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

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.

This project will test how watershed characteristics control the use of terrestrial resources in aquatic food webs across the world's lake hotspots. In addition to benefiting academic communities by advancing important scientific questions, such as those around the levels of terrestrial support of aquatic consumers, and generating data that will be available to other researchers, our work has timely relevance to the formulation of policy associated with freshwater management in the EU and internationally. As seen in the Letter of Support from the European Commission, our project has been carefully designed from inception to set objectives that address the needs of end-users that must manage and restore water bodies.

Defra has recently (9 Apr 2013) adopted a policy to improve the quality of water-bodies, as only 27% of those in England are classified as being of "good status" under EU standards. However, most of their actions are focused on reducing agricultural, urban, and chemical pollution. A recent article published in the journal Nature (30 Sep 2010) has shown that controlling pollution alone cannot entirely improve the functioning of freshwater ecosystems. Rather, the quantity and quality of organic matter exported from soils may control the downstream benefits within receiving waters. The potential to predict how terrestrial and aquatic ecosystems interact remains a key need for many end-user communities. Through close collaboration in this and other current NERC-funded research, we will benefit government and industry by generating guidelines to improve environmental sustainability and protection. We will also inform watershed management at an international level with our cross-continental data synthesis and address the following issues of high priority for NERC: sustainable use of natural resources; biodiversity; and environment, pollution and human health.

Other users in government, industry, and the public that may wish to hear the outcomes of our project will be engaged through a symposium organized at a major scientific meeting and workshops held in North America and Europe associated with our other funded research. The key attendee at the symposium associated with this project will be the European Commission Directorate-General for the Environment, who have been tasked with aiding the implementation and reporting on the Water Framework Directive (WFD). The WFD mandates EU member countries to protect and restore freshwater ecosystems, but it conspicuously lacks an explicit focus upon how land itself influences water. As the First Management Cycle of the WFD ends in 2015, there is the potential for our project to inform decision makers from many different nations of the need for much broader watershed-level perspectives when enacting local, regional, national, and international laws for protecting freshwater ecosystems. We will feed the results of this project directly to the European Commission to help guide these outcomes. Additionally, interested users in the UK will include Natural England, Defra/Cefas, the Forestry Commission, JNCC, local councils, and local naturalist groups, as well as resource industries. They will benefit from increases in the effectiveness of environmental policy and sustainability.

Finally, we expect that the general public will be interested in the outcomes of our project and benefit from an increased awareness and understanding of science. We will engage with them through traditional media facilitated by the Cambridge University Media Relations team and new social media tools, such as blogs and Twitter.