The status of the coral reefs of French Scattered Islands in the Indian Ocean

Together with La Réunion and Mayotte Islands, Scattered Islands make up French Indian Ocean Territories (FIOT) which all possess highly ecologically sensitive natural habitats of major value for migrant species (turtles, seabirds, mammals). As a contribution to the national action plan of IFRECOR (French initiative on coral reefs) we set up during the period 2002-2005 a survey and monitoring program in order to increase the knowledge of the still poorly known coral reefs of these islands scattered from North to South in the Mozambique Channel and in central Indian Ocean. Results were particularly focused on the geomorphological mapping of shallow marine habitats and on a structural and functional approach of fish, coral and mollusc communities. Additional approaches with rapid assessment methods remained non exhaustive but nevertheless allow a first integrated diagnosis of the patrimonial value of the coral sanctuaries of Scattered Islands and to propose decision-making tools for identifying applied and fundamental axes of research as well as actions of monitoring adapted particularly to vulnerability factors and global warmingAvec l'île de la Réunion et Mayotte, les îles Éparses constituent les îles Françaises de l'océan Indien, lesquelles possèdent toutes des milieux naturels à sensibilité écologique forte et d'intérêt majeur pour des espèces migratrices (tortues, oiseaux marins, mammifères). Dans un contexte de mauvaise connaissance des récifs coralliens de ces îles éparpillées du Nord au Sud du canal du Mozambique et au centre de l'océan Indien occidental, nous avons réalisé de 2002 à 2005 un programme axé sur la connaissance et la surveillance des récifs, en vue de contribuer au plan d'action national de l'Initiative Française sur les Récifs Coralliens (IFRECOR). Les résultats concernent tout particulièrement la cartographie géomorphologique des milieux marins peu profonds ainsi qu'une approche structurelle et fonctionnelle des peuplements de poissons, coraux et mollusques. Les approches complémentaires menées selon des protocoles d'évaluation rapide restent non exhaustives mais permettent aujourd'hui de disposer d'un premier diagnostic intégré de la valeur patrimoniale des sanctuaires coralliens des îles Éparses et de proposer une aide à la décision pour identifier des axes de recherche appliquée et fondamentale, des mesures de gestion adaptées notamment aux facteurs de vulnérabilité tel que le réchauffement global

Le blanchissement des coraux à la Réunion en 2009. Rapport ARVAM/PARETO/Université de la Réunion/MNHN pour le compte du GIP Réserve naturelle marine de la Réunion

Rapport sur Le blanchissement des coraux à la Réunion en 2009. Rapport ARVAM/PARETO/Université de la Réunion/MNHN pour le compte du GIP Réserve naturelle marine de la Réunio

Les récifs coralliens de La Réunion en 2007 : état des lieux et réseau de suivi = Coral reefs of Reunion Island in 2007 : status report and monitoring network

Reunion Island is 2500 km(2) and belongs to the outermost regions of European Union (EU). The population attained 774 600 inhabitants in 2004 with 25% living in the western part of the island, 80% in the littoral zone (called >), The gross domestic product (GDP) per capita is less than 50% of the mean index of the EU. The rate of unemployment was of 33% in 2004. Coral reef ecosystems extend over 12 km(2) along 25 km of the west and south coasts of the island. In addition to the natural influence of climatic events (global change) coral reef ecosystems are impacted by direct and indirect influences of the increase of human population. Direct impacts are mainly due to human over frequenting of reef flats and over fishing. Indirect impacts are due to urbanization and to industrial, agricultural and urban pollutions. The competence in marine environment is assumed by an administration (Direction Regionale de l'Environnement). Researches on coral reefs are run by research institutes and NGO. The first coral reef monitoring network was set up in 1998 on the Saint-Gilles/La Saline reef. Since then, it was extended to the three other main reef units (Saint-Leu, Etang-Sale, Saint-Pierre) and the data are gathered since 2001 by ecoguards of the association >, with the partnership of the university (Laboratoire d'Ecologie Marine). Data are stored in a database (COREMO) and analysed by ARVAM (Agence pour la Recherche et la Valorisation Marine). The operation is funded both by the state administration and a local administration (Conseil Regional). Reunion Island is a part of the South-West Indian Ocean node of the Global Coral Reef Monitoring Network (GCRMN). It is regularly involved in the writing of the >. At the same time another network involving stakeholders is built using the Reef Click protocole. At the present time, coral reefs of Reunion Island are deteriorated. If the density of the targeted species of fish has not changed since 1999, the surface of live corals has shown a significant decrease on half of the 14 stations, particularly after two bleaching events in 2003 and 2004. The various negative impacts due to human activities contribute to weaken these ecosystems and to decrease their resilience. Hence, they are less and less able to resist exceptional climatic events (hurricanes, swells) and the bad impacts of global change (bleaching). To face to the stake of long term development, 75% of the reef units of the island are protected since February 2007 by the status of > (35 km(2) of marine protected area)

