Predicting Beaver Colony Density in Boreal Landscapes

Geomorphological implications of engineering bed sediments by lotic animals

“…This local action of trees and beavers varied over the recent centuries, during which humans removed trees and heavily hunted beavers until protection and restoration resulted in recovery from these human actions (e.g., Montgomery, 1997;Butler and Malanson, 2005). Beyond this complication by variation over time, many interrelated variables affect the geomorphic action of riparian trees (e.g., sediment supply and size, nature of bank material, type and age of riparian vegetation, particularly of the root system; Hähne, 1982;Pflug, 1982;Montgomery, 1997) and beavers (e.g., water depth, nature of bank material, tree canopy cover; Broschart et al, 1989;Gurnell, 1998). Further complications relate to interactions between the riparian vegetation and beavers.…”

Beaver population fluctuations and tropospheric methane emissions in boreal wetlands

“…Third, the abundance of beaver on the Kabetogama Peninsula is representative of boreal North America. This is probably an overestimate but could be corrected easily with better population data from other areas (Broschart et al 1989). Finally, temperature and insolation differences within the boreal region are minor.…”

“…Woodwell et al (1978) estimate the global area of boreal forest to be 12 x 106km2; about 40% of this is in North America yielding as estimate of 4.8 x lo6 km2 of boreal forest with potential for beaver impoundment. Following these calculations and the assumptions listed above, an estimate of 2.18 x 10" grams carbon (as methane) released each year for beaver created wetlands in the North American boreal forest is probably a maximum, given that beaver are probably not generally as dense elsewhere as they are on the Kabetogama Peninsula (Broschart et al 1989). The open-water area of beaver ponds on the Kabetogama Peninsula increased 86-fold (from 0.16km2 to 13.7 km2) between 1940 and 1986 Johnston & Naiman 1990a, b).…”

Habitat selection of an expanding beaver (Castor fiber) population in central and upper Morava River basin

“…Studies carried out on both beaver species European beaver C. fiber and North American beaver Castor canadensis mostly contain only data obtained during one season (Slough and Sadleir 1977;Beier and Barrett 1987;Dieter and McCabe 1989;McComb et al 1990;Robel et al 1993;Hartman 1996; Barnes and Mallik 1997;Suzuki and McComb 1998;Fustec et al 2001;Fustec et al 2003). Howard and Larson (1985), Broschart et al (1989), and Fryxell (2001) have all described habitat selection based on a longer period, however, but the research was conducted in study areas which were already occupied by beavers when the research began. Hartman (1996) highlights that beaver habitat studies carried out in populations which are near carrying capacity may give little information about quality or preference of habitat but rather give more appropriate information on usable and unusable habitat.…”