The role of land use change in the decline and recovery of coral reefs

由于气候变化影响的加速，珊瑚生存的窗口正在迅速关闭，迫切需要确定和实施短期解决办法，以遏制珊瑚的衰退和促进珊瑚的恢复。这项不发达战略的一个重要组成部分是减少危害珊瑚的陆上污染投入。该项目调查过去和现在陆基污染对珊瑚礁生态系统健康的影响，并评估改善土地利用以提高珊瑚礁对气候变化适应能力的潜力。为了解决缺乏珊瑚礁水质监测的问题，这项研究将珊瑚礁化石记录的数据与来自卫星图像的沿海土地利用变化的历史和当前数据结合起来，以将过去40年来人类对陆地的变化与珊瑚礁水质和珊瑚健康的变化联系起来。这一方法提供了时间尺度上的数据，可导致对土地变化对珊瑚礁的长期影响有新的了解和监测。这项研究利用与当地珊瑚礁保护组织和研究机构建立的伙伴关系，向当地珊瑚礁管理者提供了一系列通过改善土地管理来提高珊瑚礁健康的潜在方案。该项目还为学生提供传统上独立的古生态学、珊瑚礁生态学、环境地球化学和地理学等领域的跨学科培训。许多地区的珊瑚礁受到一系列环境和社会因素的负面影响。在过去的50年里，由于气候变化和当地人类影响的累积影响，珊瑚礁失去了一半以上的栖息地，其中包括捕鱼、引入入侵物种、土地利用和土地覆盖的变化以及相关的陆基污染。这些下降威胁到珊瑚礁的可持续性和珊瑚礁为数百万人提供的关键生态系统服务。尽管人们普遍怀疑珊瑚减少与珊瑚礁水质下降有关，但很难量化土地利用与土地覆盖变化、珊瑚礁水质变化和珊瑚衰退之间的联系，因为：(1)陆地系统科学界对陆上活动及其对沿海海洋系统的相关社会生态影响之间的联系研究不足；(2)缺乏关于人类和珊瑚礁生态系统动态的长期数据。该项目将恢复长期珊瑚礁水质和生态系统健康的古生态和地球化学技术与遥感数据的地理空间分析相结合，以追踪加勒比海沿岸流域的长期人为变化。这种方法解决了珊瑚礁管理和保护的三个关键问题：(1)过去40年来，与人为土地利用转换相关的陆地系统动态如何影响珊瑚礁的水质？(2)受陆基污染和径流影响的珊瑚礁水质的变化如何影响珊瑚礁在百年和千年的时间尺度上的健康和弹性？(3)土地利用管理的改善对未来珊瑚礁健康的预测影响是什么？该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，认为值得支持。

As the window for coral survival is quickly closing due to accelerating climate change impacts, there is an urgent need to identify and implement near-term solutions to stem coral declines and promote coral recovery. One essential component of this strategy that is underdeveloped is the reduction of land-based pollution inputs that harm corals. This project investigates the past and present impacts of land-based pollution on the health of coral reef ecosystems and assesses the potential for improved land use to increase reef resilience to climate change. To address the lack of reef water quality monitoring, this study combines data from the reef fossil record with historical and current data on coastal land use change from satellite imagery to link human alteration on land over the past 40 years with changes in reef water quality and coral health. This approach provides data at temporal scales that can lead to new understanding and monitoring of the long-term impacts of land alteration on coral reefs. This study uses established partnerships with local reef conservation organizations and research institutions to provide local reef managers with a range of potential scenarios for increasing coral reef health via improved land management. This project also provides students with interdisciplinary training in the traditionally separate fields of paleoecology, coral reef ecology, environmental geochemistry, and geography.Coral reefs in many regions are negatively impacted by a range of environmental and social factors. Over the past 50 years reefs have lost over half of their habitat forming corals due to the cumulative effects of climate change and local human impacts including fishing, introduction of invasive species, land use and land cover change, and associated land-based pollution. These declines threaten reef persistence and the critical ecosystem services reefs provide to millions of people. Although it is widely suspected that coral loss is associated with declining reef water quality, it has been difficult to quantify the link between land use and land cover change, reef water quality change, and coral declines because (1) the linkages between land-based activities and associated social-ecological impacts on coastal marine systems have been under-studied within the land system science community and (2) there is a lack of long-term data on human and reef ecosystem dynamics. This project combines paleoecological and geochemical techniques for reconstructing long-term reef water quality and ecosystem health with geospatial analyses of remote sensing data to track long-term anthropogenic change to Caribbean coastal watersheds. This approach addresses three key questions for reef management and conservation: (1) How have land system dynamics associated with human-induced land use conversion affected reef water quality over the past 40 years? (2) How has changing reef water quality, impacted by land-based pollution and runoff, affected coral reef health and resilience over centennial and millennial time scales? (3) What are the projected impacts of improved land use management on future coral reef health?This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.