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L’évaluation de la pertinence des mesures d’atténuations proposées par une étude d’impacts lors d’un projet d’aménagement s’effectue par la mise en place de veilles écologiques. Néanmoins, ce type de suivis est rare puisqu’aucune législation ne l’impose. Focus sur la plaine de Crau où une veille écologique a été mise en place afin d’évaluer les mesures compensatoires et les mesures d’atténuations proposées par une étude d’impact lors de l’enfouissement de canalisations sur un écosystème sensible.

Même s'il suscite encore de nombreux débats, le principe de compensation écologique pour les dégâts causés à la biodiversité lors de projets d’aménagements a finalement été adopté en mars dernier dans le cadre de la loi « Biodiversité ».À travers l'exemple de la réhabilitation écologique et pastorale du verger de Cossure en plaine de Crau, première expérimentation française de compensation écologique par l'offre, les auteurs s'intéressent ici au bilan écologique et économique de l'opération pour en dégager les effets positifs, mais également les dysfonctionnements et les limites.

Le premier site naturel de compensation français a été inauguré le 11 mai 2009 sur le site d’un verger abandonné dans la plaine de Crau (Bouches-du-Rhône, France). Cette opération avait notamment pour objectif d’expérimenter le premier mécanisme d’offre de compensation français via la réhabilitation d’une végétation herbacée permettant le retour des oiseaux steppiques emblématiques de cet espace. Impliqués dans le comité local de pilotage, des écologues ont conseillé les techniques de réhabilitation et expertisé leurs effets sur la biodiversité tout en réalisant des recherches expérimentales pour étendre la restauration à la végétation et à certains groupes d’insectes. Après 7 années de suivis, les résultats montrent que la réhabilitation a bien permis la création d’une végétation favorable au retour de l’avifaune steppique mais le succès des expérimentations de restauration ne peut pas encore être définitivement prédit sur le long terme. Ces résultats soulignent les difficultés scientifiques et techniques de la restauration et limitent donc le mécanisme de compensation à la réhabilitation de certaines composantes ou fonctions.

Monomorium carbonarium (Smith, 1858) is reported for the first time from south-eastern France. This new localization indicates that this invasive insect may be more widespread over the country. [ABSTRACT FROM AUTHOR]

Defining a reference ecosystem for ecological restoration project is an essential step. The reference can correspond to the historical ecosystem, can be defined to solve environmental issues or can correspond to a socioecosystem. For the restoration of the Cassaïre site in the Camargue delta in southern France, the reference ecosystems chosen are: Mediterranean temporary wetlands and Mediterranean meso-xeric grasslands. The choice of these two reference ecosystems appears logical considering their contribution to regional biodiversity. Temporary wetlands and meso-xeric grasslands are rare, adapted to the Mediterranean climate, seriously endangered and host a high species richness. They are potentially achievable restoration targets because patches of these ecosystems remain in the Camargue area and close to the Cassaïre site. Moreover, an ecological history approach reveals deep human imprints on ecosystems and ensures that historical restoration targets (the state prior to human impacts) cannot be reached, because they are associated with hydraulic functioning (flooding of the Rhône and Durance) that no longer exists. The restored site is planned to be suitable for livestock grazing, thus presenting a new agricultural opportunity, while simultaneously offering new services, such as hunting. [ABSTRACT FROM AUTHOR]

For each restoration project, it is essential to define a reference ecosystem towards which ecological restoration aims. Historical information may be useful in the construction of the reference model and in finding out about the type and degree of disturbances that have caused degradation on the site, as legacies of past human land-uses have been shown to be major determinants of vegetation and plant diversity even in the very long term. The aim of this paper is the retrace the history of three sites where restoration protocols were tested, to better apprehend the potential reference ecosystems as well as the disturbances that degraded them. To do so, we first compiled information on the reference ecosystems at the landscape scale. Then, we compiled historical and agricultural information at the scale of the sites from local historical documents, historical reviews and aerial photographs. The three sites most likely were grasslands or oak savannas before European settlement. Grasslands used to cover 8.9 million ha in California. They were species-rich grasslands managed with fire by the native people and grazed by native ungulates. Early settlers introduced cattle grazing and changed fire regimes. Later on, many grasslands were converted to cultivation. All three sites were used for ranching and sometimes overgrazed. At least two of them were cultivated, probably leading to restoration being harder there, as plowing eliminates perennial species, destroys the seedbank, changes soil characteristics. [ABSTRACT FROM AUTHOR]

The article focuses on the challenges posed by the invasive species Ailanthus altissima, particularly its alarming expansion in the Chréa National Park in Algeria due to activities over the past fifty years. Topics covered include the efforts to understand and manage its progression, advancements in methodologies for species monitoring, and the use of satellite imagery, emphasizing the importance of public policy and scientific support to prevent the rapid disappearance of certain ecosystems.

The article presents the discussion on scientific knowledge on climate and environmental changes affecting countries around the Mediterranean basin investigating populations of beetles predating aphids and slugs in a semi-arid region of northeastern Algeria for encouraging biological control.