Dynamics of the main landscape types at Shenzhen bay during past three decades

Shenzhen Special Economic Zone (SEZ) was established as a model city in 1979 and it has become a modern industrialization urban during the past three decades. The rapid urbanization has a significant effect on the landscape, and Shenzhen Bay is a typical example. In this paper, the urbanization process in Shenzhen special zone was divided into four stages: early urbanization phase, developed urbanization phase, accelerated urbanization phase and later urbanization phase. Based on five periods of remote sensing data located at Shenzhen Bay, including MSS in 1979, and TM in 1989, 1998, 2003, 2009, respectively the dynamic characteristic of three main wetland landscape types, Gei Wei, Mangrove and Intertidal Zone in Shenzhen Bay, was analyzed with a series of techniques including landscape classification, landscape transfer and landscape index analysis. The software platforms including ERDAS IMAGINR, ARCGIS and FRAGSTATS. The results are as followed: (1) There are higher diversity landscape types at Shenzhen Bay, while the area of different landscape type varied greatly. Human disturbance is a major factor in the change of landscape pattern of Shenzhen Bay, the reclamation work projects and urban construction had seriously destroyed the coastal wetlands, the coastline of the Shenzhen Bay also had extended to the shallow water. (2) During the past three decades, the built-up area increased from 508.95 hm ² to 2 072.52 hm ², accordingly the largest patch area index increased from 2.94% to 17.55%. (3) Gei Wei suffered the greatest human disturbance, its cover area increased in the early urbanization phase. Its proportion was 7.72% in 1989, the highest value during the past three decades. With the acceleration of urbanization, Gei Wei gradually evolved into built-up areas or other landscape types with the patch shape turn regular. In the last two phases, Gei Wei maintained at a low level of the move in or out and mainly occurred in Nanshan District where several large-scale reclamation work projects proceeded. (4) The total mangrove area decreased constantly in the first two phases of urbanization, but began to increase after 1998, with 52.65 hm ² of area to 81 hm ² in 2009. Landscape index analysis showed that the mangrove landscape did not become fragmented, but shaped larger landscape patches and the landscape connectivity increased. (5) There was a relatively large fluctuation and iterancy for intertidal zone in the past three decades, with the area reduced from 634.5 hm ² in 1979 to 377.28 hm ² in 2009, and the fragmentation increased with the stability declined.