On the influence of horticulture on the flora of edges of forests

Edges of forests in the neighbourhood of settlements are in general characterized by a high degree of disturbance as well as by the occurrence of alien plants. 139 taxa of ornamental and useful plants were found on edges of forests in the neighbourhood of settlements in the eastern part of Lower Saxony. These are only 1,1% of all plants imported to Germany. Alien plants are running wild especially in the planar-colline belt wbereas the accumulation of alien plants is relatively the higbest on soils poor in nutrients. Many species are dependent on a permanent supply of diaspores and are therefore to be classified as ephemerophytes. Because of the lack of light only a few species as Lamiastrum galeobdolon ssp. argentatum; Ribes uva-crispa or Helleborus viridis are ahle to penetrate into the forests. Naturalizing of aliens as well as back-migration of garden plants coming from forests resp. edges of forests are discussed intensively. Species of the indigenious flora are indangered by aliens only in some special cases in the eastern of Lower Saxony, nevertheless long-tern observations and documentation of the species turnover of edges of forests are recommended