Study

Effects of grazing management on biodiversity across trophic levels – the importance of livestock species and stocking density in salt marshes

  • Published source details van Klink R., Nolte S., Mandema F.S., Lagendijk D.D.G., Wallis De Vries M.F., Bakker J.P., Esselink P. & Smit C. (2016) Effects of grazing management on biodiversity across trophic levels – the importance of livestock species and stocking density in salt marshes. Agriculture, Ecosystems & Environment, 235, 329-339.

Actions

This study is summarised as evidence for the following.

Action Category

Change type of livestock

Action Link
Terrestrial Mammal Conservation

Change type of livestock grazing: brackish/salt marshes

Action Link
Marsh and Swamp Conservation

Reduce intensity of livestock grazing: brackish/salt marshes

Action Link
Marsh and Swamp Conservation

Reduce intensity of grazing by domestic livestock

Action Link
Terrestrial Mammal Conservation
  1. Change type of livestock

    A replicated, randomized, paired sites, controlled study in 2010–2013 on a coastal salt marsh in the Netherlands (van Klink et al. 2016) found that plots grazed by cattle contained more signs of vole Microtus spp. presence than did plots grazed by horses. After four years, a greater proportion of surveyed quadrats contained signs of vole presence in plots grazed by cattle than in plots grazed by horses (data not reported). Twelve plots were established (in three sets of four plots) on a grazed salt marsh. From 2010, six plots (two random plots/set) were grazed by each livestock type: cows (600 kg) or horses (700 kg). Grazing occurred in summer (June–October) only. Half of the plots were grazed at high intensity (1.0 animal/ha) and half were grazed at low intensity (0.5 animals/ha). In October 2013, sixty quadrats (2 m2) were surveyed in the higher elevations of each plot for signs of vole presence (runways, fresh plant fragments or faecal pellets). Some flooded quadrats were excluded from analyses.

    (Summarised by: Nigel Taylor)

  2. Change type of livestock grazing: brackish/salt marshes

    A replicated, randomized, paired, controlled, before-and-after study in 2009–2013 on a salt marsh in the Netherlands (van Klink et al. 2016) found that grazing by cattle and horses had similar effects on plant species richness, vegetation height and the area of vegetation dominated by sea couch grass Elytrigia atheria. Over four years, plots grazed by cattle and horses did not significantly differ in plant species richness (both 8–14 species/16 m2) or average vegetation height (cattle: 9–22 cm; horses: 10–17 cm). This was true in both near to and far from the sea. Over four years, and across the whole marsh, plots grazed by cattle and horses experienced a statistically similar change in area of couch-grass-dominated vegetation (data not reported). Methods: In 2009, twelve 11-ha plots were established (in three sets of four) on a historically grazed coastal salt marsh. From 2010, six plots (two random plots/set) were grazed in summer by each livestock type: cows or horses. Half of the plots were grazed at high intensity (1.0 animal/ha) and half were grazed at low intensity (0.5 animals/ha). Vegetation height and plant species were recorded in late August/early September 2010–2013, in eight 16-m2 quadrats/plot/year. The area of couch-grass-dominated vegetation was mapped using aerial photographs taken before (2009) and four years after (2013) grazing treatments were applied. Some of the plots in this study were also used in (1) and (3).

    (Summarised by: Nigel Taylor)

  3. Reduce intensity of livestock grazing: brackish/salt marshes

    A replicated, randomized, paired, controlled, before-and-after study in 2009–2013 on a salt marsh in the Netherlands (van Klink et al. 2016) found that lower grazing intensities increased vegetation height in two of two comparisons but never increased plant species richness, and had no significant effect on the area of vegetation dominated by sea couch grass Elytrigia atheria. Both far from and near to the sea, vegetation was taller in plots grazed at low intensity (14–22 cm average height) than in plots grazed at high intensity (9–12 cm average height). Far from the sea, plant species richness was lower in plots grazed at low intensity (12–13 species/16 m2) than in plots grazed at high intensity (14 species/16 m2). However, near to the sea, plant species richness did not significantly differ between grazing intensities (low: 8 species/16 m2; high: 9 species/16 m2). Finally, over four years of grazing and across the whole marsh, the area of couch-grass-dominated vegetation experienced a statistically similar change under both grazing intensities (although with a trend towards a greater reduction under a higher grazing intensity; data not reported). Methods: In 2009, twelve plots were established (in three sets of four) on a historically grazed coastal salt marsh. From 2010, six plots (two random plots/set) were grazed at each intensity: low (0.5 animals/ha) or high (1.0 animal/ha). Grazing occurred in summer (June–October) only. Half of the plots were grazed by cows and half by horses. Vegetation height and plant species were recorded in late August/early September 2010–2013, in eight 16-m2 quadrats/plot/year. The area of couch-grass-dominated vegetation was mapped using aerial photographs taken before (2009) and four years after (2013) grazing treatments were applied. Some of the plots in this study were also used in (6) and (9).

    (Summarised by: Nigel Taylor)

  4. Reduce intensity of grazing by domestic livestock

    A replicated, randomized, paired sites, controlled study in 2010–2013 on a coastal salt marsh in the Netherlands (van Klink et al. 2016) found that plots grazed at lower intensity contained more signs of vole Microtus spp. presence than did plots grazed at higher intensity. After four years, a greater proportion of surveyed quadrats contained signs of vole presence in plots grazed at lower intensity than in plots grazed at high intensity (data not reported). Twelve plots were established (in three sets of four) on a historically grazed salt marsh. From 2010, six plots (two random plots/set) were grazed at each intensity: low (0.5 animals/ha) or high (1.0 animal/ha). Grazing occurred in summer (June–October) only. Half of the plots were grazed by cows and half by horses. In October 2013, sixty quadrats (2 m2) were surveyed in the higher elevations of each plot for signs of vole presence (runways, fresh plant fragments or faecal pellets). Some flooded quadrats were excluded from the analysis.

    (Summarised by: Nigel Taylor)

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