中国、蒙古国草原(Steppe)对比考察项目   相关图片  论文集

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内蒙古乌拉盖湿地中下游植被退化演替状况的分析*

——内蒙古东乌旗乌拉盖湿地植被生态考察报告

 

苏布达1** 易津1 陈继群2 包秀霞1 萨那斯琴1 文都日乐1

1 内蒙古农业大学  呼和浩特 010019;   2 曾经草原网站  北京 100088

 

摘 要 20089月对内蒙古锡林郭勒盟东乌旗乌拉盖湿地中下游、下游退化草原植被进行生态考察,以期对湿地生态损伤评估和植被演替趋势分析提供依据。该区域涉及6个嘎查的草原面积合计252580.1 hm2 ,其中湿地面积71000 hm2 ,占总面积的28.1%,乌拉盖湿地植被退化速度十分迅速,目前湿地植被几乎全部消失,荒漠化和盐碱化程度达到湿地面积的80%以上,在乌拉盖河截流5年内已经从草原湿地植被变为碱蓬盐化草甸植被和盐漠化裸地,植被性质发生了重大变化,主要表现在原生植被的建群种和优势种基本消失,植被高度和盖度迅速降低,原生植被群落重要值减少,次生植被群落重要值增加;荒漠化程度主要表现在土壤沙化和盐碱化,盐生植被和沙生植被大量出现,更重要的是大面积的裸地已经成为草原沙尘暴产生的主要原因,由于湖泊干涸沙化,进而使周边草原产生严重次生盐漠化,如果不及时治理,沙化面积将每年以15~20%的速度向湖东南地区蔓延,其荒漠化危害会更加严重。

本考察采用植被调查和社会调查结合进行,植被调查采用样线样方法,在湖区不同的方向共选取17条样线,测定了176个样方,植被考察分析结果表明:(1)该地区原生植被类型主要有芦苇湿地草甸草原和大针茅-羊草-线叶菊典型草原2种类型;次生植被类型主要有碱蓬盐化草甸1种;共出现11个植物群落类型;不同植被、群落间的平均盖度、高度和重要值差异显著;(2)次生碱蓬盐化草甸植被主要分布在湖心区,由于乌拉盖河水被上游水库截流后,湖心区土壤大量裸露,湖心出现大面积碱蓬盐化草甸次生演替植被和重度盐碱化裸地,植被退化程度十分严重。(3)芦苇湿地植被主要分布在近湖区,有6个群落类型,其中退化演替群落5个,占80%以上;退化演替群落中碱蓬群落、盐生砂引草群落的重要值都显著高于原生植被中的芦苇群落;5个退化群落重要值合计(254.5)也显著高于原生植被芦苇群落(31.8),说明中生和湿生植物为建群的草原湿地植被已经逆向演替为盐生植物建群的盐漠化草甸。(4)大针茅-羊草-线叶菊典型草原类型主要分布在远湖区,出现有5个群落类型,其中退化演替群落有1个,占20%;植被发生轻度退化,主要表现为植物盖度、高度和种类减少,但是典型草原植被的原生植被的基本特征还具备,说明其退化程度较低。(5)植物生物多样性调查结果表明芦苇湿地植被不同群落植物数量都较少,生物多样性严重减少,按照生活型比较,一年生草本植物数量和比例明显高于多年生草本植物,并且还出现超旱生植物白刺,说明该群落退化程度严重,已经具有明显荒漠化特征;而大针茅-羊草-线叶菊典型草原植被类型中多年生植物数量和比例明显高于一年生草本植物数量,退化程度较低。调查显示乌拉盖河流域植被退化的原因主要是上游水库截流人为人素所致,其次与气候变暖,降水减少有关。

关键词:乌拉盖湿地;退化草原;植被特征

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* SEE环保NGO基金项目资助(2008-2009

** 苏布达(1984--)女,蒙古族,内蒙古农业大学牧草生理生态学硕士研究生;

***通讯作者:易 津,(1951-)女,四川成都人,教授,博士生导师 , 主要从事牧草生理生态研究

 

Analysis of Vegetation Degeneration Succession in Middle and Lower Reaches, Wulagai Wetland of Inner Mongolia

Investigation Report of Ecology in Wulagai Wetland of Inner Mongolia

                        Subuda1, Yijin1, Chenjiqun2, Baoxiuxia1, Sanasiqin1, Wudurile1

1 Inner Mongolia Agriculture University, Huhhot 010019; 2 'Echoing Steppe' website, Beijing 100088

Abstract: We investigated vegetation characteristics in middle, lower and lower reaches, Wulagai wetland of Inner Mongolia on Sep.2008. It provided basis for the assessment of ecological damage and tendency of vegetation succession. Grassland of 6 villages is aggregated 252580.1 hm2, wetland are is 71000 hm2, it about 28.1% of the total area. Vegetation degeneration is speedy, now wetland vegetation is almost disappeared, desertification and salinity degree more than 80% of the wetland area. Wetland vegetation have changed Suaeda glauca salt vegetation and bare land, constructive and dominant species are basically disappeared, vegetation height, coverage and important value is decreased, important value of secondary community is increased.  Desertification and salinization of soil, salt and desert vegetation are appeared in this area. Bare land caused primary reasons of sand storm, because lake is dried and deserted lead to grassland vegetation is secondary salt-desertification. If we untimely control desertification that harming is more serious.

     We adopted methods of sample line, square and chose 17 lines, 176 square. Result showed that (1) Native vegetation type has Phragmites australis meadow steppe and Stipa grnadis-lemus chinesens-Filitolium sibiricum typical steppe, second vegetation type is Suaeda glauca salination meadow steppe. There are 11 community types. Coverage, height and important value are significant differences among the communities. (2) Lake has Suaeda glauca salination meadow steppe in the center. Because upper reaches reservoir in Wulagai river is closed, vegetation degeneration is more serious. (3) Phragmites australis wetland in nearby the lake have 6 communities, degeneration community is 5, more than 80%. Community important value of Suaeda glauca and Messerschmidia sibirica is higher than Phragmites australis. Important value of five degeneration communities is higher than native community. The result showed that steppe of salination and desertification has replaced wetland vegetation. (4) Stipa grnadis-lemus chinesens-Filitolium sibiricum typical steppe in the far lake that it has 5 communities. Moderately degeneration community is one, ratio is 20%. Coverage, height and species of native vegetation basically are not changed, grassland degeneration is lower. (5) Result of plant biodiversity showed that plant quantity is less, biodiversity is seriously decreased, annual plant ratio is higher than perennial plant in Phragmites australis wetland. At the same time, the area has arisen strong xeric plant, Nitraria tangutorum. It expressed that community degradation is serious and existed desertification characteristics. Perennial quantity and ratio are higher than annual, degradation degree is lower in Stipa grnadis-lemus chinesens-Filitolium sibiricum typical steppe. Reasons of vegetation degradation in Wulagai river is lead to upper reaches reservoir closure, climate changes and precipitation decrease. 

Keywords: Wulagai wetland; Degeneration steppe; Vegetation characteristics

* foundation item: NGO project of SEE environmental protection2008-2009

** Author introduction: Subuda1984--FemaleMongolianMaster student.