【作者】 徐修桥；

【导师】 谢炳庚；

【作者基本信息】 湖南师范大学 ， 土地资源管理， 2020， 硕士

【摘要】 目前,石漠化危害及其治理成为我国喀斯特地区生态研究的热点和难点之一,只有对石漠化的演变特征和形成机理进行深入探究,才能更好地指导石漠化地区生态恢复。人类活动作为石漠化产生的重要因素之一,分析其变化特征与石漠化的相互关系,能够揭示石漠化产生的人为因素驱动机理,指导石漠化地区农村居民点布局优化和制定石漠化治理工作方案。本研究选取广西平果县为研究区域,作为广西乃至全国喀斯特面积最大、喀斯特地貌发育最典型、石漠化面积最广和最严重的地区之一,平果县也是贫困人口和少数民族聚集区,以及石漠化生态治理示范区,当地人口、经济、生态之间矛盾突出,在西南地区喀斯特研究中具有重要代表意义。本研究通过对1989-2017年间平果县农村居民点用地规模、斑块数量、密度、形态、变异系数和石漠化的规模、演变类型、变异系数和严重程度等指标的变化特征进行归纳描述,找出二者的时空演变规律;在此基础上构建地理探测器模型,将石漠化演变类型、变异系数、综合分值与农村居民点用地规模、斑块数量、变异系数、景观形状指数、演变速率进行相关分析,找出其内在的驱动机理和相互作用,得出结论如下:(1)平果县农村居民点用地受交通干线和河流影响,空间分布不均,整体呈现东北、西南多,中部少的特点;密度特征表现为南北密、中部疏,向城镇、河流、交通干线两侧集聚,且集聚趋势越来越显著,低密度区域变化缓慢,高密度区域密度持续增加,由“单点高值”向“多点高值”集中;景观形状指数南高北低、由西南向西北递减,在1989-2017年间,景观指数不断增长,斑块不规则程度增加,演变速率表现为慢-快-慢-快的态势。(2)平果县石漠化规模排序依次是:强度>潜在>中度>极强度>轻度,县域东北部、西南部等居民密集区石漠化较为严重,在1989-2017年间,平果县石漠化面积呈现增-减-增-减的波动变化趋势,无石漠化面积增加、中度和强度石漠化相对稳定、轻度和极强度石漠化在治理工程下显著减少,演变多发生于不同强度石漠化交界处;石漠化面积整体波动较小,大致呈现西南、中部波动减少,东南、北部波动增加的规律;石漠化演替类型以稳定型为主,正向演替与逆向演替基本持平,年际演替速率不均。(3)农村居民点演变速率、变异系数和景观形状指数和对石漠化演变具有较强的解释力和一定的协同力,对石漠化演变其重要作用;任意两个农村居民点用地驱动因素的交互作用对石漠化空间差异的影响均大于单一驱动因素,且交互作用类型均为双因子增强或非线性增强,农村居民点的演变速率、变异系数和景观形状指数对其它指标具有较强的协同加强作用;对石漠化演变起重要解释作用的指标均具有较好的显著性检验结果,进一步证实农村居民点演变速率、变异系数与景观形状指数是石漠化演变的主导因子,并对石漠化各指标的变化有重要的解释作用。(4)对农村居民点进行合理的规划和布局,可减少因农村居民点建设造成的人类不合理活动,能够有效减缓石漠化恶化进程;石漠化治理应根据其强度特征进行分区治理,因地制宜地安排生态搬迁、小流域治理、生态立体农业、生态旅游、封山育林、植被管护等治理措施;完善公共服务和基础设施建设,引导人口和农村居民点分布,改善农户生计方式,对于缓解石漠化地区人地矛盾具有重要辅助意义。更多还原

