Abstract: With the reclaimed tidal wetland of Chongming Dongtan in Shanghai as a case, and based on the landscape pattern analysis of colored infrared aerial ph otographs and field survey, this paper studied the invasion of xerarch halophyte s and its effects on the original reed community in the wetland after artificial drainage. The results showed that in the test reclaimed tidal wetland area, the xerarch halophyte community with Tripolium vulgare as edificator was spreading from northeast to southwest at a high speed of 143 m per year, with the original reed patch reduced and broken sharply, causing a 227 times increase in patch d ensity index and a 13 times increase in shape index. After the growth seasons in 2006 and 2007, the biomass of T. vulgare in the plant community reached a s high as 27838 g·m-2，occupying 98% of the total, and the importance v alue reached 88%. At the mean time, the biomass and importance value of original reed decreased 98% and 83%, respectively. The invasion process of xerarch haloph ytes was meaningfully correlated with the moisture content and salinity in 0-20 cm soil layer. To effectively control the rapid invasion of xerarch halophytes, the mechanisms of their invasion and the strategies of ra tional and dynamic drainage management should be deeply studied.

Key words: urban functional area, soil, heavy metal, Shenzhen, ecological risk