摘要
以民勤绿洲边缘未退化(ND)、轻度退化(SLD)、中度退化(MD)及重度退化(SD)的人工梭梭(Haloxylon ammodendron)林为研究对象,通过野外定点监测与样方调查方法对其植被组成、物种多样性、优势种种群结构变化以及群落间相似性进行了研究。结果表明:(1)ND、SLD及MD林地植物群落灌木层植被均由4种植物组成,SD林地灌木层由3种植物组成,其优势种演替过程为单优种梭梭—共有种梭梭、红砂、白刺—单优种红砂;在草本层中,ND林地出现6种植物,SLD、MD及SD林地均出现9种植物,其优势种演替过程为五星蒿、盐生草—画眉草、黄花矶松。(2)人工梭梭林退化过程中,灌木层优势种梭梭、白刺和红砂种群龄级结构动态变化分别为稳定型—衰退型、增长型—稳定型—衰退型、持续增长型。(3)4种类型林地植物群落物种多样性指标数也发生了不同程度变化,但整个林地植被趋向于更稳定方向发展。(4)4种林地植被群落两两之间的相似性为ND与SD之间的相似性最低,MD与SLD之间的相似性最高。这说明人工固沙林逐渐衰败过程其实质是林地固定改变了林地生境,植物群落发生了由沙生植物群落向沙旱生植物群落演替。因此,在民勤绿洲边缘开展人工固沙林恢复与重建工作时,应将沙旱生植物红砂作为植物材料之一。
Through filed fixed-point monitor and vegetation investigation to the Haloxylon ammodendron plantations with no degradation(ND),slight degradation(SLD),moderate degradation(MD)and severe degradation(SD)growing in the dunes on the edge of Minqin oasis,the vegetation characteristics,species diversity and community similarity were analyzed by calculating the species diversity indices,evenness indices,dominance indices,age structure and similarity coefficient.The results indicated that:There were 4 kinds of shrubs in the regions of ND,SLD and MD respectively and 3 kinds of shrubs in the region of SD,and the replacement procedure of dominant species in shrub layer was H.ammodendron-H.ammodendron,Nitraria tangutorum and Reaumuria songarica-Reaumuria songarica.9 kinds of herbs were growing in SLD,MD and SD woodland respectively and 6 kinds of herbs were growing in the ND,where the replacement procedure of herb dominant species was Bassia dasyphylla and Halogeton glomeratus-Eragrostis pilosa and Limonium aureum.With aggravating of degradation degree of H.ammodendron plantations,the dynamic changes of age structure of dominant species in shrub layer were as follows:H.ammodendron was stability type-recession type,N.tangutorum was growth form-stability form-recession form and R.songarica was sustainable growth.In the process of deteriorating of H.ammodendron plantations,most of plant community diversity indexes were changed,and overall vegetation of the plantations were changing for more stable trend.The plant community similarity coefficients of the forests had significantly difference each other,which the similar degree between ND and SD was the lowest and that between SLD and MD was the highest.It further indicates that the degradation essence of H.ammodendron plantations was the succession from psammophyte community to xerophyte community because of fixation of soil further result in habitat change.Therefore,R.songarica should be as one of main shrubs applied to restoring and reconstructing dune-fixing pantations on the edge of Minchin oasis.
出处
《中国沙漠》
CSCD
北大核心
2017年第6期1135-1141,共7页
Journal of Desert Research
基金
国家自然科学基金项目(31360203
31560128)
甘肃省创新群体项目(145RJIA335)
甘肃省自然科学基金计划项目(1308RJZA267
1308RJYA081)
关键词
民勤绿洲
人工固沙林
龄级结构
物种多样性
群落相似性
Minqin Oasis
dune-fixing plantation
age structure
species diversity
community similarity