Effects of grazing by free-ranging cattle on vegetation dynamics in a continental north-west European heathland

Published source details Bokdam J. & Gleichman J.M. (2000) Effects of grazing by free-ranging cattle on vegetation dynamics in a continental north-west European heathland. Journal of Applied Ecology, 37, 415-431.
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This study is summarised as evidence for the following.

	Action	Category
	Use grazing or alter livestock to control grass Action Link
	Increase number of livestock Action Link

Use grazing or alter livestock to control grass

A replicated, controlled, before-and-after study in 1983-1993 in four heathland sites in the Netherlands (Bokdam & Gleichman 2000) found that grazing to reduce grass cover increased the cover of wavy hair-grass Deschampsia flexuosa and had mixed effects on the cover of common heather Calluna vulgaris, cross-leaved heath Erica tetralix, and purple-moor grass Molinia caerulea. Cover of wavy hair-grass was higher after grazing was introduced than prior to the introduction of grazing (after: 82–91%, before: 51–54%) and was also higher than in ungrazed (after: 23–61%, before: 76–77%). Cover of common heather increased in one of two sites after grazing (after: 22%, before: 0%), while in the other grazed site it was not significantly different when compared to cover prior to grazing (after: 0%, before: 0%). After the introduction of grazing neither cross leaved heath cover (after: 7%, before: 6%) nor purple-moor grass cover changed significantly (after: 37–87%, before: 33–73%). In 1983 the grazed areas were stocked at a density of 0.2 cows/ha and fences were constructed in parts of the sites to exclude livestock. In 1983–1993 a small number of trees were cleared from the sites. Point quadrats were used in each area to assess vegetation cover (number of quadrats not specified).

(Summarised by: Phil Martin)
Increase number of livestock

A replicated, before-and-after trial in 1983–1993 in two heathlands in the Netherlands (Bokdam & Gleichman 2000) found that cattle grazing increased cover of heather Calluna vulgaris in one of two sites, the cover of wavy-hair grass Deschampsia flexuosa in one of two sites, and, despite an initial increase, it reduced the number of plant species in two of two sites. After ten years and in one heathland, heather cover increased from 20% before grazing to 95%, while the cover of wavy hair-grass did not change significantly (before: 0% cover, after: 1% cover). However, in another heathland, heather cover decreased from 69% before grazing to 59% ten years later, while the cover of wavy hair-grass increased from 16% to 60% over the same period. In both sites grazing increased the number of plant species from 3–5 species/plot before implementation of grazing, to 9–11 species/plot after 5 years, followed by a decline to 5–9 species/plot 10 years after grazing. In 1983, cattle were introduced in the two heathlands (approximately 0.2 cows/ha). Three 25 m² plots were located in one heathland and six in the other. Vegetation cover was recorded in each plot annually between 1983 and 1993.

(Summarised by: Phil Martin)