放牧草地群落的冗余与补偿

Redundance and Compensation of Grazed Grassland Communities

放牧草地群落的冗余与补偿是植物与环境、植物与动物协同进化的产物，是在草地实现其功能最大化过程中形成的。不同放牧强度下，可有三种形式的冗余存在，即生长冗余、组分冗余与内禀冗余。草地群落冗余的原因，有过度放牧、过轻放牧及草地群落固有的特性所导致。一定环境条件下，冗余与补偿是互逆的过程，补偿生长是冗余产生的条件，而冗余是补偿生长的必然结果。削减冗余可望获得草地产量的补偿或超补偿，从而提高草地的优良牧草产量。实现牧草生长的补偿作用需要一定的条件，如草地群落功能不饱和、牧食后足够的恢复生长时间、充足的水分养分条件、毒害草较弱的竞争能力以及恢复生长的基础生物量等。最佳的利用方式是放牧草地群落只有内禀冗余存在，而没有生长冗余和组分冗余。

Redundance and compensation of grazed grassland communities is the outcome of co evolution between plants and the environment, as well as plants and animals, during their functional maximisation. There exist three types of redundance under different grazing intensities: growth, compositional and intrinsic redundances. Under certain environmental conditions compensational growth is the condition for the occurrence of redundance, while the latter is a certain result of the former. Reducing redundance can lead possible compensation or over compensation in the yield of quality forages. The realisation of compensation needs some necessary conditions, such as enough time for plant re growth, soil moisture and nutrients, weak competition from pest plants and the availability of basic biomass to support re growth. The ideal way of grassland utilisation is to maintain a state in which there exits only intrinsic redundance in grassland communities.