广西岩溶石漠化演变趋势及影响因素分析

Analysis on evolution trend and influence factors of rocky desertification in Guangxi

广西壮族自治区是我国岩溶石漠化较为严重的省区之一,监测其石漠化发展演变趋势与开展治理工作是一项长期任务。根据全国生态环境遥感调查与监测项目完成的石漠化遥感调查结果,分析了广西境内1999—2008年间石漠化的分布和演化情况,探讨了石漠化变化与整治措施及社会经济发展的关联性。研究结果表明,截至2008年,广西石漠化面积达1.703万km^2,约占全区总面积的7%,占碳酸盐岩分布区总面积的20.85%;其中,轻度、中度和重度石漠化面积分别占石漠化总面积的58.70%、29.02%和12.28%,以轻度和中度石漠化为主。9年间,全区石漠化总面积减少了1.026万km^2,年均减少面积0.114万km^2,年均增长率为-5.10%,石漠化总体面积减少,程度减轻,呈明显好转态势。石漠化的演变趋势与近年来一系列环境保护政策的落实、产业经济结构的变化、农民人均收入的增长等密切相关,如退耕还林措施、农业人口转移、农户家庭收入构成变化及沼气灶推广等均在减缓石漠化发展中取得了很好效果。然而,由于受地质背景、自然环境和人口因素的制约,广西石漠化治理的难点依然存在,任务仍很艰巨。

Guangxi Zhuang Autonomous Region is one of the more serious provinces of rocky desertification in Chi-na,and monitoring rocky desertification development and governing the environment is a long -term task.In this paper,the distribution and evolution of rocky desertification spanning nearly 10 years from 1999 to 2008 in Guangxi were analyzed by using the results of the national eco -environmental remote sensing survey and monitoring pro-jects,and the relevance between rocky desertification change and improvement measures as well as socio -economic development were discussed.The results show that,the area of rocky desertification in Guangxi is 1.703 ×10^4 km^2 by the end of 2008,which covers 7% of the total region and 20.85% of the area of the carbonate rocks.And the low,moderate and severe extent of rocky desertification areas are accounted for 58.70% ,29.02% and 12.28% of the total desertification area respectively.The low and moderate extent of rocky desertification are the dominant. The decreased area of rocky desertification was decreasing 1.026 ×10^4 km^2 during nine years,with average annual reduction of 0.114 ×10^4 km^2 and average annual growth rate of negative 5.10%.The general trend of desertification is good,which the overall area of rocky desertification is reduced,and the extent is relieved.The transformation trend of the rocky desertification is closely related to the implementation of environmental protection policies,the changes of the industrial economic structure and the growth of the average income.And the measures,such as retur-ning farmland to forests,agricultural population transfer,variation of peasant household income as well as promotion of household gas stoves,have achieved good results in slow down the development of rock desertification .However, there are serious difficulties in governing the rocky desertification in Guangxi caused by the restrict of geological background,natural environment and population factors.So these tasks above are very arduous for a long time.