Population differentiation in grassland vegetation

摘要: Most temperate grasslands are the result of human impact on, and management of, former forests woodlands. They came to existence, remain in their present state, because disturbance; few natural occur zone Europe. I will use term disturbance here as ‘the change conditions interfering with a normal functioning given biological system’ (cf. Chapter 1). ‘Disturbance’, other terms, may have different meaning at level cell, individual, population, plant community ecosystem, but shall consider mainly populations. Cyclic events, such seasonal changes temperature or precipitation, not be considered per se disturbance. In agreement Hedrick (1984) population defined ‘a group interbreeding individuals same species that coexist together time space’.