Facilitation of red deer grazing by cattle and its impact on red deer performance.
Cattle were removed from the Isle of Rhum, Scotland, in 1957. Cattle were reintroduced into one area of the island in 1970 and grazed on areas occupied by red deer (Cervus elaphus). Winter use by cattle of pasture dominated by Molinia caerulea resulted in greater biomass and availability of green grass in the spring than in ungrazed areas. In the spring, deer preferentially grazed areas that had been grazed by cattle the previous winter. There were more calves per hind in the area of the island grazed by cattle than in another area which was relatively unaffected by cattle grazing. Hind and stag weights were not affected by the reintroduction of cattle. The implication of these results is that cattle could improve forage availability to red deer and possibly sheep over large areas of north-west Scotland.