学的方法，应用遥感地理工具和种群遗传学技术进行空间分析，以确定景观特征在促进和阻碍棉尾巴扩散方面的影响。早期演替和灌木生境将利用中到高分辨率遥感数据集进行表征和测绘，这些遥感数据包括无源光学、激光雷达和雷达。景观和扩散模型将使用最小成本路径、阻力隔离和图论进行。通过对不同生境破碎化程度和种群密度的多个复制景观的比较，这项研究将检验关于碎片化和有效种群规模对遗传结构、扩散距离和性别偏见扩散模式的影响的假设，以及道路作为扩散障碍和早期演替生境专家的促进器的双管齐下的效应。结果将被综合起来，以开发与景观结构相关的棉尾基因流模型和预测模型，以确定连通性热点并估计恢复景观中斑块特定的殖民概率。该项目有助于实现减轻人类改变景观对自然人口和生态系统的影响的社会目标。通过将重点放在栖息地不断衰落的早期演替森林中的受威胁物种新英格兰棉尾鱼上，该项目将产生直接用于恢复脆弱生态系统的信息。保持包括所有演替阶段的森林景观的马赛克将增强生物多样性，并保持这一地理区域的生态完整性，该区域继续经历大规模的人为景观变化。通过确定景观如何影响棉尾鱼的扩散模式和连通性，以及确定维持种群持续存在的关键走廊，该项目将为栖息地恢复和保护这种受威胁的物种提供关键的见解。通过与州和联邦机构生物学家建立伙伴关系，该项目的结果与利益相关者共享，确保它们将产生最大的保护影响。该项目将有助于培养一名研究生和几名本科生，并促进自然资源、地理和计算机科学学科之间的跨学科培训。该项目开发的空间工具及其在保护管理中的应用也将纳入本科生和研究生课程。

This project investigates the effects of habitat fragmentation on the dispersal and connectivity of an early successional habitat specialist, the New England cottontail, in a patchy landscape. Among the most pervasive effects of human activities across the globe are changes in land use and land cover and the associated fragmentation of habitat. Understanding how natural populations respond to landscape features and restoring connectivity on a landscape scale are critical for effective biodiversity conservation today as well as planning for management that accounts for climate change. Issues of landscape structure and connectivity and the relationship of animal movements and landscape heterogeneity are also central themes in the field of landscape ecology. By investigating landscape connectivity in an under-studied ecosystem of early successional and shrub habitats, this project will extend fragmentation theory beyond forested ecosystems. Landscapes consisting of early successional habitats present an ideal framework for testing hypotheses about animal dispersal and fragmentation theory because they are ephemeral and patchy by nature and are heavily impacted by human modifications of the landscape and changes in land use. This project will apply geographic tools of remote sensing and spatial analyses with population genetic techniques, in a landscape genetics approach, to identify the influence of landscape features in facilitating and impeding cottontail dispersal. Early successional and shrub habitats will be characterized and mapped using data sets from moderate to high-resolution remote sensors that include passive optical, LiDAR and radar. Landscape and dispersal modeling will be conducted using least cost path, isolation-by-resistance, and graph theory. By comparison across multiple, replicated landscapes with varying degrees of habitat fragmentation and population density, this study will test hypotheses about the effects of fragmentation and effective population size on genetic structure, dispersal distances and sex-biased dispersal patterns and also about the two-pronged effects of roads as dispersal barriers and facilitators for early successional habitat specialists. Results will be synthesized to develop a model of cottontail gene flow in relation to landscape structure and a predictive model to identify hot spots of connectivity and to estimate patch-specific colonization probabilities in restoration landscapes. This project contributes to the societal goal of mitigating consequences of human modifications of the landscape on natural populations and ecosystems. By focusing on a threatened species, the New England cottontail, in a declining habitat, the early successional forest, this project will generate information that will be directly used in the restoration of a vulnerable ecosystem. Maintaining a mosaic of forested landscapes that includes all successional stages will enhance biodiversity and maintain ecological integrity of this geographic region that continues to experience large-scale anthropogenic landscape change. Through identifying how the landscape influences the dispersal patterns and connectivity of cottontails and identifying key corridors to maintain population persistence, this project will provide key insight for habitat restoration and the conservation of this threatened species. Through established partnerships with state and federal agency biologists, the results of this project are shared with stakeholders, ensuring they will have maximal conservation impact. This project will contribute to the training of one graduate and several undergraduate students and foster cross-disciplinary training among the disciplines of natural resources, geography, and computer science. Spatial tools developed in this project and their application in conservation management will also be incorporated into undergraduate and graduate curricula.