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Question: Which biological traits (persistence, regeneration, dispersion traits and resource requirements) may explain the distribution of woodland flora along an urban–rural gradient? Location: The study was carried out in three medium-sized conurbations of north-western France: Angers, Nantes and Rennes. Methods: We sampled the vegetation of 36 small woodlands of about 1.5 ha composed of non-planted vegetation along an urban–rural gradient. We characterized the position of woodlands along the urban–rural gradient by examining adjacent land cover. By using an ordination analysis (RLQ), we analysed which traits out of –23 tested were related to the contrasted distribution of species along the urban–rural gradient. Results: Species that are more likely to be found in urban woodlands than rural woodlands have different persistence traits (higher specific leaf area, more often rosette or semi-rosette form, less underground vegetative multiplication), resource requirements (affinity for base-rich and fertile soils) and regeneration traits (short life-span). Dispersion traits were not related to the distribution of species along the urban–rural gradient. Conclusions: Our approach identifies traits that can help to determine the vulnerability of forest species as a result of the environmental changes that follow urbanization. Limiting the influence of the urban environment on habitat quality (particularly disturbance and soil enrichment) is likely to be of major importance in maintaining the plant biodiversity in woodlands.

Dunes, which account for 13% of the Ille et Vilaine north Brittany coast, France, were degraded by high tourist pressure, and they were restored from 1988 onward. Ten years after commencing work an assessment of the restoration was made on three dunes: Les Chevrets, L'Anse Du Guesclin, and Le Verger. Annual monitoring of the vegetation and dune morphology provided an opportunity to study the restoration process. The dune front, which is similar to a reference pioneer dune, lies in front of the mobile dune. The highest part of the dune is an advanced stage of mobile dune. The restoration of the fixed rear dune was accomplished neither in terms of vegetation composition nor in terms of species richness. The vegetation parameter study allows differentiation between the dune front, the dune summit, and the rear dune. The variation in species richness and floristic composition from one zone to another can be explained by abiotic factors such as salinity and the accretion of sand. The restoration was satisfactory in terms of the geomorphology. Marram grass is a good tool for restoring the topography, but it will take a very long time to restore the conservation value of the dune.

The sand-dunes of Quiberon was chosen as a pilot site to investigate experimentation in conservatory management. Sand burial is necessary to conserve the semi-fixed dune which is a transitory dynamic stage. In the fixed dune, low disturbances benefit the vegetation diversity while heavy ones create serious injury. An opening of the milieu can restore very fast but a naked substrate is difficult to heal. The deposition of gorse branches is then efficient to facilitate the restoration. The fixed dune biodiversity is linked to human activities. Disturbances, natural or not, may be used as management tools. To cite this article: S. Lemauviel et al., C. R. Biologies 326 (2003).

As a result of the large increase in tourist pressure, trampling has become an important factor in the degradation of natural areas and particularly Atlantic Heathlands. In this study, the resistance of dry and mesophilous heathlands was studied experimentally, under different environmental conditions. The trampling was applied in winter, and in summer in periods of wet and dry weather. The types of heathlands studied appeared to be moderately resistant to trampling. Mesophilous heathlands were on the whole more sensitive to trampling than dry heathlands. The resistance of these communities and of their component species varied greatly in relation to season and weather conditions. For example, Erica ciliaris was more resistant to trampling in summer than in winter, and in summer Erica cinerea was more sensitive to trampling in wet weather than in dry conditions. The analysis of the resistance of species showed that heather species were more sensitive than the rest of the plant cover. These heathers are characteristic species of the heathlands that were studied. The definition of acceptable visitor pressure thresholds must not be based on the index of resistance of the whole community, but on that of the characteristic species, in this case heathers. The aim of visitor pressure management must be to preserve the vegetation structure and not just simply plant cover.