Historic and Recent Landscape Changes in Relation to Beaver Activity in Voyageurs National Park, Minnesota, USA

Name: Historic and Recent Landscape Changes in Relation to Beaver Activity in Voyageurs National Park, Minnesota, USA
Published: 2010

Host, George; Meysembourg, Paul

Bried Description: A Microsoft Access Database containing data related to the historic and recent landscape changes in relation to beaver activity in Voyageurs National Park. Full Description: Beaver (Castor canadensis) have the ability to significantly alter landscape structure through the creation of impoundments, here defined as wetland or open water systems created as beaver dams obstruct the flow on low-gradient streams (Collen & Gibson 2001,Wright et al. 2002). These landscape changes have wide-ranging effects, from influences on fish populations (Snodgrass & Meffe 1998,Schlosser & Kallemeyn 2000) to watershed biogeochemistry (Naiman et al. 1994). The proportion of the landscape in impoundments fluctuates with beaver populations, and declines in populations result in the natural succession of impoundments from open-water systems to other wetland types. The dynamics of beaver pond creation and abandonment were the subject of a series of seminal landscape ecology studies in the late 1980s and early 1990s (Naiman et al. 1988,Johnston & Naiman 1990a,Johnston & Naiman 1990b,Pastor et al. 1993). These works were based largely on the interpretation of aerial photography to delineate the various wetland types associated with beaver activities (Johnston & Naiman 1990b). Historic patterns of beaver impoundments within the Kabetogama Peninsula were delineated from six aerial photo sets spanning 46 years: 1940, 1948, 1961, 1972, and 1986 (Johnston & Naiman 1990a,Johnston & Naiman 1990b). Geographic information system technologies, newly adopted by ecologists (Johnson & Host 2010), were used to answer ecological questions related to the ecosystem engineering abilities of beavers, such as the rate of impoundment creation and expansion in relation to beaver population dynamics and the distribution of seral stages of beaver-related impoundments (hereafter impoundments) across the landscape. In a parallel study, Broschart and colleagues used MN DNR transect surveys to develop a model predicting beaver colony abundance from the proportions of wetland types on the Kabetogama Peninsula (Broschart et al. 1989). These studies illuminated the extensive impact beavers can have on boreal landscapes, demonstrating that beavers were responsible for significant land cover changes over 15% of the Kabetogama landscape in a 50-year span.