陕北黄土区坡面微地形与群落数量特征的关系

The relationship between slope micro topography and community quantity characteristics in loess area of North Shaanxi province

为探究陕北黄土区坡面植物群落数量特征与微地形间的关系,以及构建半干旱黄土区稳定高效的林草植被模式,在陕北黄土区吴起县合沟流域,对流域内切沟、塌陷、缓台、浅沟和陡坎这5种坡面微地形植物群落的各项数量特征进行调查。发现:1)微地形与植物群落的数量特征间存在一定相关性。2)各类微地形以草本群落为主,其中半阴坡微地形植物群落的植物种数、盖度、生物量、多样性等特征值大多优于半阳坡,自然演替速率较快。3)各类坡面微地形植物群落的各项特征值多优于原状坡面,其中陡坎的植物群落生长状况最差,切沟最优。陕北黄土区各类坡面微地形与植物群落数量特征间具有一定的相关关系,在进行植被恢复时应针对不同微地形,考虑其植物群落结构与特征的差异,以恢复与保护草本群落为主,使陕北黄土区自然植被更稳定地演替。

[Background]The objective of this study is to grasp the relationship of plant community quantitative characteristics and various types of micro topography in the loess area of northern Shaanxi province,and this research has certain significance for the vegetation restoration and reconstruction on difficult sites in semi-arid loess area of northern Shaanxi province.[Methods]Based on the survey data of a series of plant community quantitative characteristics such as species composition,herbaceous biomass,vegetation coverage and vegetation diversity on 5 micro-topographies of Hegou valley in Wuqi county of northern Shaanxi province,including gully,collapse,platform,shallow gully,scarp and the undisturbed slope,the correlations between micro-topographies and plant community quantitative characteristics were analyzed.The data were processed via statistical analysis and significance test of difference.[Results]1)The slope micro-topography has a significant impact on vegetation growth.There is a significant correlation between the micro-topography and the plant community quantitative characteristics like richness,herbaceous biomass,vegetation coverage,vegetation diversity and other indexes.2)The plant communities on the various types of micro-topography are dominated by herbaceous communities.Among them,the plant community quantitative characteristics on different slope micro-topography of the semi-shady slopes are mostly superior to those on semi-sunny slopes,and the natural succession stage of the plant community is more advanced than semi-sunny slopes,too.3)The characteristic of the species composition,herbaceous biomass,vegetation coverage and vegetation diversity of plant communities in various types of slope micro-topography are better than those on the undisturbed slope.Among them,two types of shrubs appeared in the gully,and the vegetation growth in the gully was the best,followed by the vegetation growth in the collapse,platform and shallow gully is slightly worse,while the vegetation growth of the scarp was the worst.[Conclusions]There is a certain relationship between the vegetation characteristics and the micro-topographies in the loess area of northern Shaanxi province.Different micro-topographies in loess area of northern Shaanxi province has caused the spatial differences of habitat conditions,which resulted in the significant differences in vegetation characteristics.Therefore,when vegetation restoration is carrying out in the loess area of northern Shaanxi province,the differences of plant community characteristics should be considered based on the characteristics of different micro-topographies,aiming to promote the guide for the vegetation restoration on difficult position in the loess area of northern Shaanxi province.