Oak Hammock Marsh
Encyclopedia
Oak Hammock Marsh consists of approximately 20 square kilometres of open marsh, and a slightly smaller area of surrounding woods and grasslands. The total Wildlife Management Area is 36 square kilometres. It is located approximately 20 km north and slightly west of the northern suburbs of Winnipeg
, Manitoba
, Canada
, near the town of Stonewall, Manitoba
.
Oak Hammock Marsh is listed as a Wetland of International Importance under the Ramsar Convention
, and is also a globally significant Important Bird Area
.
and fen
near the south-western corner of Lake Winnipeg
. This larger marsh had the original English name of St. Andrews Bog. But the original wetland underwent drainage for agricultural purposes beginning in 1897, and by the early 1960s all but 60ha had been drained. Measures to restore a portion of the wetland began in 1967 when the Governments of Manitoba
and Canada
embarked on a cooperative program with Ducks Unlimited
Canada and other wildlife conservation organizations to restore marginal agricultural lands to a state suitable for wildlife.
By 1974, 3450ha of land had been purchased and 22 km of dykes built to trap and hold water in three dyke-separated marsh compartments. In addition, 58 nesting islands were constructed within the three compartments. In 1984, the Manitoba
government signed a further development agreement with Ducks Unlimited
Canada to construct water control structures, water supply works, more nesting islands, additional dykes, and create a fourth compartment.
and cattail
, and therefore maintains the vegetation cover of the marsh; otherwise, the natural tendency would be for the marsh to become over several years simply a shallow lake, with a sharply defined shoreline and little nesting cover. Furthermore, not all of the adjacent purchased land has been allowed to grow wild. Cereal grain crops are planted in some of it, in order to supply migrating waterfowl with an autumn food supply while reducing crop losses on local farms.
wetland
s, supports many wildlife species besides game birds, .
The marsh itself is closed to hunting, but game birds (primarily mallards, snow geese, and Canada geese) are hunted in the autumn when they leave the marsh to feed in the surrounding grain fields. The waterfowl is additionally protected by a buffer zone extending 1km from the water inside which hunting is prohibited, this protection extending outside of the WMA in some locations.
national head office in Canada, in a building that also serves as a public Interpretive Centre for the marsh. Boardwalks from the Interpretive Centre allow public access to the marsh and dykes. The building of a head office and public facility so close to critical wildlife habitat was the cause of controversy in the 1980s. Opponents believed the traffic associated with the building would disturb the wildlife. These concerns have proven unfounded, as the wildlife have since grown quite accustomed to the building and its people (the building's roof is now a popular nesting site).
Winnipeg
Winnipeg is the capital and largest city of Manitoba, Canada, and is the primary municipality of the Winnipeg Capital Region, with more than half of Manitoba's population. It is located near the longitudinal centre of North America, at the confluence of the Red and Assiniboine Rivers .The name...
, Manitoba
Manitoba
Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, near the town of Stonewall, Manitoba
Stonewall, Manitoba
Stonewall is a town in the Canadian province of Manitoba with a population of 4,376 as of the 2006 census. The town is situated approximately north of Winnipeg on PTH 67. It is known for its limestone quarries. The local festival is the Quarry Days which is usually held over three days in August...
.
Oak Hammock Marsh is listed as a Wetland of International Importance under the Ramsar Convention
Ramsar Convention
The Ramsar Convention is an international treaty for the conservation and sustainable utilization of wetlands, i.e., to stem the progressive encroachment on and loss of wetlands now and in the future, recognizing the fundamental ecological functions of wetlands and their economic, cultural,...
, and is also a globally significant Important Bird Area
Important Bird Area
An Important Bird Area is an area recognized as being globally important habitat for the conservation of bird populations. Currently there are about 10,000 IBAs worldwide. The program was developed and sites are identified by BirdLife International...
.
History
The marsh is a remnant of an originally 470 square kilometre area of marshMarsh
In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....
and fen
Fen
A fen is a type of wetland fed by mineral-rich surface water or groundwater. Fens are characterised by their water chemistry, which is neutral or alkaline, with relatively high dissolved mineral levels but few other plant nutrients...
near the south-western corner of Lake Winnipeg
Lake Winnipeg
Lake Winnipeg is a large, lake in central North America, in the province of Manitoba, Canada, with its southern tip about north of the city of Winnipeg...
