Ecological trends and grouse management in upland Britain.
1. This chapter reviews trends in grazing intensity and predation pressure and the possible impacts these will have on the abundance of grouse species and sustainability of grouse management over the next 20 years.
2. On average, managed grouse moors make a financial loss although some of this loss may be set against sporting benefits taken by the land owner. Revenue from driven grouse shooting exceeds that of walked up shooting but requires a higher density of grouse (about 60 km50 was five times lower for ERM protonymphs and adults, but 11 times higher for ERM deutonymphs compared to equivalent TSM life stages. Fluvalinate 2F reduced TSM development from the protonymph and deutonymph stages to a greater extent compared to the ERM. The mortality response to fluvalinate 2F was unaffected by host type (peach or apple) for the TSM whereas ERM mortality was higher on apple compared to peach. TSM dispersal was higher from apple compared to peach whereas ERM dispersal was similar on both host types. Oviposition by both mite species was lower on apple than peach leaves. A 1 h exposure to fluvalinate 2F reduced ERM oviposition for 12 days.