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Resprouting is a mechanism that allows individual plants to persist in disturbance-prone ecosystems. It is often considered a binary trait, defi ning species as resprouters or non-resprouters. Although this dichotomous classifi cation accounts for a high proportion of the interspecifi c variability in resprouting, it does not account for the intraspecifi c variability, as not all individuals of resprouting species successfully resprout, even if they are subject to a similar disturbance. To ascertain the causes of the intraspecifi c variability in resprouting we propose a conceptual model that disaggregates the process of resprouting into three sequential steps: initial ability to resprout, resprouting vigour and post-resprouting survival. To test this model, we clipped 151 plants of three resprouting species ( Anthyllis cytisoides, Globularia alypum and Linum suff ruticosum ) and, for each individual, we analysed the carbohydrate (starch and soluble sugars) and nutrient (N and P) concentrations in the roots at the moment of the disturbance (clipping all aboveground biomass). We then monitored initial ability to resprout, resprouting vigour and post-resprouting survival in each individual during a one-year period. Anthyllis showed high initial ability to resprout and high post-resprouting survival. Globularia and Linum had low final resprouting success, mainly due to their low post-resprouting survival, but also to the low initial ability to resprout in Linum . All three species showed variable resprouting vigour. Our results suggest that resprouting success is limited by different phases of the process of resprouting, depending on the species. Intraspecific variability in resprouting supported the importance of: a) the pre-disturbance state of the plant (i.e. plant size and stored resources) on the initial ability to resprout and on the resprouting vigour, and b) the initial post-disturbance capacity to acquire resources (i.e. resprouting vigour) on the post-resprou

Native species arise as an alternative to improve the poor success of traditional hydroseeding with commercial species in degraded areas. The objectives of this study were to (1) establish a procedure to select suitable native species for roadslope revegetation, (2) validate the procedure by means of field sowing experiments, and (3) assess cost effectiveness of the use of native species in hydroseeding as regards commercial ones. Vegetation surveys were performed in semiarid roadslopes of East Spain and species success evaluated according to abundance and frequency. A list of potentially suitable species for revegetation was produced and a subset of species selected and hydroseeded to check their suitability in hydroseeding. Cost effectiveness of the use of native species was estimated. Results support the suitability of the procedure for the selection of native species. Vegetation cover produced by the hydroseeded mixture of native species was high (between 43 and 70% throughout the 4 years) and was 4-20 times higher than the cover produced by a standard commercial seed mixture. The price of the selected seed mixture was 30 times that of the commercial one, but the cost of relevant ecological advantages provided by the use of native species was only twice that of the commercial species on the basis of cost effectiveness assessment. Practical consequences for restorers, policymakers, and practitioners are discussed, and the use of native species is encouraged to improve revegetation success of roadslopes and similar slope types especially in semiarid and arid environments.

Question: What is the main ecological process determining species assemblage in roadside herbaceous plant communities?, Location: Roadside slopes (roadcuts and embankments) in the south (Málaga, mesic Mediterranean) and east (Valencia, dry and continental) of the Iberian Peninsula., Methods: We identified 417 plant species, from which we selected the 331 most abundant (within the 70th abundance percentile) at each site. We compiled information on 28 functional traits and on the biogeographic range of each of these 331 species. We quantified the phylogenetic signal of each trait for the species of each community and determined the number of functional convergences or divergences over the phylogenetic tree for each of the four situations (roadcuts and embankments in the two sites)., Results: There was a significant phylogenetic signal in many traits, being positive in Valencia embankments and negative in Valencia roadcuts with almost no signal in any type of slope in Málaga. Each trait was significantly correlated with 20% - 35% of all other traits but correlation coefficients were low. No significant phylogenetic signal was found for the species’ distribution range in any of the four communities studied, which might be the consequence of the complex mixture of biogeographic origins of the species found in these communities., Conclusion: The lack of a phylogenetic signal in most traits in Málaga, a climatically favourable locality, suggests that competitive exclusion was the main process involved in the assemblage of these communities. The significant and either positive or negative phylogenetic signal (in embankments and roadcuts respectively), the latter coupled with a significant number of functionally convergent nodes in the phylogenetic tree, suggests that environmental filtering is the most likely process involved in the harsh locality of Valencia.

The importance of neighboring vegetation as a seed reservoir for spontaneous colonization of adjacent road slopes was analyzed in a semiarid region of east Spain. Two independent methodological approaches were used to examine the relative contribution of seed from neighboring vegetation and the efficiency of different seed dispersal strategies in plant colonization. We first used a randomization test to compare floristic similarity between road slopes, neighboring flora, and local flora (the regional species pool found in the same climate and soil conditions as the road slopes). Second, we compared seed dispersal mechanisms of road slope vegetation with those of the surrounding area using frequency analysis. Species composition of road slopes was more similar to that of the flora of adjacent surrounding areas than expected by chance. Anemochorous (wind-dispersed) plants were over-represented in road slopes 8 years after road slopes were built. We concluded that seed dispersal from neighboring vegetation is an important factor in the vegetative colonization of road slopes. However, this initial species pool was also strongly shaped by the harsh environmental conditions of roadcuts and southern aspect. These results have important implications in road slope restoration because they suggest that naturally vegetated areas should be maintained adjacent to road slopes to enhance seed immigration from species adapted to local site conditions, which will accelerate the successional process. The application of this single reclamation strategy and mixed strategies that combine the use of natural colonization and soil amendment for road slope restoration in Mediterranean environmental conditions is discussed.

Erosion is one of the main problems in roadfill restoration. Revegetation is widely used as a method to reduce erosion rates, and it is often carried out through hydroseeding. In semiarid Mediterranean conditions, this approach to revegetation often produces poor results due to climatic limitations. We evaluated whether (1) spreading topsoil and (2) hydroseeding with local rather than commercial species mixtures could improve the vegetative cover of roadfills. The study was carried out in 24 plots over a 20-month period. At the end of the study, vegetation cover was higher in topsoiled plots (38.8%) than in nontopsoiled plots (21.5%). Locally selected species produced higher vegetative cover (61.1%) than did standard commercial species (52.2%). After 20 months, the erosion index was not different among any treatment probably due to the low sensitivity of this variable. These results suggest that amendment of soils through the addition of topsoil is an important technique in roadfill revegetation in Mediterranean environments. Additionally, hydroseeding with local species will produce better vegetative cover on roadfills than does hydroseeding with available commercial species.