SER2010 Conference Excursions

(1) Mountain forests in the Mont Ventoux (Bruno Fady)

Mount Ventoux, as well as large areas in the French Southern Alps, was the scene of large scale reforestation at the end of the 19th century and during the first half of the 20th century: soil erosion was successfully controlled and forests devastated by overexploitation and overgrazing were successfully restored. This restoration is moving into a second, dynamic phase as, for several decades now, Beech (Fagus silvatica) and Silver fir (Abies alba), which had remained within residual stands, are recolonizing the planted pine (Pinus nigra, P. sylvestris, P. uncinata) stands. The new, mostly heterogeneous and mixed stands which result from this “maturation process” form a complex landscape mosaic that opens interesting prospects for the sustainability of forest trees and their associated biodiversity. However, climate change constitutes a new, very real threat, which consequences are already obvious on Mount Ventoux. The challenge for foresters is to anticipate as much as possible and to adjust forest management to this evolution. Mount Ventoux is not only a MAB reserve and a Natura 2000 site, it is also a unique and original natural scientific laboratory. The current – and inescapable in the short term – forest decline in some areas requires a new approach to ecological restoration which will benefit from current research at INRA Avignon within the framework of international networks.

(2) Salt marshs and former rice fields Camargue (François Mesléard)

The Camargue, a deltaic plain created by the sediments from the Rhône River, is one of the largest wetland areas in Western Europe. Human activities such grazing, rice growing and salt production have largely shaped this mosaic of habitats influencing the rich biodiversity, especially avifauna. After a general introduction of the Camargue context, this excursion will focus on Salinas as an example of interaction between economic activities and nature conservation. The Salinas of Giraud, a complex of 12 000 ha, represent a feeding and nesting area for many water birds including the emblematic Greater Flamingo. The restoration of a breeding site in the 1970’s boosted the Flamingo reproduction, which interruption was a threat for the whole Mediterranean population. Over time, various actions were made in favour of other patrimonial waterbirds, such as the Slender-billed Gull. The Mediterranean Salinas heritage value depends on the existence of a relative instability which strengthens the richness of these artificial wetlands. Today, Salinas are at a turning point of their history. Facing numerous constraints, some, such as the Salinas of Giraud, are becoming partially inactive. In order to conserve their biological richness, innovative measures must be found to maintain a dynamic of ad hoc habitats.

(3) Mediterranean steppe vegetation in the Crau (Elise Buisson)

The Nature Reserve of “Coussouls de Crau” is one of the last xeric steppe of Europe. This species rich vegetation host many steppic birds and some endemic arthropods. Almost 80% of the original area disappeared due to human activities (dump, military airport, cropping…). For ten years, experiments have been conducted to assess restoration techniques. The dominant perennial species (Brachypodium retusum) was transplanted on a filled quarry to assess its effect on plant community assembly. To mitigate future damages, an experiemnt was carried out on an underground pipeline where hay was transferred to accelerate steppe vegetation colonization. An abandoned 350 ha orchard is being rehabilitated in a steppic like habitat: nurses species seeding, soil excavation and translocation and hay transfer are assessed in the long term objective to restore the steppe vegetation in term of species richness, structure and composition. The field trip will firstly focus on the original steppe ecosystem and then on the experimentation plots.

(4) Salt marshs and coastal dunes near Fos-sur-Mer (Teddy Baumberger)

The expansion of the industrial area of Marseilles Fos Port Authority induces the destruction of salt marshes ecosystems, habitats and vegetation. Those ecosystems show patrimonial interests as they present typical salt marshes vegetation communities containing rare, threatened and/or endemic species. Amongst them, Limonium girardianum, which is protected at national scale, presents several populations living on current and future work sites. Indeed, since 60s, those human exploited salt marshes, for salt production, have been under high disturbance and habitat destruction pressures. In our case, the Electrabel society is building an electric power plant on large populations of Limonium girardianum. As compensatory measures, Electrabel finances for three years, a study dealing with Limonium girardianum ecology, population biology and restoration measures of their disturbed or even destructed populations on Fos-sur-mer. Limonium girardianum is a perennial herbaceous species which lives on sandy substrates of salt marshes. Our observations show that the favorable habitat of this species corresponding to intermediate micro altitudes between often flooded areas called “sansouire” and more drought and never flooded areas corresponding to more or less fixed sand dunes. This species tolerate relatively high salt concentrations, and more or less long flooded or drought periods. The aim of our study is to understand the presence of the species and its populations status in order to apply restoration, reinforcement and conservation measures taking account the industrial context and disturbance pressures. We assessed the habitat and the ecology of the species and we set in situ restoration experimentations in order to evaluate reimplantation capacities of the species according to different environmental conditions and ontogenic stages. This type of habitats within lives our species consist of dynamics ecosystems, i.e. sand dunes are not fixed for the long term. Indeed, the wind power and flood events lead to create and destruct potential habitat for Limonium girardianum. That why, we consider restoration of Limonium girardianum populations as “dynamics restoration”. We investigate those questions: do the disturbances due to human constructions favour maintain of Limonium girardianum populations in space and time? Or, did still exist populations in the future, after salt marshes infilling, hence disappearance of its habitats by dune fixation?

