Watershed determinants of terrestrial resource use by aquatic organisms across the world's freshwater hotspots

北温带地区拥有地球上大部分的淡水，这是所有生命的基本成分。但是，土地利用变化等人为活动正在戏剧性地改变这些景观，并威胁到水生生态系统提供的关键服务的提供，例如生产性鱼类种群。当代的水产养护模式强调污染物的投入和水资源开发是水安全和生物多样性下降的原因，但如果这两个因素单独得到改善，这些模式就会失败。当地的流域越来越多地被视为水生生态系统的关键控制因素。这是由最近的一项发现刺激的，即从微生物到鱼类，通过水生食物网向上动员能量的途径依赖于源自陆地植被的有机物。换句话说，新的研究正在证明一句谚语，即鱼实际上是一种“森林产品”。任何改变从陆地输出到水中的有机物的质量和数量的因素都将影响水生生态系统服务的提供。例如，人类的土地利用做法和新出现的干扰，如火灾和森林病原体，将改变从陆地植被到水生生态系统的养分循环。但是，这些因素中哪一个是最重要的，并在不同的地理区域持续发挥作用，目前尚不清楚。确定这些驱动因素对于开发新的分水岭级别的淡水保护方法至关重要，这些方法将陆地上的行动与水中的过程联系起来。我们的研究将测试不同的分水岭特征如何控制世界湖泊丰富地区水生食物网中陆地资源的使用。我们将利用我们的发现来预测未来与全球变化相关的湖泊食物网的变化，并推荐保护淡水资源的更好做法。我们的方法将是将研究陆地-水生联系的领先国际研究人员聚集在一起，并合成超过175个湖泊的可用食物网测量数据。利用为每个研究湖泊提取的生物气候、植被、生物地球化学和土地利用数据，以及尖端的统计建模技术，我们将预测湖泊食物网的陆地驱动因素，并将它们与水生生物的生物量积累联系起来。这项研究的结果将通过展示陆地和水生生态系统之间的紧密联系，与英国和国际上关于淡水供应管理的政策高度相关。我们研究的一个特别重点是改进水框架指令(WFD)，这是一项旨在保护淡水的泛欧洲立法。我们希望利用我们的研究，通过与欧盟委员会在我们的项目结束时组织的知识交流研讨会来影响与WFD相关的政策。该项目还将在改善区域土地利用规划和管理以及恢复破坏环境的景观方面有许多应用。我们正在与采矿业和政府密切合作，开展由NERC资助的相关项目，并将利用该项目的成果，更好地向这些合作伙伴介绍恢复退化流域植被的最佳做法。

North temperate regions hold much of the planet's freshwater, an essential ingredient for all life. But anthropogenic activities, such as land-use change, are dramatically altering these landscapes and threatening the delivery of key services provided by aquatic ecosystems, such as productive fish populations. Contemporary paradigms of aquatic conservation have emphasized inputs of pollutants and water resource development as causes of declining water security and biodiversity, but are failing when these two factors alone are improved. Increasingly, local watersheds are seen as critical controls of aquatic ecosystems. This is spurred by the recent discovery that pathways of energy mobilization upwards through aquatic food webs from microbes to fish rely on organic matter originating from terrestrial vegetation. In other words, new research is proving the adage that fish are in fact a "forest product".Any factor that changes the quality and quantity of organic matter exported from land into water will influence the delivery of aquatic ecosystem services. For example, human land use practices and emerging disturbances, such as fire and forest pathogens, will change the cycling of nutrients from terrestrial vegetation into aquatic ecosystems. But which of these factors are most important and consistently operating across different geographic regions is unknown. Identifying these drivers is critical for developing new watershed-level approaches for conserving freshwater that link actions on land to processes in water.Our research will test how different watershed characteristics control the use of terrestrial resources in aquatic food webs across lake-rich regions of the world. We will use our findings to forecast future changes in lake food webs associated with global change and recommend better practices for conserving freshwater resources. Our approach will be to bring together the leading international researchers studying terrestrial-aquatic linkages and synthesize available food web measurements from over 175 lakes. Using bioclimatic, vegetation, biogeochemistry, and land-use data extracted for each study lake, alongside cutting-edge statistical modelling techniques, we will predict the terrestrial drivers of lake food webs and link them to biomass accumulation by aquatic organisms.Outcomes of this research will be highly relevant to the UK and international policy around managing freshwater supplies by demonstrating strong linkages between terrestrial and aquatic ecosystems. A particular focus of our research is improving the Water Framework Directive (WFD), a piece of pan-European legislation designed to protect freshwater. We hope to use our research to impact policy associated with the WFD by engaging with the European Commission in a knowledge exchange symposium that we are organizing at the conclusion of our project. This project will also have many applications for improving regional land use planning and management, as well as restoring environmentally damaged landscapes. We are working closely with partners in the mining industry and government in associated NERC-funded projects and will use the results of this project to better inform these partners of the best practices for re-vegetating degraded watersheds.