World seas : an environmental evaluation. Vol. II : the Indian Ocean to the Pacific

In the South Indian Ocean, French territories include Reunion (Mascarene archipelago), Mayotte (Comoros archipelago) and the remote Iles Eparses in the Mozambique Channel (Glorieuses, Juan de Nova, Bassas da India, Europa), and Tromelin, North-East of Madagascar. Their coral reefs are varied, from 18 km2 of fringing reefs in Reunion to 1500 km2 of fringing, barrier and double barrier reefs in Mayotte, caye reefs in Glorieuses and Tromelin to atolls in Juan de Nova, Bassas da India and Europa. Pressures on them vary from 850,000 inhabitants in Reunion to no permanent inhabitants in Iles Eparses. Annual monitoring of Reunion and Mayotte shows a gradual decrease in coral cover and fish biomass, due to overfishing. Yet an exceptional biodiversity is recorded in Mayotte, mainly due to its geographical position at the center of the WIO coral triangle, and the variety of reef habitats. In the remote Iles Eparses, more recent monitoring showed a remarkable state of coral reefs and their exceptional fish biomass. These coral reefs are under human threats mainly due to coastal development and land-based pollution, except for Iles Eparses. Climate change has an impact through coral bleaching whose effects are stronger for reefs in the North of the Mozambique Channel. The impact of the 2016 bleaching event was variable on islands but most corals showed signs of resistance with a good recovery of coral colonies. In order to limit degradation and overexploitation of reef resources, national marine protected areas (MPAs) have been made in all French islands: 2007 in Reunion, 2010 in Mayotte, and 2012 in Glorieuses while all Iles Eparses have been under protection for more than 20 years. Despite this, Iles Eparses are beginning to suffer from illegal fishing, including collection of holothurians and perhaps shells, particularly since 2012. Long-term monitoring is essential to describe trends in coral communities in the context of increasing human impact and climate change

Coral reef monitoring in the Iles Eparses, Mozambique Channel (2011-2013)

Monitoring of coral reefs has become a major tool for understanding how they are changing, and for managing them in a context of increasing degradation of coastal ecosystems. The Global Coral Reef Monitoring Network (GCRMN) has near-global coverage, but there are few remote sites free of direct human impact that can serve as reference sites. This study provides baseline data for the French Iles Eparses in the Mozambique Channel, Western Indian Ocean (WlO), whose coral reefs are little known owing to their limited accessibility, and have been free from fishing pressure for over 20 years. Surveys of coral reef health and fish community structure were undertaken at four of the islands (Europa, Bassas da India, Juan de Nova and Glorieuses) in 2011-2013. Monitoring was conducted using standardized GCRMN methods for benthos and fish communities, at the highest taxonomic level. Benthic cover showed a latitudinal gradient, with higher coral cover and conversely lower algae cover (60% and 14% respectively) in the south of the Mozambique Channel. This could be due to the geomorphology of the islands, the latitudinal temperature gradient, and/or the history of chronic stress and bleaching events during the last decades. Fish also showed a latitudinal gradient with higher diversity in the north, in a center of diversity for the western Indian Ocean already recognized for corals. An exceptional biomass fish was recorded (approximately 3500 kg/ha excluding sharks, compared to a maximum of 1400 kg/ha elsewhere in the WIO). The presence of large predators and sharks in all the islands as well as the absence of fleshy benthic algae were indicators of the good health of the reef systems. Nevertheless, these islands are beginning to experience illegal fishing, particularly in the north of the Mozambique Channel, demonstrating their vulnerability to exploitation and the need to protect them as reference sites for coral reef studies, including of climate change impacts, for the region and globally

Caractérisation de l'état de référence biologique des masses d'eau côtières (de La Réunion) au regard de la Directive Cadre sur l'Eau. Rapport Ifremer/ARVAM/ECOMAR /Pareto pour DEAL de La Réunion

Rapport sur la caractérisation de l'état de référence biologique des masses d'eau côtières (de La Réunion) au regard de la Directive Cadre sur l'Eau. Rapport Ifremer/ARVAM/ECOMAR /Pareto pour DEAL de La Réunio

Assessing coral reef biodiversity at the Glorieuses Islands Marine Park (Scattered Islands, SW Indian Ocean) with identification of priority zones for conservation

International audienc

World Econ.

Remittances can transmit volatility from host to home countries for some common patterns of diaspora's geographical distribution. In a migration portfolio model, the overall risk of volatility of any set of diaspora location is decomposed into a contagion and a concentration risks: a diaspora located in more volatile destinations induces a higher contagion risk, while a diaspora located in few destination countries increases the concentration risk. A series of estimations on a large panel of developing countries over 1995–2015 provide evidence for these two risks. Estimation of a structural model confirms that the geography of diaspora has an indirect impact on the origin country's aggregate instability through remittances