Studies in sheep populations and environment in the mountains of north-west Wales. 2. Contemporary distribution of sheep populations and environment.
Average summer sheep population densities in ewe units/ha at 56 sites in Snowdonia in 1957-68 were 4.99-10.65 on herb-rich Agrostis tenuis/Festuca ovina, 1.56-6.4 on A. tenuis/F. ovina/Nardus stricta, 2.47-5.44 on N. stricta/F. ovina, 2.12-5.02 on Molinia caerulea/Juncus spp., 0.34-2.89 on Vaccinium myrtillus/Calluna vulgaris and 0.37-0.99 on scree vegetation (open A. tenuis/F. ovina); the low figures were for a high-rainfall area and the high ones for a medium-rainfall area. Higher densities, up to 18.17/ha, were found on sites of former cultivations. Population density was inversely related to rainfall, acidity of soil parent material, altitude and the trend from species-rich to acidic grassland, moorland and heath. Poorly drained soils derived from acidic parent materials tended to bear high population densities.