Factors affecting the success of early salt-marsh colonizers: seed availability rather than site suitability and dispersal traits

We evaluated the process of salt-marsh colonization in early successional stages of salt-marsh restoration and investigated how the sequence of species establishment related to different success factors. Vegetation data were collected by permanent plots from the restoration site and adjacent, reference salt marshes during three consecutive periods. Seed length, width and mass were used as dispersal traits, and Ellenberg moisture, salinity and nutrient indices as indicators of site suitability. Seed production in the reference site and seed bank in the restoration site were also investigated. The establishment of salt-marsh species within the restoration site was rapid (less than 5 years). The cover of plant species was not correlated between the restored and the reference sites at the first year of restoration, but this correlation was significant during the following years. Seed availability was more important in explaining the sequence of species establishment than salt and nutrient-limitation tolerance. The first colonizers are known as massive seed producers, with shorter seed length and lower seed mass, which probably increased buoyancy. Among dispersal and site traits, seed length and mass, and in a less extent salinity and nutrients, indicated a relationship with new colonizers. Despite few species have not (yet) appeared in vegetation and seed bank in the restoration site, the existence of an existing salt marsh adjacent to the restoration site is shown to be vital for fast colonization of newly created intertidal areas

Restauration à l'échelle du paysage : le salut de la biodiversité des pelouses sèches européennes ?

International audienceSpecies-rich dry grasslands in Europe have suffered losses in extent and diversity in the last 50 years. Their conservation requires maintenance of remaining grasslands and restoration of lost or damaged grasslands. We report on landscape-level restoration studies and case studies from dry grasslands in contrasting regions of Europe to discuss the strengths and weaknesses of the approaches, the results achieved and the costs and benefits. We conclude that landscape-level restoration offers exciting new opportunities to restore biodiversity and landscape connectivity in Europe’s dry grasslands. There are now drivers for large-scale restoration written into the 2020 targets of the Convention on Biological Diversity and the European Biodiversity Strategy. However, a more integrated approach to large-scale ecological restoration is needed for the development of policy tools to achieve the greatest benefits from restoration at the landscape scale

Restauration à l'échelle du paysage : le salut de la biodiversité des pelouses sèches européennes ?

International audienceSpecies-rich dry grasslands in Europe have suffered losses in extent and diversity in the last 50 years. Their conservation requires maintenance of remaining grasslands and restoration of lost or damaged grasslands. We report on landscape-level restoration studies and case studies from dry grasslands in contrasting regions of Europe to discuss the strengths and weaknesses of the approaches, the results achieved and the costs and benefits. We conclude that landscape-level restoration offers exciting new opportunities to restore biodiversity and landscape connectivity in Europe’s dry grasslands. There are now drivers for large-scale restoration written into the 2020 targets of the Convention on Biological Diversity and the European Biodiversity Strategy. However, a more integrated approach to large-scale ecological restoration is needed for the development of policy tools to achieve the greatest benefits from restoration at the landscape scale

Importance of regional species pools and functional traits in colonisation processes: predicting re-colonization after large-scale destruction of ecosystems

Contains fulltext : 66034.pdf (publisher's version ) (Closed access)8 p

Effect of topsoil removal and plant material transfer on vegetation development in created Mediterranean meso-xeric grasslands

International audienceQuestion: Can plant material transfer combined with topsoil removal be an efficient method of restoring Mediterranean meso-xeric grassland plant communi-ties? Does increasing topsoil removal depth increase the success of plant material transfer establishment? Location: The Camargue, Rh^ one delta, France. Methods: A small-scale restoration experiment involving Mediterranean meso-xeric grasslands was conducted in a former rice field area. During 3 yr, plant species richness and composition were compared on permanent plots subject to the following four treatments: 5 cm topsoil removal, 20 cm topsoil removal, 5 cm topsoil removal with plant material transfer, and 20 cm topsoil removal with plant material transfer. Additionally, the seed bank at 0-to 5-cm deep, at 5-to 20-cm deep and at 20-to 40-cm deep were studied in order to evaluate the effect of topsoil removal. Results: After 4 mo, species richness, number of target species and similarity to the reference Mediterranean meso-xeric grassland significantly increased with plant material transfer relative to the no transfer treatment (topsoil removal without transfer). However, we found no significant difference in plant species number between the two depths of topsoil removal. This can be explained by the absence of any variation in soil seed bank between 5 cm and 20 cm. The species richness and number of target species decreased significantly in transfer treatment between the first and the second monitoring. Despite this general decrease in the first year, the plant material transfer treatment showed significantly more target species than the no transfer treatment and a higher similarity to the Mediterranean meso-xeric grassland. Conclusion: In order to restore a Mediterranean meso-xeric grassland plant community, plant material transfer combined with topsoil removal appears to be a relevant method. Removing 5 cm of topsoil eliminates half of the density of the undesired seed bank in a former rice field. However, the ability of target species to establish and persist in restored vegetation communities will require good management. Conditions with low competition in early stages of succession seem to be essential for transferred species to persist, and appropriately timed grazing and adequate stocking rates will be needed to limit the negative effects of competition