东江流域集水区城市化差异及其对景观格局的影响

Differences in urbanization process of catchments in Dongjiang watershed and their effects on landscape pattern

基于东江流域1991、1998、2006年TM影像,通过分别代表东江流域上游、中游和下游的3个集水区各地物类型面积和景观指数分析了东江流域城市化程度与进程的差异及其对集水区景观格局的影响.结果表明:东江流域从上游到下游的城市化程度和进程依次增加;城市化对水体和植被的影响较大,城镇用地面积与水体面积呈显著正相关,城镇用地面积总体上与森林面积呈显著负相关,但当城市化发展到相对较高水平时可能促进森林恢复;1991—2006年间,上游的a集水区、中游的b集水区的景观格局均呈复杂化趋势;1991—1998年间,下游的c集水区景观格局呈复杂化,而1998—2006年间,则趋于简单,表明随着城市化的进行,景观格局呈"简单-复杂-简单"的变化趋势.研究东江流域景观格局从上游到下游的规律性变化对于整个流域的协调管理与可持续发展具有一定的指导意义.

Based on 1991, 1998, and 2006 TM images, the areas of different land use types and the landscape indices of three catchments （catchment a, b, and c, which represented upper, middle, and lower reaches, respectively） in Dongjiang watershed were analyzed, aimed to study the differences in urbanization process along Dongjiang River, and their effects on landscape pattern. The results showed that the degree and speed of urbanization increased from the upper to the lower reach of Dongjiang River. Urbanization had significantly effects on water and vegetation. Urban land area was positively correlated with water body area, and negatively correlated with forest land area. However, to some extent, urbanization stepped into a relatively high degree might benefit forest recovery. The landscape pattern of catchments a and b kept complicating from 1991 to 2006, while that of catchment c was getting complex from 1991 to 1998 and then becoming simple from 1998 to 2006, indicating that with the development of urbanization, landscape pattern presented a ＂simple-complex-simple＂ tendency. Understanding the change patterns of the landscape pattern along Dongjiang River would benefit the management and sustainable development of the watershed as a whole.