Inland ports, being an immigration area and a potential spreading center, play an important role for investigating biological invasions. The Braunschweig inland port, during an investigation period of 30 years, shows 320 taxa growing on an area of about 22 ha. 48,44% of these species are indigenous, 23.75% are archaeophytes, 27.82% are neophytes. In 2002 only 235 of the whole number of species have been recorded. The differences between the floras of different inland ports as well as the species turnover is first of all due to unsteady neophytes, whereas the archaeophytes are relatively constant.