User:Mjwatcho/Wetland restoration

Wetland Restoration

Restoration and restoration ecologists intend to return wetlands to their natural trajectory by aiding directly with the natural processes of the ecosystem. These direct methods vary with respect to the degree of physical manipulation of the natural environment and each are associated with different levels of restoration. Restoration is needed after disturbance or perturbation of a wetland. Disturbances include exogenous factors such as flooding or drought. Other external damage may be anthropogenic disturbance caused by clear-cut harvesting of trees, oil and gas extraction, poorly defined infrastructure installation, over grazing of livestock, ill considered recreational activities, alteration of wetlands including dredging, draining, and filling, and other negative human impacts. Disturbance puts different levels of stress on an environment depending on the type and duration of disturbance. There is no one way to restore a wetland and the level of restoration required will be based on the level of disturbance although, each method of restoration does require preparation and administration.

Levels of Restoration

1. Prescribed Natural Regeneration

   There are no biophysical manipulation and the ecosystem is left to recover based on the process of succession alone. The focus of this method is to eliminate and prevent further disturbance from occurring. In order for this type of restoration to be effective and successful there must be prior research done to understand the probability that the wetland will recover with this method. Otherwise, some biophysical manipulation may be required to enhance the rate of succession to an acceptable level determined by the project managers and ecologists. This is likely to be the first method of approach for the lowest level of disturbance being that it is the least intrusive and least costly.

2. Assisted Natural Regeneration

   There are some biophysical manipulations however they are non-intrusive. Example methods that are not limited to wetlands include prescribed burns to small areas, promotion of site specific soil microbiota and plant growth using nucleation planting whereby plants radiate from a initial planting site, and promotion of niche diversity or increasing the range of niches to promote use by a variety of different species. These methods can make it easier for the natural species to flourish by removing competition from their environment and can speed up the process of succession.

3. Partial Reconstruction

   Here there is a mix between natural regeneration and manipulated environmental control. These manipulations may require some engineering and more invasive biophysical manipulation including ripping of subsoil, agrichemical applications such as herbicides and insecticides, laying of mulch, mechanical seed dispersal, and tree planting on a large scale. In these circumstances the wetland is impaired and without human assistance it would not recover within an acceptable period of time determine by ecologists. Again these methods of restoration will have to be considered on a site by site basis as each site will require a different approach based on levels of disturbance and ecosystem dynamics.

4. Complete Reconstruction

   The most expensive and intrusive method of reconstruction requiring engineering and ground up reconstruction. Because there is a redesign of the entire ecosystem it is important that the natural trajectory of the ecosystem be considered and that the plant species will eventually return the ecosystem towards it's natural trajectory.

Factors influencing selected approach may include

• Budget
• Time scale limitations
• Project goals
• Level of disturbance
• Landscape and ecological constraints
• Political and administrative agendas
• Socioeconomic priorities

Disturbance Levels

Minor Disturbance

Stress that maintains ecosystem integrity.

Moderate Disturbance

Ecosystem integrity is damaged but can recover in time without assistance.

Impairment or Sever Disturbance

Human intervention may be needed in order for ecosystem to recover.

Legislation

International Efforts

• Ramsar Convention
• North American Waterfowl Management Plan

Canadian National Efforts

Natural Subregions

Central Mixedwood

The Central Mixedwood natural subregion is the largest natural subregion of Alberta. Comprising of mixed deciduous tree stands in later succession stages indicator plants include balsam poplar and red-osier dogwood in the moister sites.

Dry Mixedwood

The Dry Mixedwood natural subregion is the warmest Boreal natural subregion and is the second largest natural subregion in Alberta.