Study

Effects of grazing and inundation on pasture quality and seed production in a salt marsh

  • Published source details Pehrsson O. (1988) Effects of grazing and inundation on pasture quality and seed production in a salt marsh. Vegetatio (now Plant Ecology), 113-124.

Actions

This study is summarised as evidence for the following.

Action Category

Exclude wild vertebrates: brackish/salt marshes

Action Link
Marsh and Swamp Conservation

Exclude or remove livestock from historically grazed brackish/salt marshes

Action Link
Marsh and Swamp Conservation
  1. Exclude wild vertebrates: brackish/salt marshes

    A replicated, controlled, before-and-after study in 1980–1983 on a coastal salt marsh in Sweden (Pehrsson 1988) found that excluding geese increased the height of saltmarsh grass Puccinellia maritima. In 1981 and 1982, saltmarsh grass was taller in plots from which geese had been excluded (16–24 cm) than plots left open to geese (13–16 cm). In 1980, before intervention, the opposite was true: saltmarsh grass was shorter in plots destined for goose exclusion (10 cm) than plots destined to remain open to geese (11 cm). The study also noted broadly similar changes in vegetation cover under both treatments, between 1980 and 1983. Cover of saltmarsh grass consistently declined, whilst cover of creeping bentgrass Agrostis stolonifera and saltmarsh bulrush Scirpus maritimus consistently increased (statistical significance not assessed; data not clearly reported). Methods: In late 1979, four 25-m2 plots were established in grassy areas of a salt marsh and fenced to exclude cattle. In 1981, geese were also excluded from two of the plots using circular chicken nets. Vegetation was surveyed using point quadrats each autumn before goose exclusion (1980) and after goose exclusion (1981–1983). Height was measured for 3–186 plants/species/treatment/year.

    (Summarised by: Nigel Taylor)

  2. Exclude or remove livestock from historically grazed brackish/salt marshes

    A replicated, paired, controlled study in 1979–1983 on a coastal salt marsh in Sweden (Pehrsson 1988) found that plots from which cattle were excluded contained taller grasses than plots open to grazing. This was true in three of three years for creeping bentgrass Agrostis stolonifera (exclusion: 15–20 cm; grazed: 6–7 cm) and saltmarsh grass Puccinellia maritima (exclusion: 10–21 cm; grazed: 5–6 cm). The study also noted broadly similar changes in cover of these species under both treatments over four years, but that cover was more often higher in exclusion than grazed plots (statistical significance not assessed; data not clearly reported). Methods: In autumn 1979, five pairs of 25-m2 plots were established on a grazed salt marsh (0.1–0.9 cattle/ha). One plot in each pair was fenced to exclude cattle. Geese were also excluded from two of these plots from 1981. Vegetation was surveyed using point quadrats each autumn between 1979 and 1983 (including height measurements for 12–348 plants/species/treatment/year, between 1980 and 1982).

    (Summarised by: Nigel Taylor)

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