Restoring habitats for migrating species

Restoration for Migrating Species

Habitat destruction is one of the primary causes of endangerment to migrating species. Birds, waterfowl, fish and marine mammals may be threatened when the environments that they depend upon for survival during migration are degraded or destroyed.

Some species have adapted well to environmental changes. The peregrine falcon, for example, has adapted to become a top predator in cities by nesting on high-rise buildings. On the other hand, many species require particular habitats for survival during migration. Restoration of these habitats is the only way to ensure that these species will continue to exist. Let’s have a look at some of the major types of habitat degradation, the species that are affected and what is being done to correct the problem.

Wetlands

Wetlands are permanently or seasonally saturated areas that host a variety of species, both plant and animal. In addition, many wetlands act as rest stops for migrating waterfowl and birds. Local species lose their habitats when the wetlands are destroyed, but so do migrating species that pass through the area.

Wetland restoration may be a complex process with many aspects and consequences. Providing access for migrating species is only one part of the restoration process. In some cases, a wetland may be restored by simply removing drainage and allowing the area to once again become saturated. However, many former wetlands are now in the heart of urban areas. In these cases, alternative areas must be constructed near the location of the original wetland so that migrating species may once again use the area.

Urban Green Spaces

Heavy urbanization can destroy many habitats that are used by migrating species. Like wetlands, forests and grasslands are common way stations for migratory birds. Cities like Portland, Oregon have included green spaces in their planning and zoning for many years. Aside from providing outdoor recreation for citizens and visitors, these green spaces provide access for migratory birds and wildlife that would otherwise be shut out in an urban environment.

Dams and Migratory Fish

Of course, birds are not the only migratory animals that have suffered from a loss of habitat. Anadromous fish are fish that live most of their lives in the sea, but enter freshwater rivers to spawn. Pacific Salmon, Steelhead Trout, Atlantic Salmon and American Shad are examples of anadromous fish. Dam and reservoir projects which were originally built to provide flood control and hydroelectric power have limited the access of anadromous fish to their historical spawning waters.

In order to provide access to spawning waters, some dams in the Pacific Northwest are now being demolished. The demolition of the Condit Dam, for example, is expected to open miles of spawning waters to Pacific Salmon that are near extinction.

In many cases it is neither practical nor desirable to tear down a dam. However, fish ladders may be installed to allow the spawning fish back upstream as well allowing the fingerlings to bypass the dam on their way to the sea.