EAPSI: Linking Grazing Management and Gully Erosion to Water Quality in the Great Barrier Reef

澳大利亚昆士兰海岸外的大堡礁（GBR）是世界上最大、生物多样性最丰富的珊瑚礁系统，但它的健康和生存受到许多外部因素的威胁。该项目旨在通过将长期放牧管理与Burdekin盆地沉积物输出和侵蚀的影响联系起来，调查GBR泻湖水质下降的威胁。虽然土地覆盖对沟壑侵蚀的影响已经通过小规模的、基于地块的实验得到了很好的记录，但对历史放牧管理对沟壑活动和扩张速度的长期影响知之甚少。这项研究将与澳大利亚堪培拉联邦科学与工业研究组织（CSIRO）的沟壑侵蚀专家斯科特·威尔金森博士合作进行。通过比较历史记录和植被调查，这项研究将提供高地牧场沟壑侵蚀的定量分析，帮助CSIRO和澳大利亚政府努力改善水质和保护大堡礁。海水温度升高、海洋酸化和GBR泻湖水质下降对GBR造成了严重的退化和死亡。CSIRO将进口到GBR泻湖的所有细沉积物的40%归因于集水区流域的牧场沟壑侵蚀。侵蚀与土地覆盖直接相关；GBR的研究表明，植被覆盖增加5-15%可减少35-60%的泥沙侵蚀，从而减少产沙量，改善GBR泻湖的水质。然而，人们对放牧管理和沟壑活动的长期影响知之甚少。对于特定的易发生沟壑的土壤类型，本项目将通过比较植被覆盖的历史遥感图像和沟壑稳定性调查，评估不同放牧管理和放养率对沟壑稳定性的长期影响。本研究项目旨在提供放牧和侵蚀的定量评估，并确定标准，以确定极易受到过度泥沙输出的地区，以便优先进行预防性管理。该奖项由美国国家科学基金会和澳大利亚科学院共同资助，隶属于东亚和太平洋暑期研究所项目，支持一名美国研究生进行暑期研究。

The Great Barrier Reef (GBR) off the coast of Queensland, Australia, is the world's largest and most biodiverse coral reef system, but its health and survival is threatened by a number of external factors. This project aims to investigate one threat--decreased water quality in the GBR lagoon--by linking the impacts of long-term grazing management with sediment export and erosion in the Burdekin Basin. Though the impacts of land-cover on gully erosion have been well documented through small-scale, plot-based experiments, there is little knowledge of the long-term effects of historical grazing management to gully activity and rate of expansion. This research will be conducted in collaboration with Dr. Scott Wilkinson, an expert in gully erosion, at the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Canberra, Australia. By comparing historical records and vegetation surveys, this research will provide a quantitative analysis of gully erosion in upland rangelands, aiding CSIRO and the Australian government in the effort to improve water quality and preserve the Great Barrier Reef. Seawater temperature rise, ocean acidification, and decreased water quality in the GBR lagoon are causing considerable degradation and mortality to the GBR. CSIRO attributes 40% of all fine sediment imported to the GBR lagoon to rangeland gully erosion in the catchment basins. Erosion is directly linked to land-cover; studies in the GBR have shown that a 5-15% increase in vegetation cover can reduce sediment erosion by 35-60%, thereby decreasing sediment yield and improving water quality in the GBR lagoon. However, there is little knowledge about the long-term effects of grazing management and gully activity. For specific gully-prone soil types, this project will evaluate the long-term effects of different grazing management and stocking rates on gully stability by comparing historical remote sensing imagery of vegetation cover to surveys of gully stability at 10-20 different properties. This research project aims to provide a quantitative assessment of grazing and erosion and determine criteria to identify zones exceedingly vulnerable to over-proportioned sediment export for priority preventative management. This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Australian Academy of Science.