【Abstract】 At present,the harm of rocky desertification and its control has become one of the hotspots and difficulties in the ecological research of karst areas in China.Only by deeply exploring the evolution characteristics and formation mechanism of rocky desertification can we better guide the ecological restoration of rocky desertification areas.As one of the important factors of rocky desertification,human activities can reveal the driving mechanism of man-made factors by analyzing the relationship between its changing characteristics and rocky desertification.to guide the optimization of the layout of rural settlements in rocky desertification areas and the formulation of a work plan for the control of rocky desertification.In this study,Pingguo County in Guangxi is selected as the study area,as one of the areas with the largest karst area,the most typical karst geomorphology and the widest and most serious rocky desertification area in Guangxi and the whole country.Pingguo County is also a gathering area of poor population and ethnic minorities,as well as a demonstration area for ecological control of rocky desertification.The contradiction among local population,economy and ecology is prominent,which has important representative significance in karst research in southwest China.This study summarized and described the change characteristics of rural residential land scale,patch number,density,shape,coefficient of variation,scale,evolution type,coefficient of variation and severity of rocky desertification in Pingguo County from 1989 to 2017.to find out the law of their spatiotemporal evolution.On this basis,a geographic detector model is constructed to analyze the correlation between the evolution type,coefficient of variation,comprehensive score of rocky desertification and rural residential land scale,patch number,coefficient of variation,landscape shape index and evolution rate.the internal driving mechanism and interaction are found out,and the conclusions are as follows:(1)Affected by traffic trunk lines and rivers,the spatial distribution of rural residential land in Pingguo County is uneven,showing the characteristics of more in Northeast and Southwest and less in Central;and the density is dense in the north and south and sparse in the middle,gathering to both sides of towns,rivers and traffic trunks.and the trend of agglomeration is becoming more and more obvious,the change of lowdensity area is slow,and the density of high-density area increases continuously,from "single-point high value" to "multi-point high value";The landscape shape index is high in the south and low in the north,and decreases from southwest to northwest.During 1989-2017,the landscape index increases continuously,the patch irregularity increases,and the evolution rate shows a slow-fast-slow-fast trend.(2)The order of the scale of rocky desertification in Pingguo county is as follows: intensity > potential > moderate > extreme intensity > mild.Rocky desertification in densely populated areas such as northeast and southwest of the county is more serious.During 1989-2017,the area of rocky desertification in Pingguo county showed a fluctuating trend of increase-decrease-increase-decrease.The area without rocky desertification increased,moderate and intense rocky desertification was relatively stable,and mild and extreme intensity rocky desertification significantly decreased under the control project.The evolution mostly occurs at the junction of rocky desertification of different intensity.The overall fluctuation of rocky desertification area is relatively small,roughly showing the law of fluctuation decreasing in southwest and central part,and increasing in southeast and north;the succession type of rocky desertification is mainly stable,the forward succession and reverse succession are basically the same,and the interannual succession rate is uneven.(3)The evolution rate,coefficient of variation and landscape shape index of rural settlements have strong explanatory power and coordination to the evolution of rocky desertification,which play an important role in the evolution of rocky desertification.The influence of the interaction of any two driving factors of rural residential land on the spatial difference of rocky desertification is greater than that of single driving factor,and the type of interaction is two-factor enhancement or non-linear enhancement.The evolution rate,coefficient of variation and landscape shape index of rural settlements have a strong synergistic effect on other indicators.All the indexes that play an important role in explaining the evolution of rocky desertification have good significance test results,which further confirms that the evolution rate,coefficient of variation and landscape shape index of rural settlements are the leading factors of rocky desertification evolution.it also plays an important role in explaining the changes of each index of rocky desertification.(4)Rational planning and layout of rural residential areas can reduce the unreasonable human activities caused by the construction of rural residential areas and effectively slow down the deterioration process of rocky desertification,and rocky desertification control should be carried out according to its intensity characteristics.according to local conditions to arrange ecological relocation,small watershed management,ecological three-dimensional agriculture,eco-tourism,mountain closure for forest,vegetation management and other management measures;Improving public services and infrastructure construction,guiding the distribution of population and rural settlements,and improving the livelihood of farmers have important auxiliary significance for alleviating the contradiction between people and land in rocky desertification areas.更多还原