DISSERTATION RESEARCH: How Land Cover and Landscape Connectivity Interact to Determine Species Ranges

寻找协调人类和野生动物栖息地需求的方法对于保护物种多样性具有重要意义。本研究的目的是研究在人类主导的景观中，土地利用如何影响野生物种的发生。这些野生物种的“分布”取决于两种栖息地的可用性：种群可以生长和持续的栖息地，以及连接种群以允许分散的栖息地。土地利用的变化可以影响这两种类型的栖息地，但大多数研究只考虑了第一种类型。本研究的重点是栖息地连通性如何影响青蛙种群的生长和生存。在此过程中，它将为研究生和本科生提供研究培训。这项研究的结果将用于为小学生制作教育材料，他们将了解栖息地的连通性如何影响动物的扩散。调查人员将与迈阿密大学的海夫纳自然历史博物馆合作，创建一个展览，解释人类土地利用的模式如何影响野生动物。最后，本研究开发的方法可为物种管理计划提供依据。具体来说，这个项目的目标是测试景观连通性解释物种差异的假设。已实现的与潜在的分布，基于合适栖息地的可用性。使用蟋蟀蛙（Acris blanchardi）作为模型系统，研究人员将解决以下目标：(1)评估哪些土地利用和环境因素对生境适宜性最重要，并能预测物种存在；(2)确定目前的范围东部边缘以及实际蟋蟀蛙分布与适宜栖息地分布（潜在分布）之间是否存在差异；(3)评估从范围内部到边缘的景观连通性梯度是否可以解释已实现和潜在分布的差异。目标1和目标2将通过生态位建模和地面实况调查来解决。生态位模型将使用以前调查的存在数据，并包括气候和土地利用数据层。目标3将通过结合基于图论的景观连通性分析中的生态位模型结果来解决。将比较范围内、范围边缘和范围外的连通性。由于最近蟋蟀蛙范围边界的收缩和扩张，研究人员预测了当前范围之外的合适栖息地区域。在范围边界和范围外的低水平景观连通性被预测解释了为什么蟋蟀蛙无法占据它们的整个潜在范围。

Finding ways to reconcile the habitat needs of people with those of wildlife is of great importance for preservation of species diversity. The objective of this study is to examine how land-use in a human dominated landscape affects where wild species occur. These "distributions" of wild species depend on availability of two types of habitat: habitat where populations can grow and persist, and habitat that connects populations to allow for dispersal. Changes in land-use can affect both types of habitat, yet most research has considered just the first type. This study focuses on how habitat connectivity impacts the growth and survival of frog populations. In doing so, it will provide research training for graduate and undergraduate students. Findings from this study will be used to create educational materials for elementary school students, who will learn about how habitat connectivity affects animal dispersal. The investigators will collaborate with the Hefner Museum of Natural History at Miami University to create a display explaining how patterns of human land-use affect wildlife. Finally, the methodology developed for this study may provide the basis for species management plans.Specifically, the goal of this project is to test the hypothesis that landscape connectivity explains discrepancies in a species? realized versus potential distribution, based on availability of suitable habitat. Using cricket frogs (Acris blanchardi) as a model system, investigators will address the following aims: (1) assess which land-use and environmental factors are most important for habitat suitability and are predictive of species presence, (2) determine the current eastern edge of the range and whether there is a discrepancy between the actual cricket frog distribution and the distribution of suitable habitat (potential distribution), and (3) assess whether a gradient in landscape connectivity from the interior to edge of the range can explain differences in realized and potential distributions. Aims 1 and 2 will be addressed using ecological niche modeling and ground-truthing surveys. The niche model will use presence data from previous surveys and include both climatic and land-use data layers. Aim 3 will be addressed by incorporating niche model results in landscape connectivity analyses based on graph theory. Connectivity will be compared between the interior of the range, the range edge, and outside the range. Due to recent contraction and expansion of the cricket frog range boundary, investigators predict areas of suitable habitat outside the current range. Low levels of landscape connectivity at the range boundary and outside the range are predicted to explain why cricket frogs are unable to occupy their entire potential range.