Long-term changes of salt marsh communities by cattle grazing
-
Published source details
Andresen H., Bakker J.P., Brongers M., Heydemann B. & Irmler U. (1990) Long-term changes of salt marsh communities by cattle grazing. Vegetatio (now Plant Ecology), 137-148.
Published source details Andresen H., Bakker J.P., Brongers M., Heydemann B. & Irmler U. (1990) Long-term changes of salt marsh communities by cattle grazing. Vegetatio (now Plant Ecology), 137-148.
Actions
This study is summarised as evidence for the following.
| Action | Category | |
|---|---|---|
|
Reduce intensity of livestock grazing: brackish/salt marshes Action Link |
 |
|
|
Exclude or remove livestock from historically grazed brackish/salt marshes Action Link |
|
-
Reduce intensity of livestock grazing: brackish/salt marshes
A controlled study in 1980–1988 of a salt marsh in northern Germany (Andresen et al. 1990) reported that less intensely grazed plots had a taller vegetation canopy than more intensely grazed plots, but that reducing grazing intensity had little effect on understory height or vegetation cover. Statistical significance was not assessed. After eight years, the vegetation canopy was 26–89 cm tall in plots grazed at low or medium intensity (vs 0–55 cm tall in a plot grazed at high intensity). In contrast, understory grasses reached a similar height under all grazing intensities (low: 6–22 cm; medium: 5–10 cm; high: 3–14 cm). The distribution of different vegetation types was broadly similar across all grazing intensities, with similar communities at similar elevations. However, the plots grazed at low/medium intensity supported a slightly larger total vegetated area than the plot grazed at high intensity (data reported as maps), and a slightly greater frequency of the dominant saltmarsh grass Puccinellia maritima (data reported as frequency classes). Methods: Three plots were established in a coastal salt marsh, historically grazed by 2.0 cattle/ha. From 1980, grazing intensity was reduced in two of the three plots: one to low intensity (0.5 cattle/ha) and one to medium intensity (1.0 cattle/ha). The third plot remained grazed by 2.0 cattle/ha. In 1988, vegetation was surveyed along one 750-m transect/plot, at 50 m intervals. Cover was assessed using a point quadrat (50 points/interval). Vegetation stands were mapped.
(Summarised by: Nigel Taylor)
-
Exclude or remove livestock from historically grazed brackish/salt marshes
A controlled study in 1980–1988 on a salt marsh in northern Germany (Andresen 1990) reported that a plot fenced to exclude livestock had greater overall vegetation coverage, different cover of some individual plant species, and taller vegetation than a plot that remained intensely grazed. Statistical significance was not assessed. After eight years, the total vegetated area was greater in the exclusion plot than the grazed plot, especially closer to the sea (data reported as maps). In the exclusion plot, vegetation stands further from the sea became dominated by couch grass Elymus pycnanthus at the expense of saltmarsh grass Puccinellia maritima, perennial ryegrass Lolium perenne and red fescue Festuca rubra (data reported as frequency classes). The exclusion plot also contained taller vegetation (understory grasses: 7–32 cm; canopy: 41–87 cm) than the grazed plot (understory grasses: 3–14 cm; canopy: 0–55 cm). Methods: In 1980, a 10-ha plot in a coastal salt marsh was fenced to exclude cattle. Another plot in the marsh remained heavily grazed (2 cattle/ha). Vegetation stands were mapped in 1988. Vegetation was surveyed in more detail along one 750-m transect/plot, at 50 m intervals. Cover was assessed using a point quadrat (50 points/interval).
(Summarised by: Nigel Taylor)
)_2023.JPG)
