Dissertation Research: Can Enrichment of Micronutrients Help Restore Biological Soil Crusts to Desertified Landscapes?

在世界干旱地区，土壤表面覆盖着生物土壤结皮，这些结皮可以防止侵蚀，创造和保持土壤肥力，并影响水在景观上的流动和保留。生物土壤结皮可以被认为是生态系统功能的一个大“包”，它很容易由于广泛的表面干扰而丢失。以往的研究表明，提高土壤中微量元素的有效性可能会促进退化土壤结皮的恢复。为了验证这一假设，将进行两个实验：一个集中在温室中生长的一种关键的地壳地衣物种，另一个集中在野外的整个地壳群落。将监测不同肥料添加后结皮生物的反应，包括微量元素锌和锰的处理。一种新的涉及脂肪酸的生化技术将被开发用于测量生物土壤结皮的状态。最后，将使用统计建模方法检查五个现有的大规模数据集，以检验微量营养素限制北美多个干旱地区生物土壤结皮的假设。荒漠化对全球约20%的人口产生了不利影响，迫切需要新的防治手段。健康的土壤是陆地生态系统的基础。希望通过寻找促进生物结皮恢复的方法，可以恢复退化的干旱生态系统的功能，找到减缓沙漠化的方法。

In the dry regions of the world, the soil surface is covered by biological soil crusts which prevent erosion, create and maintain soil fertility, and influence where water moves and is retained on the landscape. Biological soil crusts can be thought of as a large 'package' of ecosystem function that is easily lost due to widespread surface disturbances. Previous studies indicate that greater availability of micronutrients in the soils may promote recovery of degraded soil crusts. To test this hypothesis, two experiments will be conducted: one focusing on a key crust lichen species grown in a greenhouse, the other focusing on the whole crust community in the field. Response of crust organisms will be monitored following various fertilizer additions, including manipulations of the micronutrients Zn and Mn. A new biochemical technique involving fatty acids will be developed to measure the status of biological soil crusts. Finally, five existing large-scale datasets will be examined using a statistical modeling approach to test the hypothesis that micronutrients limit biological soil crusts in multiple arid regions of North America. Desertification adversely impacts ~20% of the Earth's population, and new tools to combat it are desperately needed. Healthy soils are the foundation of terrestrial ecosystems. It is hoped that by finding ways to promote recovery of biological soil crusts, we can restore function to degraded arid ecosystems and find ways to slow desertification.