Moose herbivory, browse quality, and nutrient cycling in an Alaskan treeline community
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Authors: E. M. Molvar, R. T. Bowyer, and V. Van Ballenberghe
Date: 1993
Journal: Oecologia
Volume: 94
Number: 4
Pages: 472-479
Summary of Methods: The effects of moose (Alces alces) herbivory on diamond-leaf willow (Salix planifolia pulchra) forage quality and rate of nitrogen mineralization were examined in the Jenny Creek and Savage River drainages in central Alaska (63° 45’ N, 150° W). Two sites of varied moose density (high, low) were divided into sun and shade areas and further divided into three browse categories (high->50%, moderate-25-49% and low-<25%). The proportion of stems browsed per plant during the previous year of growth was measured. Stem samples were collected and analyzed for chemical composition, in vitro dry matter digestibility (IVDMD) and lignin:nitrogen ratio. Willow characteristics, soil characteristics and indices of soil decomposition rates were also measured.
Article Summary / Main Points: Willow location had a greater effect on growth and soil decomposition rate than the browsing pressure in both full-sun and shaded treatments. Plants on the site with less moose herbivory had higher stem growth in shaded areas because soils were thinner and more N limited. Plants on high use sites exhibited greater stem growth in sunny areas due to increased rate of nutrient cycling. Moose browsing increased subsequent growth of stems and leaves on willows. Moose selected for willows growing in the shade. Moose grazing increased annual growth rates of willows through the addition of manure (fertilizer) to the soil and browsing.
Vegetation Types: Riparian and Wetlands
MLRA Ecoregions: 223 Cook Inlet Mountains 228 Interior Alaska Mountains
Agrovoc Control Words: Riparian zones Herbivory Wildlife
Article Review Type: Refereed
Article Type: Documented Case History
Keywords: alces alces, moose, nutrient cycling, salix, willow
Annotation: This non-replicated, one year study and its associated results are applicable to the riparian willow communities of Alaska. As is true for all grazing research, the results are most directly applicable to areas with similar landscapes, species, level and season of use, and weather conditions. More research is needed to determine if these trends remain consistent beyond this riparian habitat. The year to year variation in weather patterns was not taken into account as this is a one year study.
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