Individual study: The effect of sheep-grazing management on rejuventation of established heathland and regenteration of heath vegetation on former fertilized pasture land at Westerholt, Drenthe, the Netherlands
Bakker J.P., De Bie S., Dallinga J.H., Tjaden P. & De Vries Y. (1983) Sheep-grazing as a management tool for heathland conservation and regeneration in the Netherlands. Journal of Applied Ecology, 20, 541-560
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Increase number of livestock
A before-and-after study in 1972–1978 in a heathland site in the Netherlands (Bakker et al. 1983) found that increasing the number of livestock resulted in a decrease in vegetation height, but increased grass cover and the number of seedlings of common heather Calluna vulgaris and cross-leaved heath Erica tetralix. After six years vegetation height had decreased by approximately 20 cm when compared to the period before grazing started. Grass cover and the number of common heather and cross-leaved heath seedlings were higher after six years of grazing than before grazing started (no data presented). No statistical tests were carried out in this study. In 1972 sheep were introduced to the area at a density of three sheep/ha. One hundred and nine plots (of undefined size) were placed at the site and vegetation cover was recorded yearly in 1972-1978.
(Summarised by Phil Martin)
Restore/create species-rich, semi-natural grassland
A small study of species-poor grassland in the Netherlands (Bakker et al. 1983) found that preferential grazing by sheep gave rise to a ‘macro-pattern’ of various plant communities absent under a hay-making regime. There were short, heavily grazed patches interspersed with taller, lightly grazed patches, a micro-pattern that tended to be stable after initial establishment. Heavily and lightly sheep grazed areas differed little in plant species composition, but abundances of species differed considerably. Heavily grazed areas were characterized by equal amounts of monocots (mainly grasses) and broadleaved species, had higher abundances of rosette species and, to a lesser extent, greater persistence of perennial rye grass Lolium perenne. Lightly grazed patches were dominated by common bent grass Agrostis tenuis and had a large amount of plant litter. Prior to 1972, the grassland was cut for hay and aftermath grazed by cattle. Sheep grazed part of the grassland (3 sheep/ha) from 1972 in July-December and January-July. After 1980, the area was left ungrazed for 2 months each winter. Vegetation was recorded annually within permanent 2 x 2 m quadrats. Grazing intensity was recorded in February as lightly grazed (>70% litter cover), heavily grazed (<30% litter cover), or intermediate. Species abundance was quantified on a dry weight basis. Vegetation was also mapped from October 1979-1982 in a 10 x 10 m² area and recorded as heavily grazed (<5 cm tall) and lightly grazed (>10 cm tall).