秦岭地区林地与草地景观格局变化及其驱动因素

以1980—2015年土地利用数据集为数据源,利用GIS空间分析、景观格局指数和主成分分析法,研究了秦岭地区林地与草地景观格局时空变化特征,并探讨其演化的驱动因素。结果表明:(1)林地和草地是秦岭地区主要景观类型,约占研究区总面积的72%,其中有林地为优势景观类型,其次为高覆盖度草地和中覆盖度草地,其他林地和低覆盖度草地分布面积相对较少。(2)35年来,林地和草地总面积整体呈减少趋势,净减少了309.44km~2,其中草地减少占主导地位;空间变化上,损失严重的区域主要分布于以西安市为中心的周边区域,主要向建设用地和耕地转移。(3)林地和草地景观破碎化程度逐渐增加,连通性降低,景观异质性增强且景观形状更为复杂,草地较林地变化明显;空间分布上,林地和草地景观格局指数空间分布特征明显,在地形因子作用下呈现一定的地形梯度性,尤其与海拔的相关性最好。(4)人为活动干扰是影响秦岭地区林地和草地景观格局变化的主要驱动因素,气候因素次之,同时国家宏观政策起着重要的导向作用。减缓人为活动对秦岭地区的过度影响,维护林地和草地的平衡性及完整性,是实现该区生态系统科学管理和资源的可持续利用的关键。

Landscape pattern changes of woodland and grassland and its driving forces in Qinling Mountains

Based on the land-use datasets from 1980 to 2015, in this study, we analyzed the spatial and temporal changes and its driving forces of woodland and grassland landscape pattern in Qinling Mountains following GIS, landscape pattern index, and principal component analysis methods. The results showed that:(1) Woodland and grassland were the main landscape types in the Qinling Mountains, accounting for about 72% of the total area of the study area. Among them, forest land was the dominant landscape type, followed by high-coverage grassland and moderate-coverage grassland, and other woodland and low-coverage grassland areas were relatively few. (2) The total woodland and grassland area of Qinling Mountains during 1980-2015 was decreased by 309.44 km². The grassland is dominated by the total area of woodland and grassland changes. Look at it from the aspect of spatial change, The woodland and grassland areas were mainly lost in the surrounding areas centered of Xi''an, woodland and grassland were mainly transformed to construction land and cultivated land. (3) The degree of fragmentation of woodland and grassland increased gradually, the landscape connectivity decreased, the landscape heterogeneity increased, and the landscape shape was more complicated. The grassland changed significantly compared with the woodland. Look at it from the aspect of spatial distribution, the spatial heterogeneity of woodland and grassland landscape pattern index was significant. and the national macro policy played an important guiding role in the change of landscape pattern. (4) Human activity interference was the main driving factors for the landscape pattern change of woodland and grassland in Qinling Mountains, followed by climatic factors. The national macro policy played an important guiding role in the change of landscape pattern. Mitigating the excessive impact of human activity on the Qinling Mountains and maintaining the balance and integrity of woodland and grassland are the key to realizing the scientific management of the ecosystem and the sustainable use of resources in Qinling Mountains.