Considerations When Working Around Wetlands

Wetlands in Urban Areas

Although wetlands cannot function independently from surrounding land uses, even in heavily populated areas healthy wetlands can be successfully maintained and enjoyed. To minimize disturbances to vulnerable wetland areas on or near your property, it is beneficial to create or enlarge an adjacent upland habitat area with a buffer.

Consider letting as much as possible of the area close to the wetland return to its natural state. Letting it regenerate will provide a variety of native plants that are not only visually appealing, but more importantly, provide a diversity of habitat for many wildlife species. Buildings, cleared areas, lawns, and gardens should be as far away from wetlands as possible to minimize disturbance. Delay mowing upland areas until mid-July so that nesting waterfowl and other birds can rear young.

Since the balance of water in a wetland is critical, ensure that changes to the surrounding area do not cut a wetland off from its sources of water. Also, make sure that water draining off your property into the wetland is of good quality and does not contain pesticides, fertilizers, salt, or other pollutants.

Wetlands in urban areas provide many opportunities to experience nature and to appreciate wildlife. Excessive human use, however, can damage fragile wetland ecosystems. Keep in mind that your family pet may be a potential threat to wildlife species, particularly during sensitive nesting or breeding times.

Suggestions...

• Maintain natural vegetation in wetlands, nearby uplands and buffer areas. Leave dead trees standing and avoid mowing to the edge of wetlands.
• Restrict use of fertilizers and pesticides.
• Do not dump lawn cuttings and other garden waste in wetlands. Consider using a backyard composter instead.
• Birdhouses or nesting boxes suitable for wetland dependent cavity nesters may compensate for limited nesting cavities. Ensure that these are properly maintained and equipped with predator guards.
• Keep pets on a leash in wetland areas.
• If nearby wetlands are used for public recreation, limit the impacts of your activities and stay on established paths.

Wetlands in Rural Settings

It is possible to improve wetland areas while still meeting farm business objectives. Many wetland improvements can be done at relatively low cost, are eligible for financial assistance and can ultimately benefit agriculture.

Some agricultural practices may negatively impact nearby wetlands. For example, poorly designed water crossings and over cultivation can enhance soil erosion. Eroded soils can increase turbidity in water, damage vegetation, cover fish spawning areas, and damage wildlife and waterfowl habitat. Loss of soil cover can also decrease agricultural productivity. Further, improper use of pesticides and excessive fertilization can also affect water quality. It is advisable to establish or maintain buffers around wetlands and nearby uplands. As well as providing valuable wildlife habitat and corridors and protecting wetlands from surrounding land uses, buffers can filter some eroded soils, pesticides and fertilizers before they reach the wetland. Buffers further benefit farmers by sheltering crops, providing windbreaks, reducing soil erosion, and protecting livestock.

A buffer of trees between the farm field and marsh protects the wetland. Gary McCullough

If possible, agricultural drains should be maintained when flows are low. Try to avoid times during spring and autumn that are critical for bird nesting or fish spawning. Keeping soil on the land is one of the best ways of reducing the need for drain maintenance. Planting and maintaining vegetation along drain banks will improve bank stability.

Although many wetland areas have been converted to agricultural uses, these may be difficult, unproductive, or unprofitable to farm. In some situations there may be more value in restoring wetlands to their natural state. Further information is available from the Ontario Ministry of Agriculture, Food and Rural Affairs in the Best Management Practices - Fish and Wildlife Habitat Management booklet.

Suggestions...

• Restrict or eliminate livestock access to sensitive wetlands through the use of fencing, or by densely planting selected trees and shrubs to form a barrier. Living fences are attractive and offer cover and habitat for many species of birds and other wildlife.
• Establish or maintain buffers around wetlands and do not cultivate or mow right to the edge.
• Consider installing alternative watering devices for livestock to limit access to streams and wetlands. The benefits to water quality and livestock health are well worth the relatively low cost investment.
• Install properly designed water crossings, using only recommended materials such as concrete culverts and gravel. Asphalt paving or old metal drums should not be used in or near the water. Permits may be required from the Ontario Ministry of Natural Resources for construction of water crossings.
• Use conservation tillage techniques and grazing management systems.
• Delay haying and install flushing bars on tractors to protect ground nesting birds from injury.

