The Characteristics of Plant Communities Along East Eurasian Steppe Transect

来源 :农业科学学报(英文版) | 被引量 : 0次 | 上传用户:sl604
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
The East Eurasian Steppe Transect (EEST) is the ifrst international transect across regions of middle and high latitudes in the eastern Eurasian steppe. The EEST is an ideal platform for researching the response of Eurasian temperate steppe to global change, because of its integrated gradients of temperature and human activities on a large-scale. In this study, basic characteristics of plant communities along the EEST across a latitudinal gradient was analyzed. According to the survey of 58 sampling sites, there are 140 species belonging to 34 families and 94 genera. Of particular note was the ifnding of Astragalus dalaiensis which has disappeared in the grasslands of China. On the whole, Gramineae plants are dominant with Liliaceae plants in the communities signiifcantly decreasing along the latitudinal gradient from south to north. The Shannon-Wiener index and biomass of communities all decreased along the latitudinal gradient with signiifcant negative linear regressions. The SDR2 (summed dominance ratio based on two factors) of dominant plants in the upper layers of communities, such as Stipa and Leymus chinensis, decreased along the latitudinal gradient from south to north. Especially, the SDR2 of L. chinensis decreased signiifcantly. The SDR2 of Cleistogenes squarrosa, Agropyron cristatum in the lower layers of communities and the indicator species for degradation were not affected. Potentilla acaulis was found mainly in the southern and northern areas. Stellera chamaejasme was found just in a few sites in the southern area of the EEST. In communities of Stipa grandis and Stipa krylovii, annual and biennial species are dominant. The ratio of annual and biennial species in the community is signiifcantly related to the latitudinal gradient. Perennial herbaceous plants and shrubs were not affected. According to the principal component analysis (PCA), with the data from 58×140 dimensions, the ifrst and second components had the lowest proportion, thus indicating that the species compositions and community structures are homogeneous along the EEST. There is a certain degree of spatial differentiation along the EEST due to degradation’s differences resulting from the different land uses.
其他文献
Based on the spatial conformations of human interleukin-6 (hIL-6) derived from nuclear magnetic resonance analysis and human interleukin-6 receptor (hIL-6R) mod
农村人口文化大院集娱乐、健身、学习、民主管理于一体。通过开展活动,成为党在农村发展社会主义先进文化,建设社会主义精神文明的阵地,要充分认识人口文化大院建设的重要意
The recombinant clones of pTN and pNT have been constructed by exchanging the coding regions of the movement proteins (MP), coat proteins (CP) and 3′noncoding
The effects of different concentrations of oxytetracycline (OTC) on the dynamics of bacterial and archaeal communities during the mesophilic anaerobic digestion
In this study the three-dimensional (3-D) model of the ligand-binding domain (V106-P322) of human interleukin-6 receptor (hIL-6 R) was constructed by computer-g
本文对夏热冬冷地区的绿色建筑相关技术和配套法规进行了介绍,主要以安徽省绿色建筑的发展为例,从绿色建筑技术的应用入手,结合安徽省的绿色建筑政策,指出夏热冬冷地区绿色建筑技
Grazing can dramatically affect arid grassland communities that are very vulnerable to environmental changes due to its relatively short and sparse ground cover
Wheat(Triticum aestivum L.) often experiences photoinhibition due to strong light during the grain filling stage. As such, increasing the tolerance of wheat to
通常情况下,混凝土结构设计师在设计建筑物的结构时,需要计算内力和分析结构,除了考虑建筑物结构的各个构件的使用功能之外,还需要遵照规定的安全度来测算各个构件的耐久性和承载
本文介绍了绿色建筑的定义和太阳能技术措施,发展绿色建筑,实现“人,自然,建筑”的相互和谐,我国绿色建筑持续发展战略,势在必行。