The spontaneous flora of urban streets of Braunschweig: High phytodiversity and unexpected dynamics of flora in a local scale

Roadsides are an important urban habitat, which till now is only rarely considered and only randomly investigated. Using the example of the city Braunschweig a complete investigation of the roadside flora was carried out. Within 15 year the plants growing spontaneously on public roads and places were registered. One important result is that the high biodiversity of cities is based not only on fallow land, railway sides as well as rests of near-natural habitats but also on road sides. In a whole 512 species have been found on road sides: 235 indigenous species (45.9 %), 164 neophytes (32 %), and 113 archaeophytes (22.1 %). The importance of non-resident plants as part of the city flora is documented by the high number of adventive plants 41.6 % of the recent flora of Braunschweig are the road side flora. This documents its importance for the conservation and the development of the biodiversity of cities. Also the high number of running wild ornamental plants and useful plants (174 species) is remarkable. The plants growing on various microhabits like pavement, tree-grids, traffic islands or embankments of motorways have been registered. On comparable roads, the plant life stock depends on length of the roads and the observation period. The high biodiversity of the road sides is very interesting. May be it is intensified by mechanical weed control