The Severn basin : sample basin review [Le bassin de la Severn ]

The Severn basin embraces a range of terrain types and it is particularly appropriate to study the basins. To progress further understanding of the Severn and Wye basins, four groups of specific research themes have been established.Le bassin de la Severn, qui traverse plusieurs types de terrain, peut servir de modèle pour l'étude des bassins fluviaux. Quatre thèmes de recherches ont été retenus afin de compléter les connaissances concernant le bassin de la Severn et celui de la Wye.Gregory K. J., Thornes J.B. The Severn basin : sample basin review [Le bassin de la Severn ]. In: Bulletin de l'Association française pour l'étude du quaternaire, vol. 17, n°1-2, 1980. pp. 61-64

Plant traits enabling survival in Mediterranean badlands in northeastern Spain suffering from soil erosion

8 páginas, 4 tablas.-- El PDF es la versión post-print.[Question]: This study analysed the effect of severe soil erosion on species composition of plant communities by favouring species showing certain growth forms, root-sprouting and clonal growth abilities. [Location]: The study area was located between the middle Ebro Valley and the Pre-Pyrenees (northeastern Spain). [Methods]: Root-sprouting and shoot-rooting abilities, clonal reproduction and growth form were assessed for the 123 most common plant species from eroded lands in the study area. We obtained 260 vegetation relevés in three different substrata (gypsum outcrops, Miocene clays and Eocene marls) on areas with different degrees of soil erosion. The frequency of every plant trait in each relevé was estimated according to species presence. The effect of soil erosion on the frequency of plant attributes was assessed by correlation analyses. [Results]: Bipolar, non-clonal plants and annual species decreased their frequency with increasing soil erosion in the three substrata analyzed, whereas root-sprouters and woody plants (mostly sub-shrubs) increased their frequency in most of the substrata analysed. [Conclusions]: Woody sub-shrubs, root-sprouters and clonal species are favoured in eroded lands in NE Spain. Bipolar species and annual plants might not be plastic enough to survive the high stress and frequent disturbances prevailing in such eroded areas.This study was supported by the research projects RTA 2005-00100 from the MEC (INIA) and CGL2006- 11619/HID, CGL2004-04919-C02-01/HID, REN2003-08678/ HID from the MCT, Spanish Government. J.G.C. was supported by a grant from the Government of Aragon (BMA 15/93).Peer reviewe