渝西地区火烧迹地不同植被恢复方式下的物种多样性动态

Dynamics of Species Diversity of Burn Blanks under Different Restoration Ways in Western Chongqing

以“空间序列”代替“时间序列”的方法对渝西地区不同恢复方式下不同年龄的火烧迹地进行了调查研究,结果表明:火烧迹地的植被均匀度、丰富度和Shannon-Wiener指数等随恢复年限的变化曲线在人工恢复和自然恢复两种情况下有很大差异.实验中看不出两种恢复方式的不同是否能决定群落最终的物种多样性水平,但是不同的恢复方式可以加快或减缓物种多样性恢复的过程.实验还表明:在人工恢复的35年以内,多样性的恢复是一个“S”形变动的过程.人工恢复可以缩短灌木丛阶段的年限,加快乔木层的建成,同时促使该类型林区更长时间的停留在针叶林阶段,推迟该林区向顶级群落的演替进程;在自然恢复的40年以内,多样性的恢复是一个逐渐上升的过程,在最初的8年以内,其多样性不如人工恢复,但在恢复40年左右的时候,其多样性却可以达到一个比人工恢复高很多的水平.

Dynamics of species diversity on the burn blanks with different times after burning was studied in western Chongqing, using the method of ＂the sequence of space instead of the sequence of time＂. Significant differences were observed in Evenness curve, Richness curve, and Shannon-Wienner index curve between the rehabilitated communities under artificial management and in nature. While it remains unclear whether different restoration ways can lead to different ultimate species diversity of these communities, the results do indicate that different restoration ways can accelerate or delay the rehabilitated process in the studied communities. Species diversity curve presented an S-shape under 35-year artificial restoration and in the rehabilitated communities the shrub stage was shortened, the tree layer was built in relatively shorter time, the conifer tree stage lasted longer, and the succession process to the climax community was delayed. In contrast, in the communities by natural restoration, the species diversity was lower than in the communities by artificial restoration in the first 8 years, but after 40 years＇ restoration, it climbed to a much higher level than that in the communities by artificial restoration.