【作者】 皇甫江云；

【导师】 卢欣石；

【作者基本信息】 北京林业大学 ， 草业科学， 2014， 博士

【摘要】 我国西南岩溶地区的石漠化是喀斯特生态系统退化到极端的表现形式,严重制约区域社会经济的健康发展,已引起国内外广泛关注。草地是自然生态系统的重要组成部分。西南地区草地资源是原生植被森林破坏后,形成次生的草丛和灌草丛,具有明显的岩溶特征,是石漠化的重要组成类型。本研究采用坡度、岩石裸露率、草地植被盖度、草地类别和地上生物量为评价指标,通过层次分析法确定各指标权重,以草地石漠化指数(GRDI)定量评价草地石漠化程度,建立西南岩溶地区草地石漠化评价指标体系。将其划分为：无草地石漠化、潜在草地石漠化、轻度草地石漠化、中度草地石漠化和重度草地石漠化。以贵州省晴隆县作为案例,进行了草地石漠化系统研究：对晴隆县草地石漠化植被系统特征和群落排序进行研究,结果表明,随着草地石漠化程度的加剧,天然草丛、天然灌草丛的群落结构和多样性逐渐丧失,草层高度、草地植被盖度、地上生物量等,都呈现不同程度的递减趋势。通过地面监测和遥感影像结合的方法,获取研究区的坡度图、岩石裸露率图、草地类别图、草地植被盖度图和地上生物量图,进行栅格数据的空间叠加,获取1988年、1998年和2010年草地石漠化现状图。1988年～2010年草地石漠化动态监测结果为,轻度、中度、重度草地石漠化面积不断增加、程度不断加剧,草地石漠化状况依然严峻。1988年～1998年、1998年～2010年草地石漠化程度的空间变化特点以程度稳定型为主、程度退化型大于程度改善型的趋势。程度改善型以轻微改善型为主,程度退化型以退化加剧型为主。采用马尔科夫模型预测到2050年晴隆县不同程度草地石漠化的发展趋势。结果为无、潜在、轻度、中度草地石漠化面积逐年降低,而重度草地石漠化变化不大。随着时间的推移,不同程度草地石漠化得到逐步改善。采用岩性、地貌类型、海拔高度、多年平均降雨量、最大日降雨量、植被指数、人口密度、土地垦殖率、旱地面积比重和畜牧业产值占农业总产值比重10个指标,构建晴隆县草地石漠化驱动力评价指标体系。采用空间主成分分析方法,提取出草地石漠化的主要驱动力为人为因素(土地垦殖率、畜牧业产值占农业总产值比重)、岩性、年平均降雨量、海拔高程和地貌。根据空间主成分分析的结果,将草地石漠化脆弱性划分为5级：微度脆弱、轻度脆弱、中度脆弱、重度脆弱和极度脆弱,并对晴隆县各乡镇草地石漠化脆弱度进行分区评价。更多还原

【Abstract】 Rocky desertification of karst area in the southwest of China are the extreme form of degradation of karst ecosystems, which has severely hampered the healthy social and economic development in those regions, and has attracted wide attention domestic and overseas. Grassland is an important part of the natural ecosystem. With a significant karst features grassland resources mainly composed of the secondary growth of natural grass and shrub after the destruction of native forest vegetation in the southwest regions, also as an important class of Rocky desertification of karst area.In this study, evaluation index system of rocky desertification of grassland in the southwest karst area was established using slope, rock exposure rate, grassland vegetation cover rate, grassland vegetation types and biomass aboveground. Weighting of each index was confirmed using analysis hierarchy process and the extent of rocky desertification of grassland was quantitatively estimated according to the rocky Index. The extent of rocky desertification of grassland was divided into five scales, including none, potential, mild, moderate and severe.In case of Qinglong County, Southwest of Guizhou Province, rocky desertification of grassland was systematically researched.Research on vegetation characters and community sorting in rocky desertification of grassland area proved that with more and more serious rocky desertification of grassland, community structure and plant bio-diversities decreased, grass height, grassland vegetation cover rate and biomass aboveground did so to different extent. Slop image, bare rock ratio diagram, grassland type diagram, grassland vegetation coverage map, distribution map of biomass on the ground in the research area were obtained by remote sensing. Current distribution map in the years of1988,1998and2010were obtained by spatial overlaying the raster data.Dynamic monitoring on rocky desertification of grassland showed that area and degree of mild, moderate and severe type were increasing, with a serious situation of rocky desertification of grassland.Space transformation of different scales of rocky desertification of grassland from1988to1998and that from1998to2010was characterized by the trend of main stable degree of desertification, and greater degraded degree than improved degree. However, only a slight improvement but a serious deterioration was found predominantly in above degrees of rocky desertification.Rocky desertification of grassland from different degrees in2050was simulated with Markov process simulation. Results showed that the area of none, potential, mild and moderate degree of rocky desertification of grassland would decline year by year. While, that of sever degree of rocky desertification of grassland would remain unchanged. The total situation of rocky desertification of grassland would be improved.Constructing evaluation index system on driving force in rocky desertification of grassland was also performed based on ten index of lithology, geomorphology, altitude, annual average rainfall, maximum daily rainfall, vegetation index, population density, land reclamation rate, the proportion of dry land are, and the proportion of animal husbandry output value in the total output value of agriculture. And the main force included human factor including land reclamation rate and the proportion of animal husbandry output value in the total output value of agriculture, lithology, annual average rainfall and altitude.According to the spatial principal component analysis results, the grassland rocky desertification vulnerability is divided into5levels:Micro fragile, vulnerable, fragile, mild moderate and severe vulnerable, and the township of Qinglong County, grassland desertification vulnerability zoning evaluation.更多还原