Case study: Isle of Wight

Purpose of wetland creation and restoration and expected results (protection vs. nourishment) Riparian ecosystems generally compose a minor proportion of surrounding areas, but typically are more structurally diverse and more productive in plant and animal biomass than adjacent upland areas. Riparian areas supply food, cover, and water (especially important in the arid regions) for a large diversity of animals, and serve as migration routes and forest connectors between habitats for a variety of wildlife, particularly ungulates and birds. Wetland generally occupy relatively small areas, and their occurrence along waterways makes them vulnerable to severe alteration caused by a variety of development activities. Impacts include expanding agriculture; channelization projects; reservoir and dam construction; heavy livestock grazing; road, bridge, and pipeline construction; flood control projects. Riparian ecosystems generally are more structurally diverse and more productive in terms of plant and animal biomass than surrounding areas. A number of difficulties are encountered when attempting to restore riparian zones to their original condition: (1) the historical condition of rivers might not be well known; (2) ecological means of returning to a known prior condition are not understood, nor is it certain that this is possible; and (3) presence of man-caused phenomena for long periods of time may genetically alter a species to the extent that restoration may affect it unfavorably. Success determinations would benefit from an investigation of various functions of riparian wetlands (including wildlife and fish habitat, hydrologic flow, erosion control, water quality improvement, and recreational use). Because riparian ecosystems often are relatively small areas and occur in conjunction with waterways, they are vulnerable to severe alteration. Wetlands throughout the World have been heavily impacted by man’s activities. Riparian ecosystem creation and restoration have been used as mitigation for project impacts from highway, bridge, and pipeline construction; water development; flood control channel modifications; industrial and residential development; agriculture; irrigation; livestock grazing; mining; and accidental habitat loss. Creation of a riparian ecosystem requires appropriate water supply and grading the topography to suitable elevations to support plantings of riparian vegetation. Restoration involves returning the ecosystem to pre-disturbance conditions and typically implies re-vegetation. Removing exotic vegetation or restoring water supplies to pre-disturbance level also may be involved.