Effects of grazing on a salt marsh

  • Published source details Reimold R.J., Linthurst R.A. & Wolf P.L. (1975) Effects of grazing on a salt marsh. Biological Conservation, 8, 105-125.


This study is summarised as evidence for the following.

Action Category

Exclude or remove livestock from historically grazed brackish/salt marshes

Action Link
Marsh and Swamp Conservation
  1. Exclude or remove livestock from historically grazed brackish/salt marshes

    A replicated, controlled, site comparison study in 1972–1974 in two brackish/salt marshes in Georgia, USA (Reimold et al. 1975) reported that plots fenced to exclude livestock had similar patterns of species dominance to grazed areas, but typically contained more vegetation biomass. Statistical significance was not assessed. Over the two years following intervention, smooth cordgrass Spartina alterniflora was dominant in all ten sampled months in both exclosures (48–73% of biomass) and grazed areas (53–66% of biomass). Saltgrass Distichlis spicata and pickleweed Salicornia virginica were subdominants. In 24 of 28 comparisons, the total above-ground biomass of these three species was greater in exclosures (28–362 g/m2) than grazed areas (15–277 g/m2). For the grasses, data were also reported for live and dead biomass separately, and showed similar patterns (see original paper). A nearby natural marsh was dominated by smooth cordgrass in 7 of 10 sampled months (51–69% of biomass) but pickleweed in the other three (54–65% of biomass). In every month with a fair comparison to the natural marsh, exclosures contained less biomass of both smooth cordgrass (exclosures: 82–345 g/m2; natural: 184–439 g/m2) and pickleweed (exclosures: 38–99 g/m2; natural: 194–490 g/m2). Methods: In May 1972, electric fences were installed to exclude livestock from five 200-m2 areas of a coastal brackish/salt marsh (salinity 5–35 ppt). The rest of this marsh remained “heavily” grazed. The study does not report details of the livestock or grazing intensity. Above-ground vegetation was sampled (cut, dried and weighed) approximately monthly over the following two years: from the exclosures, the grazed area and a nearby natural (never-grazed) marsh.

    (Summarised by: Nigel Taylor)

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