The leaf and shoot demography of grazed and ungrazed plants of Carex subspathacea
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Authors: P. M. Kotanen, and R. L. Jefferies
Date: 1987
Journal: Journal of Ecology
Volume: 75
Number: 4
Pages: 961-975
Summary of Methods: The effects of lessor snow geese herbivory on Carex subspathecea were investigated in the salt marshes along La Perouse Bay, Manitoba, Canada. Three exclosed plots were paired with three plots that were open to geese herbivory during growing season of 1984. The leaves on eighty-one shoots within the half meter squared plots were marked in mid-June. Every two weeks until the beginning of September the leaves on each shoot were viewed and designated as alive, new, dead, or grazed. Six pairs of grazed and ungrazed plots were set up in June 1985 to measure shoot births, deaths, and survivorship every two weeks until September 1985.
Article Summary / Main Points: More leaves were produced per shoot in grazed plots; however, grazed plots also had higher leaf death rates. Leaf production declined during the growing season, while leaf mortality was similar over the same time. In both grazed and ungrazed plots, overall leaf births did not exceed leaf deaths so the number of leaves remained similar throughout the summer. Geese did not preferentially select younger leaves. Cumulative shoot production and shoot deaths were similar between grazed and ungrazed plots, but shoot deaths were higher than shoot births in the grazed plots. Geese grazing increased leaf production but did not affect shoot production in these salt marshes.
Vegetation Types: Riparian and Wetlands
MLRA Ecoregions: Not Applicable
Agrovoc Control Words: Riparian zones Rangelands Wildlife
Article Review Type: Refereed
Article Type: Experimental Research
Keywords: lesser snow geese, anser caerulescens caerulescens, sedge-meadow community, plant production, net annual primary production, compensatory growth, exclosures
Annotation: The results of this study are probably site specific due to the unique nature of these salt marshes. More than one summer of data collection and a larger sample size might result in different findings. Both types of plots were previously grazed and by excluding grazing for only one growing season it is difficult to determine the effects of non-grazing over time.
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