In Denmark alone, the number of farms keeping cattle has decreased from 96,000 to 12,000 in the same period, with the average number of cattle in each farm increasing from 12 to 55. If grazing is discontinued or if the grazing pressure is reduced, the natural succession processes will lead to overgrowing of the meadow vegetation with taller grasses, herbs and shrub. The biodiversity of tall-growing vegetation is lower than that in the open, grazed areas. A large number of plant species, bird species and some insects are regularly monitored within their areas of distribution and used as indicators for the occurrence and quality of grazed meadows and grassland.