渝西农业区土地利用动态与景观格局分析——以铜梁区张家沟小流域为例

Dynamics of Land Utilization and Landscape Pattern Analysis in Agricultural Region of Chongqing West:a Case Study of Zhangjiagou Catchment in Tongliang District

以铜梁区张家沟小流域为例,基于1957—2014年5期矢量数据,分别运用景观格局指数、景观扩张指数以及土地利用动态度等方法,研究渝西农业区土地利用及景观格局时空变化规律。结果表明,张家沟小流域土地利用综合动态度在1998—2014年间最高(9.25%),1983—1998年间最低(7.74%),且年变化速率较高,发展较快;研究时段内张家沟小流域斑块数目不断增加,旱地面积大幅下降,林地覆被面积先减少而后逐步恢复,居民点斑块规模小、数目多、形状复杂、分布零散破碎;小流域总体以水田为优势景观,且水田面积不断扩大,至2014年水田面积已达7.28km2,占小流域总面积的49%,扩张模式多为邻接式小规模扩张。研究认为,作为渝西较典型的农业片区,1957—2014年间张家沟小流域土地利用及景观格局变化逐渐趋于稳定,景观斑块数目未来依然有不断增加的趋势,随着重庆市经济的不断发展以及相关政策规划的实施,未来该农业片区土地利用年变化速率依然可能偏高。

Land use and landscape patterns of spatiotemporal variation rules in Zhangjiagou catchment in Tongliang district of the west of Chongqing are studied by five vector data during the periods from 1957 to 2014, By using the theory of landscape ecology of landscape pattern index, landscape expansion index and comprehensive dynamic degree of land use and other methods respectively, The results showed that： 1） comprehensive dynamic degree of land use had a higher annual variation rate and a comparatively high pace development, with the highest value 9.25 % in 1998--2014 and the lowest value 7.74 ~//0 in 1983--1998; 2） During the research period, the patches number increased constantly, the dry land areas dropped sharply, and the cover areas of forest reduced initially and then increased gradually in the catchment, the residential patches had the features of small scale, large numbers, complex shape and scattered broken distribution; 3） Overall, paddy filed acted as its dominant landscape in this catchment and this paddy field area was expanded continuously,which had reached 7.28 km2 that accounted for 49% of the total area of this catchment until 2014. The expansion models, in generally, were adjacent small scale expansion; The research suggests that as the small typical agricultural ar- ea in the Western area of Chongqing, the changes of land use and landscape patterns have been into a stable condition gradually in Zhangjiagou catchment from 1957 to 2014. With the development of economy in Chongqing and the implementation of relevant plan- ning policies, the number of landscape patches still stay in an upward trend. The annual change rate of the land use in this agricul- tural area would be a little high in future.