I saw a snippet on TV (Kate Humble (programme about Wales) on the National Trust letting Great Orme for £1 a year to a farmer who would graze it with sheep in the traditional way, as this suppresses the coarse grasses and allows the finer ones and wild flowers to have enough light to grow and set seed, which encourages insects including rare butterflies, which encourages wildlife including rare birds ..... Also reading Rosamond Young's The Secret Life of Cows which points out that cows grazing traditional meadows will have a much more varied diet that those on rye-grass-and-white-clover mix, with the opportunity to get two elements in their diet which are only available from grass that's set seed.