Suchergebnisse

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 reviewed

9 páginas, 4 figuras, 2 tablas.-- El PDF es la versión post-print. ; [Background and Aims]: The objective of this study was to test whether the mean values of several root morphological variables were related to the ability to develop root-borne shoots and/or shoot-borne roots in a wide range of vascular plants. [Methods]: A comparative study was carried out on the 123 most common plant species from eroded lands in north-east Spain. After careful excavations in the field, measurements were taken of the maximum root depth, absolute and relative basal root diameter, specific root length (SRL), and the root depth/root lateral spread ratio on at least three individuals per species. Shoot-rooting and root-sprouting were observed in a large number of individuals in many eroded and sedimentary environments. The effect of life history and phylogeny on shoot-rooting and root-sprouting abilities was also analysed. [Key Results]: The species with coarse and deep tap-roots tended to be root-sprouting and those with fine, fasciculate and long main roots (which generally spread laterally), tended to be shoot-rooting. Phylogeny had an important influence on root system morphology and shoot-rooting and root-sprouting capacities. However, the above relations stood after applying analyses based on phylogenetically independent contrasts (PICs). [Conclusions]: The main morphological features of the root system of the study species are related to their ability to sprout from their roots and form roots from their shoots. According to the results, such abilities might only be functionally viable in restricted root system morphologies and ecological strategies. ; This study was supported by the Spanish Ministry of Science and Technology, projects AMB93-0806, REN2002-02635/ GLO and RTA 2005-00100. J. G. C. and S. P. were supported by a grant from the Government of Aragon (BMA 15/93) and a FPU scholarship (AP-2001-2311, MEC, Spain), respectively. ; Peer reviewed