DISSERTATION RESEARCH: Consequences of habitat fragmentation for biodiversity and invasive species

该项目研究了生境碎片化(斑块)对本地植物多样性和非本地入侵草传播的直接和间接影响。片断化一直很难研究，因为它通常与栖息地丧失同时发生。该项目利用得克萨斯州中部稀树草原和林地的自然斑块来研究与栖息地丧失的影响分开的碎片化的影响。理论预测，碎片化和外来物种入侵都会降低物种多样性。一些模型表明，碎片化可能直接限制扩散能力有限的入侵植物的传播，但通过减少多样性间接促进入侵植物的建立。这些假设将得到检验。该项目将结合航空照片分析、实地观察、种子传播测量和多样性实验操作，以量化本地生物多样性、入侵草地的存在和传播以及栖息地碎片化之间的关系。碎片化和入侵物种的传播是对生物多样性的两个主要威胁。这项研究将检验关于这些过程的理论预测，并为景观结构的管理提供见解，以保护生物多样性。这笔助学金将资助一名研究生，并为几名本科生提供研究经验。

This project examines both the direct and indirect effects of habitat fragmentation (patchiness) on native plant diversity and the spread of a non-native invasive grass. Fragmentation has been difficult to study because it is usually occurs at the same time as habitat loss. This project takes advantage of the natural patchiness of central Texas savannas and woodlands to study the effects of fragmentation separate from the effects of habitat loss. Theory predicts that both fragmentation and invasive non-native species will reduce species diversity. Some models suggest fragmentation may directly limit the spread of invasive plants with limited dispersal ability, but indirectly facilitate their establishment by reducing diversity. These hypotheses will be tested. The project will combine analysis of aerial photographs, field observations, measurements of seed dispersal, and experimental manipulation of diversity to quantify the relationships among native biodiversity, the presence and spread of an invasive grass, and habitat fragmentation. Fragmentation and the spread of invasive species are two of the leading threats to biological diversity. This research will test theoretical predictions about these processes and provide insights for the management of landscape structure to preserve biodiversity. The grant will support a graduate student and provide research experience for several undergraduate students.