(5) Polluted sites in the Calanques near Marseille (Isabelle Laffont-Schwob)

With a floristic richness of exception, the Mediterranean coast is however heavily threatened by urban development and pollution. This region, known as one of the hotspot of biodiversity, is also one of the hotspot of demography growth and become one of the highly sensitive ecosystems. Thus, the Mediterranean coast engenders a paradoxical situation i.e. high endemism and rarity of the flora under environmental and anthropic growing perturbations. A appropriate illustration is given by the Marseilles South-East coast. At the beginning of the Calanques hills, Mediterranean coastal ecosystems interface pollution from abandoned industrial sites and polluted sea sprays from urban effluents at Cortiou. Occurrence of heavy metals from past industrial activities such as lead and arsenic was detected over the site. A restoration program has begun to deal with the requirement of the National Park of Calanques creation programmed to be effective in 2010. During this excursion, the pollutant fluxes at the level of the different compartments (soil, water, plants) and the biocoenose relationships will be discussed and the up-to-date project to lead to plant conservation and multi-polluted soil restoration will be explained.

(6) Fluvial margins, former channel Rhone River (Simon Dufour)

Regulated since the middle of the 19th century, to fight flooding, improve navigation and irrigation, and produce electricity, the Rhône River is characterized on a large part of its French course by a fixed landscape inherited from an active channel dynamics. As a result of morphological adjustment generated by regulation works, significant changes in flooding conditions are now observed. A rehabilitation project has been initiated by the National Company of the Rhône to combine both a decrease in local flood risk (by enlarging flood-carrying capacity) and an enhancement of geomorphological and ecological properties of the margins into the reach (sediment reworking, pioneer species regeneration…). The aim of this field trip is to present the project developed since 2007 for fluvial margins and former channel rehabilitation along the lower Rhône River reach. Because of this reach specificities (i.e. multiplicity of issues and stakeholders), a particular framework has been developed. The rehabilitation project of the lower Rhône River concerns a 70 km length reach where several issues are overlaid. On one hand, the instream introduction of sediments stored in the floodplain could cause negative consequences to others aspects such as private land erosion, navigation, and polluted sediments introduction. On the other hand, this action could benefit sediment supply to coastal area or ecological functioning of the floodplain. Moreover, the vulnerability to inundation is concentrated only in the first kilometres of the reach and not in the Camargues delta. To increase erosion, channel gradient is also more favourable upstream from Arles. As a result, few sites appear to be potentially rehabilitated (2 to 4 sites along 70 km). One site is going to be used to discuss several issues raised by the project: how to definel reference conditions? How can we choose sites to test the actions? How to design these actions? Which kind of ecosystems can be expected under Mediterranean climate (composition, recovery rate, presence of exotic species…)?

(7) Mediterranean wetland of the Vigueirat (Elodie Debize)

The Marshlands of Vigueirat are a mosaic of Mediterranean natural wetland habitats with a great biological richness (290 bird species have been recorded, including many rare species with high conservation value). The field trip will lead you to be actively involved in an invasive species management program on this ecosystem: the water primrose’s control and removal. Water primrose (Ludwigia spp, Onagraceae family) is an aquatic weed originally from South America. This species reduce biodiversity and degrade water quality by decreasing pH and dissolved oxygen content. Moreover, water primrose can quickly block waterways, interfering with human uses of water systems such as navigation, fishing, hunting and pasturage. They create a serious problem for the aquatic environment, which they colonise to the detriment of the local flora and fauna.

(8) Frioul Archipelago near Marseille (Jérôme Orgeas)

The Frioul archipelago encompasses four islands counting for a total of 200 hectares, and distant of 4 km of Marseille. Before being part of the town, the archipelago has experienced a heavy past of history and was early established as an outpost of Marseille military defence. This long occupation by humans has now turned into mass tourism activities and urban expansion. The human pressure has raised conservation issues for a great number of valuable species found on the set of islands. Many birds and plants are indeed rare and protected, which most of them show sharp adaptations to the harsh coastal Mediterranean environments. The conference field trip will propose a walk around the main two islands of the archipelago (Pomègue and Ratonneau) where history, ecology and conservation issues will be presented across few stops. Impacts of human-use on native species and the spread of invasive ones (rats, rabbits and feral cats) will be particularly highlighted. Management policy of this original area will be discussed as part of conservation programs and future protection.

(9) Restoration of Mediterranean riparian vegetation in the Arboretum of Beauregard (Stéphanie Mari)

The Beauregard Arboretum serve as an experimental site for research which has been conducted with the Porquerolles Botanical Conservatory for the past four years, for genetic amelioration and improvement of the natural landscape for damaged natural habitats (riverbank woods, hedges and related habitats). The positive results obtained by this program will be a reference; showcasing what can be done with native vegetation fo (1) salvaging vanishing natural habitats or genetic amelioration of damaged habitats, (2) reviving and restoring habitats upset by infrastructure installlations (roads, etc.) and (3) ornamental planting adapted to the soils, climates and landscapes of the Provence area. More about the actions of the General Council of Vaucluse in environnement, click here.