长白山区生态用地破碎化演变及土地利用变化研究

随着城镇化进程的推进,土地资源破碎化现象逐步加深,严重威胁着区域生态安全、土地利用格局和人类生存环境。通过构建景观破碎度评价模型,研究了我国东北典型山区长白山区1995—2015年的生态用地破碎化程度及其动态变化特征。结果表明:①长白山区20年间生态用地破碎化程度降低,破碎化区域缩小,生态景观格局趋于安全。②各用地类型之间转换频繁,林地主要向草地转化。③20年来生态用地面积逐年缩小,内部类型变化幅度大于生态用地本身。④除了人类活动,城市扩张、耕地复垦等土地利用政策也是影响土地利用变化的外在因素。

Ecological Land Fragmentation Evaluation and Dynamic Changes in Changbai Mountain Areas

Mountainous area had typical ecological fragility,which was called high-energy environment area where even a small change would cause strong ecological chain reaction.Ecological land was a land use category provided with considerable ecological value and a vital indicator reflecting the regional eco-environment quality.With the processing of China′s urbanization,the fragmentation of land resources had gradually deepened,seriously threatening regional ecological security,land use patterns and human living environment.Therefore,analysis of spatiotemporal change of ecological land use and ecological landscape pattern in mountainous areas seemed necessary.In this paper,Changbai Mountain areas were selected as the study area.A landscape fragmentation evaluation model was used to measure the degree of fragmentation of regional ecological land,and determined land use change features through land-use transfer matrix during the period from 1995 to 2015.The results showed:①The degree of fragmentation of ecological land in Changbai Mountain areas has decreased during the past 20 years.②The conversion between ecological land and other land types was quite frequent.And forest land mainly transformed to grassland.③The ecological land use decreased year by year from 1995 to 2015,and the change range of the internal type was larger than that of the ecological land itself.④Besides human activities,land use policies such as urban expansion and cultivated land reclamation were also external factors affecting land use change.Strict restrictions on urban expansion were conducive to releasing excess ecological land and improving the pattern of ecological land use.