【作者】 严代碧；

【导师】 马钦彦； 王金锡； 慕长龙；

【作者基本信息】 北京林业大学 ， 生态学， 2006， 博士

【摘要】 中国的干旱河谷区分布在岷江上游﹑金沙江上游﹑大渡河上游﹑雅砻江上游,以及嘉陵江的支流白龙江流域等地区,集中分布于岷江、鲜水河、雅砻江及金沙江等流域中段,以茂县、汶川、金川、丹巴、乡城和巴塘为代表,约30万hm2,由于山体高差悬殊,其分布幅度差异甚大,近代以来随着人口的急剧增长,人类对土地压力增大,使该区域的植被和森林遭受严重破坏,过度放牧,毁林开荒,使干旱河谷的范围向上、向下不断扩展,致使该区域形成了荒漠景观。加之该区域地层破碎,坡度大,水土流失非常严重。据统计,岷江流域年土壤流失沙量达5000万T,占长江三峡口输沙量的1/10。因此,加强该区域的植被恢复,改善生态环境,减少灾害是刻不容缓的重要课题。通过对岷江干旱河谷区植物群落区系、群落物种多样性、生物量等特征,干旱河谷地区区划与树种选择,以及造林技术等进行系统研究,研究结果表明:(1)岷江上游杂谷脑河干旱河谷属干暖河谷,该区干旱河谷灌草丛植被分布于河面以上海拔高度2000米以下的河床两侧山坡范围内,不同种类的灌丛分布断续,主要呈随机分布和集群分布,很少呈均匀分布;灌木基本上为落叶种类,为适应这恶劣的环境,灌木表现出一系列的趋同现象,如丛生、根深、叶小、具刺、被毛、低矮或匍匐的性状;群落层次和组成结构单一,群落类型具有多样性;该区有维管植物253种,隶属于57科175属,植物种类贫乏,有明显的重点科;种子植物区系以温带成分占优势,与热带成分有紧密的联系;植被具有荒漠化半荒漠化性质,且程度在加重。(2)岷江上游杂谷脑河流域干旱河谷区植物种类较少且具有荒漠化半荒漠化性质,阴坡植被明显比阳坡丰富;该区植被及其生物多样性指数在阴坡和阳坡都表现出随海拔升高而增大的趋势;岷江上游杂谷脑河干旱河谷区典型地段植被坡性特征非常明显,阴坡和阳坡的物种丰富度、均匀度和多样性差异显著,阴坡植被无论是灌木还是草本的丰富度、均匀度、Simpson多样性指数和Shannon-Wiener指数均大于阳坡植被,且阴坡上部有乔木层分布,而阳坡则无。此特点显示岷江上游杂谷脑河干旱河谷区阴坡植被恢复较阳坡容易。(3)岷江上游干旱河谷灌丛阴坡灌丛的平均总生物量为30151.72 kg·hm-2,各层生物量从大到小依次为∶灌木层﹥草本层﹥地被层﹥枯落层,其生物量占总生物量的更多还原

【Abstract】 Chinese arid valley region mainly distributed in upper reaches of Minjiang river, Jinshajiang river, Yalongjiang river and reaches of Bailongjiang river which is a branch of Jialingjiang river and they also mustered in Minjiang river, Xianshuihe river and Yalongjiang river middle reaches, which typically show in Maoxian county,Wenchuan county,Jinchuan county, Danba county, Xiangcheng county and Batang county. The area of arid valley reach 300,000 hm2, and the arid spectra of each valley is variety with the varied height of mountains. Currently with the rapid increase of population, and the enlarging stress of land use, the vegetation and forest were destroyed drastically, and then the spectra of rid valley extended upper and down along the slope of mountains and then desert landscape appeared in the region with the overgraze and the action of destroy forest for cultivation. The water and soil erosion in this region is graveness because of crashed stratum and steep slope. Erosion sand in the Minjiang river catchment, the one tenth of sand in Three Gorge of Yangtze River, reached 50,000,000 Ton, so it was urgent to restore the vegetation, improve the environment and decrease the disaster in this region. Through systematic research of the character in plant community flora, community species diversity and biomass and with the layout and species choose and silvicutural technology in the arid valley in Minjiang river drainage area, the result showed that:The arid valley of Zagunao river belongs to warm-arid valley at the upper reaches of Minjiang river, its vegetations distribute on the mountain slope of both更多还原