漓江上游红壤侵蚀区不同植被群落环境因子差异

 为给漓江流域红壤侵蚀区植被恢复和重建提供科学理论依据,研究漓江上游流域红壤侵蚀区主要植被类型群落内小气候环境因子的差异,采用“以空间导时间”的方法分析植被退化过程中主要环境因子的变化。在植被退化的过程中,由于植被群落结构和物种组成的退化,主要的小气候环境因子均发生比较明显的变化,主要表现:针阔混交林类型群落和常绿阔叶林类型群落照度的垂直差异和时间变化非常小,而草丛群落以及灌丛群落的照度存在比较明显的垂直差异,光照强度随高度的增加而增大,在150cm以上的高度,照度的时间变化比较明显;针阔混交林类型群落和常绿阔叶林类型群落气温的垂直变化非常小,一般在0．5℃以下,在监测时段内其气温的变化幅度在2℃左右,而草丛群落和灌丛群落气温的垂直变化和时间变化相对较大,气温垂直变化的幅度最大可达到6℃; 针阔混交林类型群落和常绿阔叶林类型群落空气相对湿度的垂直变化不明显,变化范围一般在5％以下,草丛群落和灌丛群落空气相对湿度的变化幅度比较大,最大可达25％;常绿阔叶林类型群落的土壤内部温度变幅最小,在0．5℃以下,而灌丛群落的波动幅度较大,可达8℃左右。总体而言,在植被退化过程中,光照强度、空气温度、土壤温度和气地温差不断增大,空气湿度逐渐降低,同时,主要小气候环境因子的时空波动性从平缓渐趋剧烈。

Differences of environmental factors of different vegetation communities in erosion region of red soil in upper reaches of Lijiang river

In order to provide scientific theoretic basis for vegetation restoration and rehabilitation in the eroded red soil region in the Lijiang basin, the differences of microclimatic environmental factors in the communities of primary vegetation types in the eroded red soil region in the upper reaches of Lijiang basin were compared and studied, and the variations of the main environmental factors in the process of vegetation degradation were also analyzed adopting method of time feature deduced by spatial feature. The results showed that the main microclimatic environmental factors have obvious changes in the process of vegetation degradation because of the degradation of vegetation community structure and species components, which is mainly showed in that. The vertical difference and time variation of light intensity in coniferous and broadleaf mixed forest and evergreen broadleaf forest were smaller than those in grass mass and shrub mass. Light intensity increased with height increasing. In above 150 cm, time variation of light intensity is obvious. The air temperature in coniferous and broadleaf mixed forest and evergreen broadleaf forest had 0-0. 5 ℃ of vertical differences and about 2 ℃ of time variations scale in the monitoring time, and the greater vertical difference and time variation of air temperature occurred in grass mass and shrub mass, and the greatest vertical variation scale was 6 ℃. The vertical variation of relative humidity in coniferous and broadleaf mixed forest and evergreen broadleaf forest was less obvious; whose variation scale was less than 5 % as well as that of soil inner temperature was less than 0.5 ℃. In contrast, those were greater in grass mass and shrub mass, and the greatest variation scale of relative humidity reached 25 % as well as the greatest scale of soil inner temperature reached 8 ℃. In general, the light intensity, the air temperature, the soil temperature and difference of our soil temperature increased continually in the process of vegetation degradation, while the air humidity decreased gradually, and their time and space fluctuant degrees were greater by greater.