Water Diversion and Control

Presence of water throughout much of the year is the most critical factor in maintaining a wetland. Changes to water depth and length of wet or dry conditions may have profound effects on wetland function. Apart from destroying habitat, draining wetland areas lowers the water table, and can increase downstream erosion and flooding which can affect other landowners.

Water level control may benefit wetlands. Best Management Practices - Fish and Wildlife Habitat Management

The use of water level control structures may be beneficial to wetlands in certain circumstances. Occasional drawdowns help to recirculate nutrients and provide temporary mudflats for shorebirds. Maintaining constant water levels during winter benefits muskrat, fish and amphibian populations. Increased flooding to a marsh may create open water areas which encourages the growth of a diversity of aquatic plants and provides habitat for waterfowl and other wildlife. These activities may also provide ideal conditions for invasion by exotic species such as purple loosestrife, so caution is warranted. Since each wetland is unique, changes should not be made without expert guidance.

Additional information on farm water management can be found in the following Best Management Practices (BMP) booklets available from the Ontario Ministry of Agriculture, Food and Rural Affairs: Water Management; Fish and Wildlife Habitat Management; and, Irrigation Management. Please note that permits are required from the Ontario Ministry of Natural Resources for stream diversions, enclosures, dams, weirs, channelization, and pond creation.

Suggestions...

• Maintain the existing balance of water in a wetland.
• Install water level control structures, such as berms, low-flow weirs, dams, and beaver bafflers in appropriate situations to ensure consistent water levels or periods of drawdown.
• Before making any changes, seek advice from your local Stewardship Council, Conservation Authority, Ontario Ministry of Natural Resources, or one of the many agencies listed under 'Sources'.

Some wetlands do not appear wet year round. Best Management Practices - Fish and Wildlife Habitat Management

Harvesting Wood Products

Wooded swamps can, if carefully managed, provide a continuous supply of wood products including fuel wood and cedar posts. Although many tree species normally used for sawlogs do not grow well in wet soils, some hardwood species adapted to wetland areas can furnish timber products.

Many transitional habitats or marginal agricultural lands, including seasonally flooded wetlands, can be reforested. The selection of appropriate tree species will depend on soil and drainage conditions. The continuous presence of surface water, however, usually favours the growth of shrubs and emergent aquatic plants and may be harmful to the survival of tree seedlings.

Additional information on farm forestry is available from the Ontario Ministry of Agriculture, Food and Rural Affairs in the publication, Best Management Practices - Farm Forestry and Habitat Management. There are also many private foresters who can provide site consultation, tree marking services, and information on forestry management in wooded swamps.

Suggestions...

• Changing the amount of tree cover can trigger long-term shifts in the composition of woody species. Seek expert advice before harvesting trees.
• Heavy machinery such as skidders should be avoided during the snow-free season as rutting can result.
• Selectively harvest trees during dry periods or after freeze-up in late autumn or winter to avoid disturbing nesting birds.
• Leave some large diameter trees throughout the forest to provide natural habitat for the territorial requirements of cavity-dwelling species such as squirrels, owls, woodpeckers and wood ducks.
• To attract wildlife, leave some dead trees standing and do not remove older fallen trees. A minimum of 12 small dead trees, greater than 15 centimetres dbh (trunk diameter 1.3 metres above ground), and six large dead trees, greater than 30 centimetres dbh, per hectare is recommended.
• Leave tops and brush from harvested trees to provide cover for wildlife and drumming sites for grouse. Burning brush is not recommended.
• Encourage the growth of conifers, especially cedar or hemlock, which provide habitat for deer and other wildlife.

Aquatic Plant Removal

Aquatic plants are vital to wetland ecosystems and provide food and habitat for many different types of wildlife, as well as spawning and nursery grounds for fish. Aquatic plants stabilize shorelines, prevent erosion and help to improve water quality.

