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

澳大利亚昆士兰州海岸外的大堡礁（GBR）是世界上最大和生物多样性最丰富的珊瑚礁系统，但其健康和生存受到一些外部因素的威胁。该项目旨在调查一个威胁-GBR泻湖水质下降-将长期放牧管理的影响与Burdekin盆地的沉积物输出和侵蚀联系起来。虽然土地覆被对沟蚀的影响已经通过小规模的、以地块为基础的实验得到了很好的证明，但对历史上放牧管理对沟蚀活动和扩展速度的长期影响却知之甚少。这项研究将与位于澳大利亚堪培拉的联邦科学和工业研究组织的沟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。海水温度上升、海洋酸化和GBR泻湖水质下降正在导致GBR的严重退化和死亡。CSIRO将输入GBR泻湖的所有细沉积物的40%归因于集水盆地中的牧场沟壑侵蚀。侵蚀与土地覆盖直接相关;在GBR的研究表明，植被覆盖增加5-15%可以减少35- 60%的泥沙侵蚀，从而减少泥沙产量并改善GBR泻湖的水质。然而，人们对放牧管理和冲沟活动的长期影响知之甚少。对于易形成沟壑的特定土壤类型，本项目将通过比较植被覆盖的历史遥感图像与10-20种不同性质的沟壑稳定性调查，评估不同放牧管理和放牧率对沟壑稳定性的长期影响。该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沉积物输出影响的地区，以便进行优先预防性管理。该奖项是东亚和太平洋夏季研究所计划的一部分，由NSF和澳大利亚科学院共同资助，支持美国研究生的夏季研究。

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.