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Beaver Life History & Biology. Dr. John Stella Anna Harrison SUNY ESF 19 th September 2011. The Colony. Family/colony unit (6-8 related individuals) Active colonies spaced at least 0.25 miles from other colonies Mark territory with scent mounds. L ove of the water.
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Beaver Life History & Biology Dr. John Stella Anna Harrison SUNY ESF 19th September 2011
The Colony • Family/colony unit (6-8 related individuals) • Active colonies spaced at least 0.25 miles from other colonies • Mark territory with scent mounds
Love of the water Lodge is the central place for a beaver colony Beaver more agile in water than on land Aquatic habitat protects them from predators Attempt to maximize time in water, minimize time on land
Food preferences Spring/Summer diet: herbaceous, aquatic vegetation Fall/Winter diet: trees and tubers Beaver collect food for winter in food cache, store next to lodge
Initial site establishment • Well established drivers (Bradt 1938) that create largest possible pond area: • Low stream gradient • Small stream cross-sectional area
Beaver site establishment • Dams also built as ‘safe’ transportation corridors to connect large ponds
Beaver site establishment • Ultimate purpose of dam: location for lodge
Beaver Impacts: landscape change • Beaver change landscape from terrestrial to aquatic • Most landscape change occurs in first 20 years of occupancy
Beaver impacts: increase wetland area • Greater landscape diversity • Wright 2002 • Waterfowl habitat • Amphibian habitat • Karraker and Gibbs 2009 9
New Pond Pond Meadow Old Pond Beaver impacts: Possible beaver pond succession post abandonment Stream Naiman 1988
Beaver impacts: forest structure • Trees used for food anddam/lodge building resources • Beaver can ‘clear cut’ areas with young trees 11
Beaver impacts: forest structure • Remove understory and canopy trees • Open areas up to shrubby species
Generalized Central place foraging model P Most Preferred Opportunistic Selectivity Non-preferred Distance from the impoundment Beaver Impacts: foraging
Ecosystem Engineer slides I’m not sure if/where you’ll want to use these, but they are a good example of culvert blockage, flooding, dam removal and beaver deceiver at HWF
Ecosystem engineer Photo: Adirondack Ecological Center
Ecosystem engineer 16 Photo: Adirondack Ecological Center