石漠化治理下土地利用与景观格局变化

Change of land use and landscape pattern under rocky desertification control

【目的】探讨石漠化综合治理下土地利用/覆被变化及其景观格局变化特征与规律,为生态修复和植被重建、农业产业结构调整提供科学依据。【方法】基于2009、2015和2019年3期的影像数据和GIS与RS技术,利用土地利用变化模型和景观格局指数,系统分析2009—2019年撒拉溪喀斯特高原石漠化治理区的土地利用变化及其景观格局。【结果】①研究期内示范区土地主要利用类型为耕地、有林地和灌木林地,耕地面积减少最大,达914.85 hm^(2),裸岩石栎地和裸土地等未利用地面积减少,灌木林地和草地面积增加,园地面积增加迅速且动态变化度最大,为184.77%;建设用地面积增长迅猛,从2009年的149.57 hm^(2)增加到2019年的381.89 hm^(2)。②撒拉溪示范区2009、2015和2019年土地利用程度综合指数分别为247.25、243.25和245.53,研究期内示范区土地利用程度呈下降趋势,但总体上变化不大;2009—2015年的土地利用程度变化率与综合土地利用动态度均大于2015—2019年。③2009—2015年示范区内土地利用斑块水平景观指数变化显著,2015—2019年间变化较缓。研究期内示范区景观多样性、均匀度上升,景观破碎化程度增高、蔓延度下降。【结论】人类活动对土地利用的干扰程度加大,石漠化综合治理、退耕还林还草工程和建设工程对景观格局的影响大于产业结构调整和退耕还果还园工程。

[Objective]The characteristics and laws of land use/cover change and landscape pattern change under the comprehensive management of rocky desertification(RD)are explored,so as to provide a scientific basis for ecological restoration,vegetation reconstruction and agricultural structure adjustment.[Method]Based on the image data of 2009,2015 and 2019 and GIS&RS technology,the model of land use change and landscape pattern index were used to systematically analyze the land use/cover change and landscape pattern of Salaxi RD control area in the karst plateau from 2009 to 2019.[Rusult](i)The main land use types in the demonstration area were cultivated land,woodland and shrub land.The area of cultivated land decreased most,which was 914.85 hm^(2).The area of unutilized land such as bare rock land and bare land decreased,the area of shrub land and grassland increased,and the garden area increased rapidly which had the largest dynamic change with 184.77%.The area of construction land has grown rapidly from 149.57 hm^(2) in 2009 to 381.89 hm^(2) in 2019.(ii)The comprehensive index of land use degree in the Salaxi Demonstration Area in 2009,2015 and 2019 were 247.25,243.25 and 245.53.During the study period,the degree of land use in the demonstration area showed a downward trend,but there was little change overall.The rate of land use change degree and comprehensive dynamics degree land use in 2009-2015 were all greater than that of 2015-2019.(iii)The landscape indexes at patch level of land use changed significantly between 2009 and 2015,and the change was slower between 2015 and 2019.The diversity and evenness of the landscape increased,the landscape fragmentation aggravated,and the contagion decreased during the study period.[Conclusion]The disturbance for land use has increased due to human activities,while the comprehensive control of RD,grain for green projects and construction projects have greater influence on the landscape pattern than the adjustment of industrial structure and the farmland returning to orchards.