Effects of vegetation cover on recruitment of Ulmus pumila L. in Horqin Sandy Land, northeastern Chi

来源 :Journal of Arid Land | 被引量 : 0次 | 上传用户:zbt_25
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Understanding the effects of vegetation cover on seedling survival is helpful for promoting vegetation restoration in environmentally fragile zones. This study was conducted in the desertified, moving sand dunes of Horqin Sandy Land, Inner Mongolia, northeastern China. We hyphothesized that(1) seed density(i.e., number/m2) increases as vegetation cover increases, and(2) there will be more surviving seedlings in locations with higher vegetation covers. Total vegetation cover and initial densities of seeds, germinated seeds and surviving seedlings of Ulmus pumilia were evaluated under various vegetation covers in trying to clarify the effects of vegetation cover on the early stages of the plant life history. In agreement with the first hypothesis, initial seed densities were greater(P<0.05) under higher vegetation covers. The relationship between vegetation cover and initial seed density was represented by a quadratic regression, where a threshold occurred with a vegetation cover of 36%(P<0.05). The higher total vegetation covers, however, did not result in increased densities of germinated seeds(P>0.05), which on average represented 16.7% of initial seed densities. Even more, three months after the study initiation, total vegetation covers were similar(P>0.05) at all positions in the dunes, and they determined a similar number(P>0.05) of surviving seedlings at those positions(i.e. the second hypothesis had to be rejected). The mean number of seed- lings that survived at all positions was only 4.5% of germinated seeds. The number of surviving elm seedlings(0 to 1.7 seedlings/m2) under various vegetations covers(12.2% to 20.8%) at all dune positions by late summer would most likely not contribute to vegetation restoration in the study area. Understanding the effects of vegetation cover on seedling survival is helpful for promoting vegetation restoration in environmentally fragile zones. This study was conducted in the desertified, moving sand dunes of Horqin Sandy Land, Inner Mongolia, northeastern China. We hyphothesized that (1) seed density (ie, number / m2) increases as vegetation cover increases, and (2) there will be more surviving seedlings in locations with higher vegetation covers. Total vegetation cover and initial densities of seeds, germinated seeds and surviving seedlings of Ulmus pumilia were evaluated under various vegetation covers in trying to clarify the effects of vegetation cover on the early stages of the plant life history. In agreement with the first hypothesis, initial seed densities were greater (P <0.05) under higher vegetation covers. The relationship between vegetation cover and initial seed density was represented by a quadratic regression, where a threshold occurred with a vegetation cover of 36% ( The higher total vegetation covers, however, did not result in increased densities of germinated seeds (P> 0.05), which on average represented 16.7% of initial seed densities. Even more, three months after the study initiation, total The mean number of seed-type seeds in the dunes, and they determined a similar number (P> 0.05) of all surviving seedlings in those positions (ie the second hypothesis had to be rejected) lings that survived at all positions was only 4.5% of germinated seeds. The number of surviving elm seedlings (0 to 1.7 seedlings / m2) under various vegetations covers (12.2% to 20.8%) at all dune positions by late summer would most likely not contribute to vegetation restoration in the study area.
其他文献
本试验利用自制的地质力学模型材料(MSB),在窑洞式地下厂房的立式平面应力模型的周边上,按实际主应力方向进行加载。成功地模拟了原始地应力场,得出了洞室在实际开挖过程中围
正在施工的清江隔河岩工程,其重力拱坝高151米,电厂装机容量为120万kw。本文介绍了变形监测系统的总体设计,包括监测控制网、坝体及坝基的变形监测及电厂的监测等项,并介绍了
(一)问题的提出甘肃省处于祖国大陆腹地,受季风的影响,大部分地区干旱少雨,水资源缺乏,成为全国一个以干旱著称的省分。建国以来,我省修建了一大批水利设施,促进了农业生产
英国菲利克斯托沃港的运作与海关管理宋君涛(译)本文是英国海关应世界海关组织信息中心的邀请而作。尽管菲利克斯托沃港的海关工作并不能代表整个英国海关的情况,但是现代海关制
节庆活动作为促进销售的一种重要手段,已为零售业广泛接受。在大商厦林立的商业区,三天一小节,五天一大节,节庆活动接连不断,鼓乐争鸣,热闹非凡。然而透过热闹的表象,真正办得深入人
日本四面环海,具有发展海水抽水蓄能电站的优越地理条件。60年代以来,政府机构和电力公司就一直进行着有关调查和可行性研究工作。然而,由于涉及使用海水的某些技术和环境问
何家栋日前在山西发展导报上撰文,文章指出中共十五大政治报告提出要“维护国家经济安全”后,颇有一些人拿过来大作文章。有人以此来反对所有制改革,认为外资和非公有制企业
建国以来,黄河干流上先后兴建了龙羊峡、刘家峡、盐锅峡、八盘峡、青铜峡、三盛公、天桥和三门峡等大型水利枢纽工程,支流上的水利水保工程也有很大发展,这些工程对黄河来水
新颖的橱窗陈列会吸引顾客的眼神。激起顾客的购物欲望。富于影响力及实力的现代眼镜店。都无不重视对眼镜店橱窗展示的设计。因为,明智的眼镜店领导者都会懂得橱窗是眼镜店
本文简述了混凝土面板堆石坝的发展及目前国内外的应用现状。并对这种结构的有限元分析方法以及目前经常采用的几种非线性模型的特点作了阐述。采用自编的静、动力分析程序,