Large ruminant herbivores like moose spend most of their time foraging and ruminating
to acquire and process enough plant biomass to meet energy and nutrient requirements. In
northeastern Minnesota, moose forage in a mosaic of forest stands with ages shaped by harvest
and other disturbances. Distribution and abundance of browse species varies across the landscape
and each browse species has unique growth patterns and a patchy distribution within and among
different stand types. We measured browse availability and use along foraging paths of GPS
radio-collared moose and within randomly selected regenerating stands in northeastern
Minnesota. We measured all sites using traditional methods and a method that simulates moose
foraging behavior by measuring large feeding stations. At each site we measured available
species composition and available browse density. We tested three hypotheses: (1) the proportion
of available browse species common in the diet along foraging paths would be greater than within
randomly selected regenerating stands, (2) the density of available browse species would be
greater along foraging paths than within randomly selected regenerating stands, and (3) the
density of available twigs would be highest in young stands and decrease with stand age. Paper
birch, willow, and quaking aspen were common in young stands while hazel, mountain maple,
and balsam fir (winter) or juneberry (summer) were common in older stands. Browse density also
changed with stand age, but the changes in species composition and browse density were similar
along foraging paths and within randomly selected regenerating stands indicating that moose
habitat restoration projects can effectively create forage for moose. In areas with and without
collared moose the simulated browsing method was an effective tool for measuring browse
availability and use.
University of Minnesota Duluth. College of Education and Human Service Pro, Natural Resources Research Institute
Ward, Rachel L; Moen, Ronald.
Effects of Stand Age on Species Composition and Browse Density in Northeastern Minnesota.
University of Minnesota Duluth.
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