Conservation, restoration and effects of climate change on wetlands

1. Conservation, restoration and effects of climate change on wetlands Dr Debbie Chapman School of Biological, Earth and Environmental Sciences University College Cork, Ireland curriculumin natural environmental science, vol. 2, 2010

2. Value of wetlands • Essential habitat for rare or endangered species • Commercial fisheries • Recreational fisheries • Natural improvements to waterquality • Overwintering habitat for waterfowl • Reducing erosion and buffering storm impacts (coastal wetlands) • Mitigating impacts of sea level rise (coastal wetlands)

3. Wetland loss: examples UK East Anglian Fennland • 17th Century: 3,380 km2 • Present time: about 10 km2 USA • 16th Century: 900,000 km2 • Present time: 400,000 km2 (California and Ohio lost 91% and 90% respectively)

4. Reasons for loss • Natural succession (usually matched by creation of new wetlands) • Drainage and reclamation to create agricultural land • Lowering of water table through ground-water abstraction • Interference with hydrological regimes (e.g. impoundment of rivers, coastal development) Tree stumps in the reservoir created by impoundment of a river for a hydrolectiricty scheme in Southern Ireland

5. Degradation of coastal marshes Sea level rise and land subsidence need to be matched by sediment and organic matter accumulation • Human activities are leading toan imbalance by decreasingsediment accretion • Creation of barriers tolandward marsh growth,e.g. roads, sea walls • Harvesting of trees • Disturbance of hydrologicalregimes A causeway has separated this wetland from the coast and created an artificial lagoon of less value to waterfowl

6. Climate change projections • Global mean temperature change from 1990: 1.4–5.8 °C • Sea level rise: 10–90 cm by year 2100 • Change in frequency and intensity of extreme climate events, e.g. increase in number of hot days, fewer cold days, more frequent intense downpours, increased frequency and intensity of floods and droughts • The greatest changes in temperature and precipitation likely to occur in the northern hemisphere

7. Possible impacts from projected extreme climate events

8. Climate impacts on wetlands • It is likely that climate change impacts on water resources over the next 20 years will be small relative to the impacts of other changes • Most likely impact on wetlands will be through alteration of hydrological regimes and occurrence of extreme weather events

9. Climate change: Inland wetlands • Change of plant communities • Invasion or expansion of alien species • Tropical wetland floodplainsreplaced with salt waterhabitats and salttolerant species • Loss of feeding/breedinggrounds for birds and fish • Interrupted migrationroutes for birds Regular tidal inundation leaves insufficient feeding area exposed for the birds

10. Climate change: Coastal wetlands • When combined with other human-induced losses, coastal wetland loss could be as high as 70% • Vulnerable wetlands are low-lying deltas and coastal plains – estuaries, lagoons, salt-marshes, mangroves • Climate change will lead to: • Landward intrusion of seawater • Coastal inundation and stormsurge flooding • Inland and upstream salinityintrusion • Changes in ecosystem structurecaused by changes in temperatureand rainfall patterns Attempts to restrict coastal erosion have been abandoned at this beach in Western Ireland

11. Projected impacts of climate change in Europe: inland wetlands • Increased winter rainfall and river flows, leading to flooding • Decreased summer flows and higher temperatures leading to low dissolved O2 and poor water quality • Increased fish productivityand a shift towards cyprinidand percid fish • Peatlands will expand north-wards, possibly replacingtundra • Loss of isolated depressionalwetlands may affect migratoryand breeding bird populations Evidence of a breeding population of carp in a shallow lake in Ireland

12. Projected impacts of climate change in Europe: coastal wetlands Mediterranean and Baltic deltas, estuaries and salt marshes particularly at risk from sea level rise (extent of development on coasts restricts options for conservation/restoration) • Possible loss of salt marshes andintertidal estuarine zones will reduce habitats for wildlife,fish and migratory birds • Distributions of some shorebirdsalready occurring due tochanges in regional temperaturepatterns • Rhône, Po and Elbe deltassusceptible due to existing reducedsediment loads Erosion of rare estuarine peat saltmarsh in the West of Ireland

13. Conservation and restoration • Conservation - long-term preservation and protection of the functions and values of wetlands • Restoration – returning a degraded wetland (rehabilitation) or former wetland (re-establishment) to a pre-existing condition or as close to that condition as possible

14. Conservation of coastal wetlands for impacts of climate change • Manage landward reinstatement of coastal wetland habitats through removal of sea defense structures • Design multiple-use reserves and protected areas which incorporate corridors that would allow for migration of organisms as a response to climate change • Expand aquaculture that could relieve stress on natural fisheries • Integrated resource management

15. Restoration: Passive • Removal of cause of degradation and allow natural regeneration (e.g. removal of grazing livestock) • Not always practicable (close access to water and wetland species essential) • Low cost • Likely that the resultant wetland will resemble the surrounding environment

16. Restoration: Active • Appropriate when wetland is severely degraded • Examples: weirs and culverts, intensive planting, invasive species control, substrate creation • Considerable design workneeded • Construction costs may be high The London Wetland Centre: Wetland restoration in the suburbs on London to create a bird reserve http://www.wwt.org.uk/visit-us/london

17. Restoration: traditional versus soft engineering solutions • Traditional “hard” engineering solutions replace natural ecosystem functions with human-designed structures, e.g. concrete embankments to prevent erosion • “Soft” solutions include planting native species such as willows, log banks and geotextile materials Concrete embankments Restoration of banks along RiverThames with native vegetation

18. Restoration: important factors to consider • Hydrology • Topography and geology • Soil type • Vegetation and animal life • Land ownership • Stakeholder involvement

19. Examples of wetland problems and possible remediation methods

20. Restoration: usefulness and feasibility • Will there be environmental benefits (e.g. improved water quantity, reduced eutrophication, biodiversity conservation, flood control)? • What is the cost effectiveness of the proposed rehabilitation? • What options, advantages or disadvantages will the restored area provide for local people and the region? • What is the present and possible future ecological status of the project? • What is the status of the area in terms of present land use? • What are the main socio-economic constraints? • What are the main technical constraints? http://www.ramsar.org/key_guide_restoration_e.htm

21. Sources of information • Ramsar Convention Secretariat, 2007 Inventory, assessment, and monitoring: An Integrated Framework for wetland inventory, assessment, and monitoring. Ramsar handbooks for the wise use of wetlands, 3rd edition, vol. 11. Ramsar Convention Secretariat, Gland, Switzerland. • Ramsar Convention 2002 Climate change and wetlands: impacts, adaptation and mitigation. Ramsar COP8 Doc 11: Climate Change and Wetlands. • Interagency Workgroup on Wetland Restoration (IWWR) 2003 An Introduction and User’s Guide to Wetland Restoration, Creation and Enhancement. US Environmental Protection Agency, Office of Water, 95 pp. http://www.epa.gov/owow/wetlands/pdf/restdocfinal.pdf • USEPA, 2000 Principles for the Ecological Restoration of Aquatic Resources. EPA841-F-00-003. Office of Water (4501F), United States Environmental Protection Agency, Washington, DC. 4 pp.