Sometimes it becomes necessary to remove aquatic plants. For example, removal of aquatic plants may be appropriate when nuisance species take hold or when excessive aquatic plant growth occurs because too many nutrients have entered the water. In these circumstances, removal of aquatic plants can actually benefit fish and wildlife and encourage growth of a greater diversity of species by providing both vegetated and open water areas. Any mechanical method may be used to remove aquatic plants providing you do not dredge; however, it is usually only a temporary solution lasting a single season. Avoid the use of herbicides in the water. Use of these chemicals requires an approval from the Ontario Ministry of Environment and Energy. Keep in mind that any plant removal will affect the wetland and its wildlife. Ask yourself if there is some other way of solving the problem, and preventing future problems.

Removal of some aquatic plants may benefit wetlands. Ontario Ministry of Natural Resources

Suggestions...

• Ensure septic systems are functioning properly, reduce the use of fertilizers, carefully time the application of fertilizers, and reduce agricultural runoff. This decreases the amount of nutrients entering the wetland.
• Physical removal, such as hand pulling or raking is one of the most environmentally sound methods to control aquatic plants.
• Be sure to remove all of the aquatic plants from the water otherwise they may root again. Moreover, dead aquatic plants will decompose and remove oxygen from the water.

Constructing Docks and Boathouses

Many wetland areas bordering lakes and streams are used for fishing and boating. Care should be taken to ensure that structures built for these activities do not harm fish and wildlife habitat. Docks and boathouses should be carefully planned, built and located. Solid foundations should be avoided since they impede the movement of fish, destroy aquatic plants, disturb underwater sediments, and destroy wildlife habitat including critical fish spawning areas. A work permit is required from the Ontario Ministry of Natural Resources for the construction of any solid structures in the water.

Carefully built docks avoid harming habitat. Ontario Ministry of Natural Resources

Suggestions...:

• Seek expert guidance on timing of construction and site selection to avoid disturbing wildlife, and to avoid placing structures in spawning or nesting areas.
• If docks and boathouses must be situated at the edge of wetland areas, cantilevered, floating and post-supported structures are preferred. This type of structure may actually improve fish habitat by providing shelter and shade. Be careful when selecting wood products since many wood preservatives and building materials can impair water quality. Use metal, plastic, or untreated wood such as cedar, for any part of a structure that will be in the water.
• Boathouses with a marine railway setup which raises and stores boats out of the water are preferred. Construct boathouses above the high water mark taking care to ensure that excavated materials do not disturb wetland areas.

Dredging

Removing soil, gravel or rocks to improve boat access or to deepen open water areas in wetlands can destroy important fish and wildlife habitat. Additionally, dredging can release contaminants that have settled in wetland sediments, adversely affecting water quality. Dredging is generally not favoured because this technique provides only a temporary solution and can cause environmental damage. However, carefully dredged channels sometimes do provide important deeper water habitat for waterfowl and other wildlife. Permits are required from the Ontario Ministry of Natural Resources for most dredging activities.

Suggestions...

• Consider other alternatives and keep the amount of dredging to a minimum. A boat channel should be no wider than six metres.
• Try not to disturb wetland plants and avoid areas used by fish and wildlife for reproduction, rearing young, or cover from predators.
• Avoid dredging activities on windy days or during fish spawning seasons.
• Since dredging may increase sedimentation downstream, the careful use of a silt screen is recommended to contain sediments suspended during dredging operations.
• Additionally, since dredged soils may release contaminants and fine dredged materials may wash back into the water, removed materials should be suitably contained on land above the high water mark.

Dredging is not a favoured option, but does have some applications. Ontario Ministry of Natural Resources

Filling (Not recommended)

Filling a marsh, swamp, bog, or fen is strongly discouraged because it destroys wetland function and may result in the loss of important fish and wildlife habitat. It can also increase downstream flooding by reducing water storage in the floodplain. Filling a wetland could be a violation under the habitat provisions of the Canada Fisheries Act. For further information and to determine if you require a permit, contact your local Ontario Ministry of Natural Resources office.