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Providing evidence to improve practice

Individual study: Effects of reduced grazing on population density and breeding success of black grouse Tetrao tetrix in northern England

Published source details

Calladine J., Baines D. & Warren P. (2002) Effects of reduced grazing on population density and breeding success of black grouse in northern England. Journal of Applied Ecology, 39, 772-780


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Reduce grazing intensity Bird Conservation

A paired sites study on moorland in 1996-2000 in northern England (Calladine et al. 2002) found that the number of displaying black grouse Tetrao tetrix males increased by an average of 5% each year at 10 sites where levels of sheep grazing were reduced, compared with average declines of 2% each year at ten control sites. Changes were most positive in the first years after grazing reduction. The proportion of females with chicks was also significantly higher at treatment sites (average of 54%) than at control sites (32%). However, there were declines in female densities at sites where restricted grazing areas exceeded approximately 1 km2. Grazing was reduced to below 1.1 sheep/ha in summer and 0.5 sheep/ha in winter for at between one and five years on treatment sites. Densities were two or three times higher on control sites.

 

Maintain upland heath/moorland Farmland Conservation

A paired sites study on moorland in 1996-2000 in northern England (Calladine et al. 2002) found that the number of displaying black grouse Tetrao tetrix males increased by an average of 5% each year at 10 sites where levels of sheep grazing were reduced, compared with average declines of 2% each year at ten control sites. Changes were most positive in the first years after grazing reduction. The proportion of females with chicks was also significantly higher at treatment sites (average of 54%) than at control sites (32%). However, there were declines in female densities at sites where restricted grazing areas exceeded approximately 1 km2. Grazing was reduced to below 1.1 sheep/ha in summer and 0.5 sheep/ha in winter for between one and five years on treatment sites. Densities were two or three times higher on control sites.