Foraging geese, vegetation loss and soil degradation in an Arctic salt marsh
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Authors: R. L. Jefferies, and R. F. Rockwell
Date: 2002
Journal: Applied Vegetation Science
Volume: 5
Number: 1
Pages: 7-16
Summary of Methods: Changes in plant cover due to Lesser snow geese (Chen caerulescens caerulescens) herbivory along the salt marshes of La Pérouse Bay, Manitoba (58° 45’ N, 93° 30’ W) were measured every year from 1986 until 1997 (except 1983). Ground cover was recorded in June or early July as two categories, either bare sediment or vegetation along permanent transects. Vegetation was measured as plant cover greater than five percent. Goose fecal counts were conducted weekly at the same time as biomass measurements in six, 4m x 4m plots from 1979 and 1999.
Article Summary / Main Points: Over the course of the 10 year study the proportion of bare soil increased dramatically and many of the transects reached 100%. Goose fecal counts peaked near the middle of the 20 year period, and then declined, while biomass steadily decreased. In addition to increased numbers of geese grubbing causing vegetative cover loss, several late snow melts during the investigation resulted in abnormally heavy grazing pressure. The vegetation loss suggests that the combination of herbivory and climate caused shifts in the steady state of the region’s 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: fecal density, lesser snow geese, chen caerulescens caerulescens, bare soil, bareground, species assemblage, standing crop, grazing, grubbing
Annotation: Lesser snow geese populations have increased along the intertidal flats in northern Manitoba causing a loss of vegetation cover. Overgrazing by migrating waterfowl can cause a vegetative state to cross a threshold; however, in this study the changes occurred in conjunction with abnormal climatic influences. These processes are applicable to other wetland regions with similar herbivory and climate.
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