Manuscript Report 150

150. Larter N.C., J.A. 2003. Wet Sedge Meadow Habitat of Southern Banks Island Excluded From Grazing By Large Herbivores For Five Years: Effects On Above Ground Standing Crop. 26 pp

ABSTRACT

Grazing exclosures were erected in wet sedge meadow habitat on southern Banks Island at the start of the 1993 growing season.  Exclosures (n=5) were established in areas of high (1.6-1.9 muskox/km²) and low (0.3-0.4 muskox/km²) muskox density.  In late-August (21-25), we clipped the aboveground standing crop of forages in plots (n=2) located within and adjacent to each exclosure.  Late-August clipping within and adjacent to exclosures was repeated annually in 1994, 1996, and 1997.  Early snow and freezing temperatures prevented clipping in late-August 1995.  Exclosures in the low density muskox area were often damaged, and the experiment was ended in this area after one season; time series data were limited to the area of high muskox density.  Mean aboveground standing crop (dry weight) of sedge material varied annually (P<0.05) in both grazed and excluded areas, ca. 500-1100 kg/ha, being greatest in 1997 and lowest in 1993 and 1994.  The mean proportion of live sedge material (dry weight) in aboveground sedge biomass also varied annually (P<0.05) in both grazed and excluded areas, ca. 0.05-0.40, being lowest in 1996.  The aboveground standing crop of sedge exposed to grazing did not differ (P>0.9) from that found in areas excluded from grazing, regardless of the amount of time excluded from grazing.  However, the proportion of live sedge in the late-August aboveground sedge standing crop in excluded areas increased (P<0.02) relative to grazed areas over time implying selective herbivory of green sedge material.  At current grazing levels the data are not indicative of degradation of wet sedge meadow habitat during summer.