广州市土地利用垂直分层模式及其演变过程

城市中不同高程上的土地受人类活动影响程度和影响方式不一,因此在垂直方向上形成了一定的分布模式。利用TM遥感影像数据和DEM数据,通过比较1990、1995、2000、2005和2009年广州市土地利用垂直分布特点发现,每个地类均有相对集中分布的高程级,而垂直分布的最大变化是居民点及工矿用地和园地在第3至第10高程级(1~90 m)之间对耕地和林地的快速侵占。总结各高程级上的优势地类可得出典型的广州市土地利用垂直分层模式,按照第一优势地类对各分层进行命名,结果显示随高程增大将依次出现耕地层、河流层、城镇层、园地层、林地层。最后应用生态学上的群落演替理论对城市土地利用垂直分层模式的演变过程进行解释,以及按照目前发展趋势推导出未来可能出现的演替模式。

Vertical Hierarchical Model of Urban Land Use and the Progress of Evolvement in Guangzhou

All land use types in the city are affected by human, but the impact on each type varied enormously, hence vertically forming a certain distribution model. In a flat country, distance is the most important factor that interferences the distribution of land use; and basing on this assumption, Von Thünen and Burgess introduced their famous concentric models. However, the absolute flat country is inexistent, so how does the elevation affect the distribution of urban land use? Would it establish its own unique land use model of distribution in vertical orientation? In this paper, a case study was conducted in Guangzhou City by comparing land use vertical distribution pattern in 1990, 1995, 2000, 2005 and 2009 using remote sensing image interpretation and DEM data. The results showed that: 1) Various types of land use showed different characteristics of distribution changing with elevation. Some types of land use are mainly concentrated in a range of elevation, while other types of land use are relatively scattered. 2) From low elevation to high, the most dominant types of land use vary from farmland, water, urban land, orchard, to woodland in 2009. With the raise of elevation, the advantage of the most dominant type decreases first and then increases quickly. 3)From 1990 to 2009, the overall trend of the magnitude of land use change in vertical orientation are similar: the intensity of land use change decreases with the raise of elevation; and in the progress of land use change, the primary changes of land use are the spread of urban land and orchard and the retreat of farmland and woodland between 1 m to 90 m. 4) Based on the definite landforms and stage of economic development, the corresponding vertical land use hierarchical models of land use will form. From low elevation to high, the vertical land use hierarchical model in Guangzhou is composed of the layers of vertical land use, i.e., mixed layer of farmland, fishpond and shoaly land; mixed layer of water and farmland; mixed layer of urban and farmland; mixed layer of orchard, farmland and agricultural settlements; mixed layer of orchard, woodland and farmland; mixed layer of orchard and woodland; and woodland layer. 5) We discussed the vertical hierarchical model of land use in natural landscape period, agriculture landscape period, rapid-urbanization period, post-urbanization period and complete-urbanization period. And the theory of succession of community in ecology can well explain the evolvement of vertical hierarchical model of urban land use.