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

在世界干旱地区，土壤表面被生物土壤结皮覆盖，生物结皮防止侵蚀，创造和保持土壤肥力，并影响水在地形上的流动和保持。生物土壤结皮可以被认为是生态系统功能的一个大“包”，很容易因广泛的地表干扰而丧失。以往的研究表明，在土壤中增加微量营养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：一个关注在温室中生长的关键结皮地衣物种，另一个关注田间的整个结皮群落。在添加各种肥料后，将监测结皮生物的反应，包括对微量营养素锌和锰的处理。将开发一种新的涉及脂肪酸的生化技术来测量生物土壤结皮的状态。最后，将使用统计建模方法检查现有的五个大规模数据集，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。荒漠化对地球上约20%的人口造成了不利影响，迫切需要新的工具来对抗它。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土壤结皮恢复的方法，恢复退化的干旱生态系统的功能，找到减缓荒漠化的方法。

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.