滇西北亚高山不同退化林地植被与土壤养分特征

Characteristics of vegetations and soil nutrients on subalpine degraded forestlands in Northwest Yunnan

将滇西北亚高山退化林地划分为5个不同退化阶段,采用样方调查法研究其群落植被和土壤养分变化规律。结果表明:在以黄背栎为演替顶极的退化林地中,随草本群落→灌木群落→乔木群落的恢复演替过程,群落中木本植物的科、属、种均有不同程度的增长趋势,其中灌木种增长最大;在功能群组成比例变化上,1年生草本在早期占较大比例,随后与多年生草本一起逐渐减少;灌木和乔木种所占比例在各恢复阶段中一直处于上升趋势,并在针阔混交林内达最大比例,以后略为减少并趋于稳定。此外,各阶段群落内土壤pH值有所下降,土壤有机质、全氮、水解氮及速效钾均呈现增长趋势,但速效磷含量的变化没有规律性。

The sub-alpine degraded forestlands in Northwest Yunnan were categorized as five degradation stages, and the characteristics of the vegetations and soil nutrients on each type of the forestland were studied by the method of sampling plot. The results showed that on the degraded forestland with Quercus pannosa as the climax, the numbers of woody plant family, genera and species increased with the succession series from herb to shrub to tree communities, and shrub species had a particularly noticeable increase. As for the proportions of plant functional groups, annual herbs occupied larger in early stage but declined gradually along with perennial plants in middle and late stages, while shrubs and trees had an increasing trend through out all stages, being reached the greatest at needle and broad-leaved mixed forest stage and then declined to some extent until steady. In different stages, soil pH had some decrease, soil organic matter, total N, hydrolysable N and available K had an increasing trend, while soil available P had no definite change pattern.