Effects Of Micro-topography On Vegetation Restoration In Different Types Of The Loess Plateau

The Loess Plateau is characterized by broken terrain.There are various types of microtopography such as scarp,platform,ephemeral gully,permanent gully and landslide on inter-valley area of the hilly Loess Plateau.Differences of site condition for plants caused by microtopography changes are often ignored when artificial afforestation is carried out on the Loess Plateau,resulting low survival and preservation rate of plantation.This study aimed to investigate the distribution of different types of microtopography and its influence on vegetation growth and restoration.24 typical small watersheds with returning farmland to forest(grass)since year 2000 in six subsections of the Loess Plateau were selected as study areas and microtopography,vegetation coverage and land uses were derived with GIS based on the high resolution remote sensing images.The main results are as follows:(1)The landscape fragmentation of inter-valley area on the hilly and gully loess region(type ?,type?,type ?,type IV and type V)and the plateau and gully loess region(type P)decreased in following order:type I>type ?>type P>type ?>type V>type ?.Permanent gully occupied the largest proportion in most subsections,and ephemeral gully had large plaque density but small area proportion.The proportion of scarp and platform are both small.(2)The mean vegetation coverage of scarp and most microtopographies of type IV and type V was significant smaller than undisturbed slope.Vegetation coverage difference between microtopographies of other region and undisturbed slope were quite small.(3)In type I,undisturbed slope was mainly herb structure.ephemeral gully was similar to undisturbed slope,a few shrub was found in scarp,platform,permanent gully and landslide while a few arbor distributed in platform and permanent gully.In type II.undisturbed slope was dominated by shrub-herb structure,ephemeral gully was similar to undisturbed slope,there were shrubs and arbors found in platform,permanent gully and landslide.In type ?.undisturbed slope and microtopography were both mainly herb structure.In type V,undisturbed slope was dominated by herb structure and a few shrub and arbor was found in platform,ephemeral gully,permanent gully and landslide.Microtopography had significant influence.In type III and type P,undisturbed slope of were dominated by arbor-shrub-herb structure,and the vegetation pattern of microtopography was similar to undisturbed slope(4)Take type ? for example to investigate the effect of microtopography on vegetation restoration under enclosed and artificial afforestation conditions.From 2007-2013,the growth of vegetation coverage was most improved in permanent gully and landslide in enclosed basin(Hegou),and in afforestation basin(Chaigou)it was landslide.In enclosed basin,growth of arbor proportion of permanent gully and landslide was larger than undisturbed slope.In artificial afforestation basin growth of shrub proportion of ephemeral gully and permanent gully was larger than undisturbed slope and growth of arbor proportion of landslide was larger than undisturbed slope.The result can provide basis for ecological restoration and artificial afforestation in the Loess plateau.