Can the stepping stone enhance the establishment, competition and distribution of sown grassland species during recovery on exarable lands?

19 páginas, 8 figuras, 2 tablasMost diversity restoration projects are not to improve diversity per se , but rather to enhance the presence and abundance of species that are characteristic of reference or target community. The use of Bromus inermis suppresses annual noxious grasses and increases the control of other-forb group although these species are also noxious weeds; these may be substituted with another perennial species of the same functional group all through the whole experimental period, as it occurs with other perennialforb Carduus tenuifolius . A field experiment was conducted on abandoned arable land with sown low and high diversity treatments and natural colonization following typical farming practice for the site. Experimental plots were installed on former agricultural land that had been cropped with (a rotation of) monocultures until the end of 1995. The experiment was organized according to a block design with five replicate blocks. An opposite trend was performed among the colonizer species, because the colonizer grasses were relegated by the high dominance of sown grasses. But at the same time, the sown grasses facilitated the dominance of other colonizer-forbs species; therefore its functional replacement in the community due to sown effect was again tested. However, in natural conditions the other-forbs group was the dominant group, without taking into account the stepping-stone treatment and there was also a functional change of dominance. Our study has demonstrated the restoration effectiveness of species richness at abandoned arable land and may be enhanced by sowing late successional species.The experimental work described was supported by the Framework IV Environment and Climate Programme of the European Commission, contract number ENV4-CT95- 0002.Peer reviewe