茂兰喀斯特森林演替阶段不同小生境的小气候特征

Microclimate Characteristics of Different Microhabitats in Successional Stages of Maolan Karst Forest

探讨了茂兰喀斯特森林不同演替阶段群落不同小生境的气温、湿度、光照强度和土壤温度的日变化特征,结果表明:各演替群落内大气温度和光照强度随演替逐渐降低,且降幅趋缓;空气相对湿度却随着群落演替而逐渐升高,但变幅减缓;5～20cm土壤温度随演替进展逐渐降低,随着土层深度的增加土温亦呈下降趋势且降温幅度减缓。以乔木林的生态环境和小气候条件最佳,次生林和灌木林次之,草坡最差。乔木林气温、湿度、辐射等变化缓和,有利于植被生长使群落稳定地向顶级演替。草坡各气象要素均表现剧烈变化,有待于经历较长的时间演替改善,才能到达顶级群落。不同小生境之间,不论温度、辐射或相对湿度都有较大差异。土面、石沟的生态气候条件较好,光、热、湿变化缓和,有利于植物生长;石面、石缝的辐射、温度、湿度变化剧烈,植物生长受到制约。

The main climate factors,such as air temperature,relative air humidity,light intensity and soil temperature were studied in different microhabitats of different successional stages in the Maolan karst forest,Guizhou Province.The results showed that as the communities developed,air temperature and light intensity in different successional stages tended to decrease,and their variations became small;relative air humidity was increasing and its variation became small with the evolution.The soil temperature at the depth of 5~20 cm dropped with the evolution of the communities and the soil temperature decreased with depth.Ecologic environment and microclimate conditions of primary forest were best,those of secondary forest and shrubberies ranked the second,and the conditions of herbage were worst.Variations in temperature,light intensity and relative air humidity of primary forest were mitigable,which is beneficial to the growth of vegetations and the development of communities.However,variations in microclimate conditions of herbage were violent,it must take a long time to finish ecological succession.Significant differences in ecologic microclimate were noticed for different microhabitats.The ecologic microclimate conditions of Earth's flatland and gully developed very well.The light,temperature and humidity changed mildly,soil surface was suitable for plant growth.For rocky flatland and crevice,the temperature,light intensity and relative air humidity changed dramatically and plant growth was restricted.