火对香港草地和芒萁群落的影响*

本文研究火对香港草地和芒萁群落的影响。目前遭火烧是不可避免的,但其发生有一定的周期性。火对群落的物种多样性、生物量、第一性生产量和群落的稳定性有重要的影响。

EFFECTS OF FIRE ON THE GRASSLAND AND FERNLAND IN HONG KONG

Fire is an important factor in the natural ecosystem of Hong Kong.Fire and its ecological role in the grassland and fernland are studied.The results show that:(1) Fire is inevitable in the grassland and fernland in Hong Kong.It occurs repeatedly with an interval of 2 or 3 years.Fire is also the most important factor for the stability of grassland and fernland.If the grassland and fernland were protected from hilI fire,they would be probably replaced by shrublad followed by forest.(2)Most of the above-ground biomass was contributed by relatively small numhr of species and the species diversity was reduced,bcause fire induces a stronger development of dominated spedes.In addition,many spedes show some form of adaptation and fire resistance in the communities because fire occurs often.(3) Fire increases net primary production in the grassland and improves the quailty of grasses for animals.However,it decreases net primary production in the fernland and also results in an atypical ratio of below-ground/above-ground biomass of woody plants in both communities.