Hudson Plains salt marshes

The salt marshes of the Hudson Plains are an exception to the general finding that coastal habitats in less-developed areas are healthy. These coastal marshes are under stress from the increasing population of mid-continent lesser snow geese. The goose population increase is mainly due to human influences outside of the region, including increased supply of agricultural food on wintering grounds in the United States and along migration routes, along with declining harvest and the development of refuges.33, 34

Loss of salt marsh vegetation from snow goose foraging, Hudson Plains

Areas with vegetation loss, La Perouse Bay, Manitoba
Map: loss of salt marsh vegetation in La Perouse Bay. Click for graphic description (new window).
Source: adapted from Jefferies et al., 200632

Intensive foraging by snow geese has led to vegetation loss, shifts in plant community composition, and exposure and sometimes erosion of sediment.32, 34, 35 This results in large areas of exposed sediment that are resistant to re-colonization because few plants can germinate or establish themselves in the saline sediments. Approximately one third of the coastal salt marsh vegetation in the Hudson Plains Ecozone+ has been destroyed by geese and a far greater area will be severely damaged if this intense foraging pressure continues.36

Mid-continent lesser snow goose population
Millions, 1970 to 2008
Graph: mid-continent lesser snow goose population. Click for graphic description (new window). Photo: Snow goose ©
Source: adapted from Canadian Wildlife Service Waterfowl Committee, 200937