DISSERTATION RESEARCH: How do species coexist under spatial variation across scales?

自然界是如何保持其惊人的多样性的，特别是在直接相互竞争的物种之间？理论预测，随着时间和空间的推移，物理环境的不断变化以及从一个尺度到另一个尺度的转变（从更小到更大的空间，从更短到更长的时间）可以解释物种共存。到目前为止，这一预测缺乏严格的实证检验。拟议的项目将使用多尺度的实地实验和基于实地数据的数学建模来检验这一假设，即较小规模的环境变化促进了索诺兰沙漠中入侵和本地沙漠冬季一年生植物之间的大规模共存。研究人员将结合联合收割机稳定同位素分析，航空照片和实地实验，以量化共存和维护生物多样性的关键机制。该项目将为科学家提供一个强有力的模型，以便对广泛的自然群落中的物种共存进行严格的经验测试。除了解决生态学中的一个基本问题外，该项目还将促进对生物入侵的动态性质的理解，突出入侵可能造成问题的条件。通过向土地管理者通报这些情况，该项目为管理入侵物种提供了切实可行的解决方案。该项目是亚利桑那大学和美国海军陆战队航空站尤马的合作，成果将与必须管理入侵物种的军事单位和政府机构分享。该项目还将培训四名本科生，向他们介绍科学发现的严谨和兴奋。

How does the natural world maintain its astonishing diversity, especially among species that directly compete with each other? Theory predicts that constant changes to the physical environment over time and space and the transition from one scale to another (smaller to larger space, shorter to longer time) can account for species coexistence. To date, this prediction lacks rigorous empirical tests. The proposed project will use multi-scale field experiments and mathematical modeling based on field data to test the hypothesis that smaller scale environmental variation promotes broad-scale coexistence between invasive and native desert winter annual plants in the Sonoran Desert. Researchers will combine stable isotope analysis, aerial photographs, and field experiments to quantify a key mechanism underlying coexistence and the maintenance of biodiversity. The project will provide a powerful model for scientists to conduct rigorous empirical tests on species coexistence across a broad spectrum of natural communities. Together with addressing a fundamental question in ecology, the project will foster an understanding of the dynamic nature of biological invasions, highlighting conditions under which an invasion is likely to cause problem. By informing land managers of those conditions, the project offers practical solutions to managing invasive species. The project is a collaboration between the University of Arizona and the US Marine Corps Air Station, Yuma, and results will be shared with military units and government agencies that must manage invasive species. This project will also train four undergraduate students, introducing them to the rigor and excitement of scientific discovery.