基于3DLP指数的景观格局演变及预测分析

采用1987、1999、2009和2017年四期Landsat TM/OLI数据,结合GIS和RS技术,从类型和景观层面计算安化县四个年度的3DLP指数,分析安化县近30年来景观格局的动态演变并利用CA-Markov模型对2025年景观格局演变进行模拟和预测,为推动该县今后生态环境的进一步恢复和改善提供指导。结果表明:(1)林地是安化县的优势景观,对安化县景观的主控作用强。(2)从不同景观类型来看,1987—2017年期间安化县各景观破碎化情况均有所缓解,其中建设用地、林地面积增加,草地、水域、农地面积减少;林地、水域边界形状趋于简单化,建设用地、草地边界形状趋向复杂化,农地边界形状受人类活动影响较小。(3)从整体景观来看,安化县景观格局的演变主要是受到人为因素的影响,1999年整体边界形状变得更为规则,同时破碎化程度、景观异构性以及多样性有所提高。1999—2017年各类景观类型的面积比例差异增大,破碎化程度以及景观异质程度降低,优势景观类型份额增加。(4)根据预测结果来看,安化县整体趋向均衡化发展,边界形状趋向规则化,景观异质性程度降低,各类景观类型的面积比例差异减小,林地出现被其他景观蚕食分割的趋势,因此需要进一步提高对林地的重视和保护,限制其他景观类型对林地的干扰。

Analysis of landscape pattern evolution and prediction based on 3DLP metrics

Four phases of Landsat TM/OLI data of 1987,1999,2009 and 2017 are adopted to calculate the 3DLP metrics of Anhua County in these four years from the aspects of type and landscape with GIS and RS technologies.Dynamic evolution of the landscape pattern of Anhua County in the past 30 years is analyzed and the evolution of landscape pattern in 2025 is also simulated and predicted by CA-Markov model,which could provide guidance for future restoration and improvement of ecological environment.The results show that:(1)Forest is the advantageous landscape of Anhua County,which has powerful controlling effect on landscapes of Anhua.(2)Seen from different landscape types,during 1987 to 2017,landscape fragmentation was alleviated in Anhua,among which the areas of construction land and the forestland increased,while the areas of grassland,water and agricultural land decreased;the boundary shape of forestland and water area tended to be simplified,the boundary shape of the construction land and the grass land tended to be complicated,and the boundary shape of the agricultural land was affected little by human activities.(3)Seen from the overall landscape,the evolution of landscape patterns of Anhua County was affected mainly by human factors.In 1999,the overall boundary shape became more regular,and at the same time the fragmentation degree,the landscape heterogeneity and diversity were improved.From 1999 to 2017,the area proportions of various types of landscapes differed greatly,the degrees of landscape fragmentation and heterogeneity were lowered,and the proportion of advantageous landscapes was increased.(4)Seen from the prediction results,the general tendency of Anhua County developed in balance,and the boundary shapes tended to be regular,the degree of landscape heterogeneity was decreased,the area proportion of various landscapes was diminished,and the forest showed the tendency to be intersected by other landscapes.Therefore,it is necessary to improve concern on and protection of the forest and prevent the forest being affected by other landscapes.