基因组学与应用生物学

常绿阔叶林退化生态系统恢复的关键是物种多样性的恢复发展。对大明山区常绿阔叶林退化生态系统植被恢复过程物种多样性的发展趋势和速度进行了研究。结果表明 :1.大明山中山区和低山丘陵区退化生态系统恢复过程中物种多样性的发展速度存在很大差异。中山区采伐森林后炼山种植杉木 ,经过 2 0年的自然恢复 ,在 60 0 m2的调查面积里出现了 178个物种 ,其中乔木层就有 58个物种 ,并且 2 0年左右就能形成以阳性阔叶先锋树种与中生性阔叶树种为共优势的森林群落 ,大约 60～ 10 0年就能形成中生性的常绿阔叶林。而在低山丘陵区 ,常绿阔叶林退化生态系统恢复过程物种多样性的发展速度相当缓慢 ,恢复期为 2 0～ 30年的群落 ,在 4 0 0 m2 样地上仅出现 2 2个物种 ,乔木层只有 3个物种 ;而且由于人为的干扰不断 ,这一地区的马尾松林很难恢复到地带性的常绿阔叶林 ,只能发展成相对长期稳定的人为偏途顶极。 2 .在退化生态系统的恢复过程中 ,物种数量的变化呈前期迅速增加 ,中期减少 ,后期维持一定水平的发展趋势。 3.单位面积上个体数量的变化在群落的不同层次表现不同 ,乔木层在 1～ 2 0年间个体数量呈递增趋势 ,2 0年后表现为递减趋势 ;灌木层的个体数呈不断增长的趋势 ;而草本层的个体数量则呈非线性发展。4 .β

The key to the recovery of evergreen broad leaved forest degradedecosystem is the restoration and development of species diversity.The development tendancy and rate of species diversity in vegetation restoration process in the degraded ecosystem in evergreen broad leaved forest in Daming Mountain have been studied.The main results are as follows: 1 .The restoration rate of the species diversity in restoration process in degraded ecosystem are very different between mid- mountain area and low- mountain- hills area in Daming Mountain.In the mid- mountain area,planting Cunninghamia lanceolata after controlled burning.1 78species appeared in 6 0 0 m2 site for2 0 years natural restoration, including5 8species in tree layer. In addition,the forest community which consist of light demanding broad- leaved pioneer trees and mid- tolerance broad- leaved trees only needs about 2 0 years to form,and developed into mid- tolerance evergreen broad- leaved forest need6 0～ 1 0 0 years.The developmental rate of species diversity in restoration process in degraded ecosystem in evergreen broad- leaved forest is very slow in the low- mountain- hills area.In2 0 ～ 30 years restored community,2 2 species appeared in 40 0 m2 site,including only 3species in tree layer.In addition,Pinus massoniana forest in this district was inturbed continually by human actions,it is difficult to recovering but maintains relative stability. 2 .The change of species numbers in degraded ecosystem recovering process tends toward the climax by quick increasing in the early stage(2～ 2 0 years) ,decreasing in the mid- stage (5 0～ 6 0 years) ,keeping up a level in late- stage (over 1 5 0 years) . 3.A change of individual numbers in per unit area is different in different layers of community.Individual numbers of tree layer is increasing in 1～ 2 0 years,and decreasing later. Individual numbers of shrub layer tend to continuous increasing with degraded ecosystem restoration.However,a change of individual numbers in herb layer is nonlinear. 4.By analysingβ diversity index of communities in differenttime and space,itwas found that the species composition of communities develop toward the community composition in the zonal evergreen broad- leaved forest.