. This larger marsh had the original English name of St. Andrews Bog. But the original wetland underwent drainage for agricultural purposes beginning in 1897, and by the early 1960s all but 60ha had been drained. Measures to restore a portion of the wetland began in 1967 when the Governments of Manitoba
Manitoba
Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...
and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
embarked on a cooperative program with Ducks Unlimited
Ducks Unlimited
Ducks Unlimited is an international non-profit organization dedicated to the conservation of wetlands and associated upland habitats for waterfowl, other wildlife, and people. It currently has approximately 780,000 members, mostly in the United States and Canada.-Introduction:Ducks Unlimited was...
Canada and other wildlife conservation organizations to restore marginal agricultural lands to a state suitable for wildlife.
By 1974, 3450ha of land had been purchased and 22 km of dykes built to trap and hold water in three dyke-separated marsh compartments. In addition, 58 nesting islands were constructed within the three compartments. In 1984, the Manitoba
Manitoba
Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...
government signed a further development agreement with Ducks Unlimited
Ducks Unlimited
Ducks Unlimited is an international non-profit organization dedicated to the conservation of wetlands and associated upland habitats for waterfowl, other wildlife, and people. It currently has approximately 780,000 members, mostly in the United States and Canada.-Introduction:Ducks Unlimited was...
Canada to construct water control structures, water supply works, more nesting islands, additional dykes, and create a fourth compartment.
Management
The marsh is a re-constructed and managed wetland, designed for the creation of a waterfowl breeding and migratory habitat. Water levels in the marsh are carefully controlled. It is common during wet years (when waterfowl have an abundance of alternative nesting sites) for the water level in one or more of the compartments to be lowered for the summer, creating an extensive area of dried mudflats. This drying and later reflooding promotes the growth of emergent marsh plants such as bulrushScirpus
The plant genus Scirpus consists of a large number of aquatic, grass-like species in the family Cyperaceae , many with the common names club-rush or bulrush . Other common names are deergrass or grassweed.The genus has a cosmopolitan distribution, and grows in wetlands and moist soil...
and cattail
Typha
Typha is a genus of about eleven species of monocotyledonous flowering plants in the family Typhaceae. The genus has a largely Northern Hemisphere distribution, but is essentially cosmopolitan, being found in a variety of wetland habitats...
, and therefore maintains the vegetation cover of the marsh; otherwise, the natural tendency would be for the marsh to become over several years simply a shallow lake, with a sharply defined shoreline and little nesting cover. Furthermore, not all of the adjacent purchased land has been allowed to grow wild. Cereal grain crops are planted in some of it, in order to supply migrating waterfowl with an autumn food supply while reducing crop losses on local farms.
Hunting
Critics contend that the marsh simply a "duck factory" for the benefit of hunters. Supporters believe that it would be unrealistic to expect that the required funds to recreate the marsh would have been forthcoming if wild ducks had no economic and recreational value to sportsmen. Oak Hammock Marsh, like other prairiePrairie
Prairies are considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type...
wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
s, supports many wildlife species besides game birds, .
The marsh itself is closed to hunting, but game birds (primarily mallards, snow geese, and Canada geese) are hunted in the autumn when they leave the marsh to feed in the surrounding grain fields. The waterfowl is additionally protected by a buffer zone extending 1km from the water inside which hunting is prohibited, this protection extending outside of the WMA in some locations.
Ducks Unlimited National Office
The western shore of the marsh is home to Ducks UnlimitedDucks Unlimited
Ducks Unlimited is an international non-profit organization dedicated to the conservation of wetlands and associated upland habitats for waterfowl, other wildlife, and people. It currently has approximately 780,000 members, mostly in the United States and Canada.-Introduction:Ducks Unlimited was...
national head office in Canada, in a building that also serves as a public Interpretive Centre for the marsh. Boardwalks from the Interpretive Centre allow public access to the marsh and dykes. The building of a head office and public facility so close to critical wildlife habitat was the cause of controversy in the 1980s. Opponents believed the traffic associated with the building would disturb the wildlife. These concerns have proven unfounded, as the wildlife have since grown quite accustomed to the building and its people (the building's roof is now a popular nesting site).