Trade-off in ecosystem services of the Somerset Levels and Moors wetlands

It is widely recognized that healthy ecosystems can provide considerable benefits to people, including food, timber, freshwater, protection from floods and much of what we call quality of life. A global review of these ecosystem services carried out as part of the Millennium Ecosystem Assessment (MEA) provided a framework for national and local studies. Using the MEA approach, this paper reviews the ecosystem services provided by the Somerset Levels and Moors wetland system in southwest England. This wetland provides a series of important services that are beneficial locally, regionally and globally, including grazing for cattle, carbon sequestration, flood water storage, recreation and archaeology. Some services are synergistic and reinforcing; for example, maintaining wet conditions supports wetland bird life that maintains biological diversity, attracts tourists, protects archaeological artefacts and reduces CO2 emissions; raising water levels to or above the ground leads to net greenhouse gas uptake by the wetland. Other services are potentially conflicting, for example raising water levels may reduce potential flood water storage and increase methane emissions. Comparison of the services of the wetland with those of drier habitats reveals for example that carbon sequestration, bird habitat provision and hay production is greater in wetlands, whilst grazing quality may decline and plant diversity may be reduced in the short term and distributions of disease vectors may be altered by wetland restoration through raising water levels. Management decisions affecting wetlands may necessitate a trade-off of ecosystem services.