INTRODUCTION

With the expansion of global trade and international transport and tourism after China's integration into the world economy through the implementation of its open-door policy in the 1980s and the more recent accession to the World Trade Organization (WTO), China's biodiversity is becoming more and more threatened by the potential introduction of nonnative species. According to the very latest statistics from the Ministry of Agriculture, more than four hundred alien species have invaded China, at least twenty in the last ten years. Alien invasive species are found in all of the thirty-four provinces, autonomous regions, and municipalities under direct control of the central government. By May 2002, they had invaded almost all of the fifteen hundred nature reserves nationwide and all types of ecosystems, including forests, farmlands, inland waters, wetlands, grasslands, and urban residential areas. More than half of the world's worst alien invasive species published by the IUCN have invaded China.

The international community has become aware of the serious threat of alien invasive species to the ecosystem, biodiversity, human health, and socioeconomic well-being. Studies have found that the introduction of nonindigenous species is second only to direct habitat destruction in causing loss of biodiversity.