Danish grasslands are behaving strangely and researchers don't know why

Nature slowly begins to change if meadows and grasslands are allowed to grow wild without human interference or grazing animals. Weeds do well with disturbance from cows and sheep that graze and tramp on the soil, for example. However, weeds have a harder time if there is no disturbance, and other plants then begin to take their place. The competition for sunlight and good soil increases.