Restoration of a Danish headwater stream: short-term changes in plant species abundance and composition

1. This paper describes the short-term effects (2 years) of stream restorat ion on vascular plant communities in a 1.4 km upper reach of the River Gude na, Denmark. The effects of restoration were assessed in terms of the abund ance and composition of plant species in the stream, on the banks and in th e stream valley. 2. Total species richness was similar before and after restoration, and com prised approximately 150 species representing 12% of the entire Danish vasc ular plant flora. 3. In the stream, total plant cover had not recovered to pre-restoration le vels 2 years after restoration. Cover by submerged, amphibious and terrestr ial species growing submerged decreased, as did the number of amphibious an d terrestrial species growing submerged. 4. On the banks, total plant cover almost attained pre-restoration levels t he second year after restoration. The plant communities changed from domina nce by non-riparian species to more diverse communities with a greater numb er and increased cover of riparian gramineous species requiring a higher so il moisture content. 5. In the valley, the plant communities only changed slightly after restora tion, although growth of riparian species was enhanced on the southern side of the stream. Copyright (C) 2000 John Wiley & Sons, Ltd.