Changes in the composition and standing crop of salt-marsh communities in response to the removal of a grazer
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Authors: D. R. Bazely, and R. L. Jefferies
Date: 1986
Journal: Journal of Ecology
Volume: 74
Number: 3
Pages: 693-706
Summary of Methods: The effects of excluding grazing by lesser snow geese (Anser caerulescens caerulescens) on the salt marsh at La Perouse Bay, Manitoba on species composition, live standing crop and plant litter have been measured in a salt marsh. Each year from 1979 to 1984 a 5 x 5 m exclosure was established and maintained throughout the duration of the study. Vegetative measurements were taken in early August of 1982, 1983, and 1984 within each exclosure and on adjacent grazed sites.
Article Summary / Main Points: The number of higher plants was 6 species on grazed sites compared to 16 within the exclosure that had been established for five years. Differences in species composition and frequency were detected between grazed and ungrazed sites after four years of no grazing. Dicotyledons, such as Potentilla egedii and Plantago maritima, increased in frequency in the absence of grazing, and Carex subspathacea replaced Puccinellia phryganodes as the dominant graminoid. The cessation of grazing changed not only in the species composition but also increased primary production within one to two years. Once grazing pressure is relaxed, it is unlikely that the grazers will utilize the modified plant community as forage. The change represents a loss of preferred forage.
Vegetation Types: Riparian and Wetlands
MLRA Ecoregions: Not Applicable
Agrovoc Control Words: Riparian zones Rangelands Geese
Article Review Type: Refereed
Article Type: Experimental Research
Keywords: lesser snow geese, anser caerulescens caerulescens, species composition, salt marsh, potentilla egedii, plantago maritima, carex subspathacea, puccinellia phryganodes, grazing, exclosures
Annotation: This study has limited applicability to the range managers in the western United States. This study only had one exclosure established each year, limiting the area of influence of these findings.
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