岷江源区生态群落空间分布及植被恢复

The Spatial Distribution of Ecological Community and Vegetation Restoration in the Source Region of Minjiang River

为保护岷江地区生物多样性,恢复退化的植被本底资源尤为关键。笔者按岷江源区河谷植被退化梯度及流域-海拔梯度,设置"U"或"M"型临时观测样带,并采用样方法对乔木、灌木及草本进行详细调查。结果表明:(1)沿岷江源区河谷(流域-海拔梯度)剖面线设置"U"或"M"形样带3条,对植被和环境因子进行调查,共计73个样方316个物种,创建样地-物种数据库,运用DCA和DCCA排序及多元回归方法,得出DCA排序在AX1轴上,海拔由上到下逐渐增高,植被沿海拔分布的梯度格局得到很好地体现,在山体中部,植被结构出现多层,乔木种多为岷江冷杉和云杉及少量白桦。(2)用DCA分析法对岷江源区73个样方内316种植物进行排序分析,计算各群系DCA排序轴的平均值,结合前文DCA排序结果,即DCA排序轴反映的生态梯度关系及植物生理特征和生态适应性特点,得到岷江源区植被群系的演替关系为:云杉、冷杉针叶林—鲜卑花和绣线菊灌丛—锦鸡儿和小檗灌丛—白茅草甸。(3)在满足垂直分布规律的条件下,为植被不同生长型选择恢复的目标群落及物种,结果如下:①亚高山针叶林带:岷江冷杉+(峨眉蔷薇+金背杜鹃+冰川茶镳子)+(细弱草莓+东方草莓+丝叶苔草),云杉+(峨眉蔷薇+窄叶鲜卑花+沙柳)+(细弱草莓+丝叶苔草+陕甘蓼+东方草莓);②高山灌丛带:高山柳+披针苔草,窄叶鲜卑花+洽草,高山绣线菊+丝叶苔草,甘青锦鸡儿+密生苔草;③高山草甸群落:白茅草甸,丝叶苔草草甸。在植被恢复期,应该大力发展乔灌草的多层次、多物种、多结构的混交群落结构,提高植被抵御外界破坏的综合能力,同时施以各种工程措施,使得岷江源区生态系统得到逐步恢复。

In order to protect the biodiversity,the restoration of the degraded vegetation is indispensable.A ccording to the gradient of the altitude in the source region of Minjiang River,three transects of vegetationp lots were settled to investigate the facts of the vegetation and the environment.Then two databases of the sites and species were established.Then the regression analysis between the ordination axes and environmentale lements were applied.The results suggested that：On the first axis scores of DCA,the altitude was increasingg radually from up to down,the gradient pattern of altitude distribution of vegetation got to embody.In the middle of mountain body,there were many layers of vegetation structures,and the main arborous species were Abies faxoniana,Picea asperata and small mount of Betula platyphylla Suk.Using the DCA analysis to sort,the author analyzed the 73 quadrats and 316 plant species,calculating out the average values of the axis scores of DCA of each formation,combined with the result of DCA ordination in previous paper,namely,the ecologicalgradient relationship and physiological characteristics of vegetation and ecological adaptability which the axiss cores of DCA showed,we got the succession relationship of vegetation formation of the source region of Minjiang River：Ass.Abies,Picea-Ass.Sibiraea angustata,Spiraea spp.-Ass.Caragana spp.,Berberisa murensis-Ass.Imperata cylindrical.The objective community and objective species were chosen to restore fort he different growth form of vegetation.Under the conditions of the vertical distribution regularity was obeyed,the objective community of restoration in subalpine coniferous forest belt was：Ass.Abies faxoniana＋（Ass.Rosao meiensis＋Ass.Rhododendron clementinae＋orientalis Ribes glaciale）＋（Ass.Fragaria gracilis＋Ass.Fragaria＋A ss.Carex capilliformis）;Ass.Picea asperata＋（Ass.Rosa omeiensis＋Ass.Sibiraea angustata＋Ass.Salixc heilophilla）＋（Ass.Fragaria gracilis＋Ass.Carex capilliformis＋Ass.Polygonum hubertii＋Ass.Fragariao rientalis）.The objective community of restoration in the alpine scrub belt：Ass.Salix cupularis＋Ass.Carexl anceolata,Ass.Sibiraea angustata＋Ass.Koeleria cristata,Ass.Spiraea alpina＋Ass.Carex capilliformis,Ass. Caragana tangutica＋Ass.Carex crebra.The objective community of restoration in the alpine meadow：Ass.Imperata cylindrica＋Ass.Carex capilliformis.During the time of vegetation recovering,we should develop them ulti-hierarchial classification,multi-species,multi-structure community structure of trees,brushes andg rasses,increase the comprehensive ability of vegetation resisting external destroying,at the same time,taking kinds of engineering measures to restore the ecosystem of the source region of Minjiang River gradually.