The Past 30 Years, Northern Guangdong, Land Rocky Desertification Dynamic Changes And Development Trends

Rocky desertification, which creates great harm to the eco-environment, societyand economy development, is an important type of desertification in south China. Sothe rocky desertification has been a popular reach question. The karst mountainousarea of northern Guangdong is a typical region of rocky desertification lands. Thereach of its'change rule and developmental tendency has an important theory andactual significance.The article firstly had a summary of former reach in rocky desertification, 3stechnology's development and interpreting theory of remote image, then based onthe theory of theoretical datum plane of rocky degradation, under the principle ofintegration, dominant and maneuverability, selected four indexes which includingrock, vegetation, soil and the types of lands use, then established the four classifyingtypes and synthetically landscape of rocky desertification lands. Secondly throughon-the-spot investigation in GPS technology, established the relationship ofgeographic space and image space and then determined remote sensing interpretationkeys of the rocky desertification lands. Lastly the article finished interpreting theremote images by eyes in Arcview3.3, which included land multispectral scannerimage acquired in 1974 and landsat thematic image acquired in 1988 and 2004 ofYangshan, Lanzhou, Yingde, Ruyuan cities in northern Guangdong. Through theformer work, it lastly obtained a series of maps, including the map of spatial andtemporal changes in rocky desertification and land use of four counties in karstmountainous area of northern Guangdong in recent 30 years and lands change mapsof rocky desertification in the two times of from 1974 to 1988 and from 1988 to2004. They reflected the change scene of rocky desertification land in northernGuangdong in recent 30 years.Through GIS spatial analysis, the article also obtainedthe intersection dates between 1974 and 1988 and between 1988 and 2004, throughwhich can obtain the land interchange in 30 years. Using some models, such as thedegree of dynamism, calculating analysis model, transfer probability matrix, relativevariation and et al, the article discussed the dynamic changes of rocky desertificationlands. Finally the analysis suggested: (1) the area of rocky desertification lands wasgradually reducing, and the speed of reversal during the time from1988 to 2004 wasmuch faster than from1974 to 1988; (2)the progress of development and reversion inrocky desertification principally consisted of the transferring between woodland anddesertification land. Transferring among desertification lands was occurred in thedirection of reduced degree; (3) the law of spatial variation is that the rocky desertification reversed in all research region, but in middle-east of Yangshan andwest-north of Ruyuan there are rocky desertification lands in laminated shape and inthe other region the rocky desertification lands reversed in the direction of littledistribution, shorten shape and reduced degree. At last the article forecasted thetendency of rocky desertification lands change in the future 32 years throughMarkov model, power model and synthetical growth model. The area of rockydesertification lands will be largely shorten in the high speed in the fhture, whichwill be shorted to 418.76 Km~2 in 2020 and 342.41 Km~2 in 2036.