榆林市土地利用变化对景观格局脆弱性的影响

Effects of Land Use Change on the Vulnerability of Landscape Pattern in Yulin City,Shaanxi Province

研究土地利用变化对景观格局脆弱性的影响,有助于了解区域生态环境的状况和变化趋势,为优化土地利用结构,科学制定土地利用规划,降低生态风险提供科学依据。本研究以榆林市土地利用数据为基础,从景观适应度和敏感度2个维度构建景观格局脆弱度,获取了景观脆弱度的空间分布及变化,并探讨了土地利用程度、动态度及转移类型对景观脆弱度的影响。结果表明:近25年,榆林市未利用地、水体、耕地减少,建设用地、林地、草地增加。不同景观类型相互融合,景观优势度降低,破碎化、均匀化、多样化趋势明显。景观格局脆弱性空间差异较大,北部风沙草滩区脆弱度高且上升明显,中、西部脆弱度低且有下降趋势,东部和东南部以中等脆弱区为主,变化不大。土地利用类型的空间分布、利用程度、变化速度、转化类型等与景观格局脆弱性密切相关,土地利用变化的结果使区域景观格局更为脆弱。加强耕地保护,控制建设用地过度扩张,防止林地碎片化是降低生态脆弱性的关键。

Research on the impact of land use change on the vulnerability of landscape pattern in Yulin city was helpful to understand the status and change trend of regional ecological environment and to provide scientific basis for optimizing land use structure,scientifically formulating land use planning,and reducing ecological risk.Based on land use data of Yulin city,this study constructed landscape pattern vulnerability from two dimensions of landscape adaptability and sensitivity,obtained the spatial distribution and change of landscape,and explored the effects of the land use degree composite index,the integrated land use dynamic degree and conversion types on landscape vulnerability.The results showed that over the past 25 years,,the unused land,waterbody and arable land decreased,while construction land,woodland and grassland increased.Different landscape types merged with each other,landscape dominance decreased,and fragmentation,uniformization,and diversity of the landscape pattern displayed an increasing trend.The spatial difference of landscape pattern vulnerability was quite large.The northern sandy beach area had a high degree of vulnerability which was in an obvious increase,while the central and western areas had a low degree of vulnerability which was in a downward trend.Besides,the eastern and southeastern areas were mainly medium vulnerable areas with little change.The spatial distribution,utilization degree,change speed and transformation type of land use were closely related to the landscape pattern vulnerability and the result of land use change made regional landscape pattern more fragile.Therefore,the key to reduce ecological vulnerability was to strengthen the protection of cultivated land,control the excessive expansion of construction land and prevent the fragmentation of forest land.