Including wildlife habitat in the definition of riparian areas: The beaver (Castor canadensis) as an umbrella species for riparian obligate animals

Riparian wildlife is as important as vegetation in maintaining watercourse ecological integrity, yet present riparian buffer guidelines often fail to maintain sufficient terrestrial habitat for a variety of riparian species in North America. This is of particular concern for the conservation of riparian obligate animals, defined as freshwater-dependent species for which the terrestrial habitat immediately adjacent to watercourses is indispensable to complete their life history. Terrestrial habitat requirements of riparian obligate species are reviewed in this paper using the North American beaver (Castor canadensis) as a focal species. As an ecosystem engineer, the beaver has a profound influence on the shape and function of riparian ecosystems and creates diverse habitat patches. Published data show that 95% of woody plants cut by beavers on land are obtained within 50 m of the water's edge. A review of riparian invertebrates, amphibians, reptiles, mammals, and birds indicates that a 50 m-wide riparian buffer (measured from the high water mark) in its natural state (intact native vegetation) is the minimum area for supporting the majority of riparian obligate species. Exceptions are moose and some amphibian species that also need habitat well beyond 50 m from the water's edge to complete their life history. To conserve these wide-ranging species it is recommended that riparian buffers be continuous and integrated in a connectivity plan including upland reserves. Such a watershed-wide plan will also ensure that riparian buffers can serve as travel and dispersal corridors for both riparian and upland wildlife. © 2011 Published by NRC Research Press.