Recovery is RELATED: Restoring Ecosystems by Linking Aquatic and Terrestrial Ecological Dynamics

Boreal regions hold upwards of 60% of the planet's freshwater, an essential ingredient for all life. But human activities, such as climate and land use change, are dramatically altering these landscapes and threatening the delivery of key services provided by aquatic ecosystems, such as clean drinking water and healthy 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 restoration attempts 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, proving the adage that "clean water is a forest product".

Any factor that changes the quality and quantity of organic matter input into freshwater from their surrounding catchments will clearly influence the delivery of aquatic ecosystem services. Fire, forest pests, and resource development, such as mining and logging, are emerging disturbances that are transforming boreal regions, but little is known as to how they will change long-term cycling of nutrients from terrestrial vegetation into aquatic ecosystems. A new watershed-level science that integrates the management of forestry and water resources is clearly needed to inform decision makers of the actions needed to conserve freshwater supplies by linking actions on land to processes in water.

Our research will test whether the productivity of aquatic food webs increases with the quantity and quality of terrestrial organic matter under different climate scenarios. We will also answer whether disturbances on land that remove plant biomass and change the quality of plant litter will dampen the productivity of freshwater plants and animals. Our approach will be to create 96 artificial ecosystems in a common lake environment and expose sites to different quantities and qualities of organic matter. We will measure the responses of microbial, algal, and grazer communities using cutting-edge technologies such as next-generation DNA sequencing. We will also plant tagged individuals of a sedentary mussel species closely-related to economically important taxa within each site and monitor their long-term growth and survival. The ultimate goal of this work is to develop a spatially-explicit, dynamical watershed-level simulation model. We want to answer the question if X% of habitat is consumed by fire or insect outbreaks, then food stocks for fish will change by Y%.

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. For example, the EU has developed legislation to protect freshwater but this ignores the effects of land use practices on lake water quality and biota. The future of extensive forestry plantations and pastures surrounding many socio-economically important watersheds in Britain are also being debated as the EU begins reforming the Common Agricultural Policy. We aim to show that any changes in land use must consider how energy in the form of organic matter is dispersed to aquatic ecosystems and supports their productivity. Finally, this project will have many applications for improving regional land use planning and management, as well as restoring environmentally damaged landscapes. We will work closely with partners in the mining industry and government to inform them of the best practices for re-vegetating degraded watersheds.

This project will quantify the effects of terrestrial organic matter on aquatic food webs under different climate scenarios, and develop decision support tools that will allow society to conserve freshwater resources impacted by global change. In addition to benefiting academic communities by advancing important scientific questions, such as those around the ecological function of different types of dissolved organic matter 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 our letters of support, 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, such as regional governments and multinational mining companies.

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. Recent work from a 9-year study in one of the most historically damaged landscapes in the world - Sudbury, Canada - has shown that controlling pollution alone cannot entirely restore or 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, we will benefit our Project Partners from industry and government by improving environmental sustainability, protection and impact reduction. We will also inform watershed management at an international level 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 industry, government, and the public that may wish to hear the outcomes of our project will be engaged through one-day workshops in Canada and the UK. In addition to the primary end-users in Canada with whom we are already collaborating, 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. Our research team brings extensive experience in knowledge transfer and end-user engagement, and we expect that by influencing land managers we will contribute towards evidence-based policy and end users will benefit from increases in the effectiveness of environmental policy and sustainability. Our work may also benefit governments by contributing towards local, regional, national, and international legislation. For example, the EU is preparing to review the effectiveness of the Water Framework Directive, so there is the potential to inform many governments about the need for broad watershed-level perspectives when enacting laws for protecting and restoring freshwater ecosystems.

The aquaculture industry is a another potential end user that may benefit with increased wealth creation and economic prosperity. One of our key study species - mussels - are heavily cultivated. We will encourage aquaculture companies to join our engagement workshop and visit our website for publications describing how terrestrial organic matter subsidies may improve the productivity of mussels.

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. By working closely with North America's only science communication programme, we will develop a series of short, professionally produced films that will be freely hosted and actively promoted online.