Functional Redundancy Patterns Reveal Non-Random Assembly Rules in a Species-Rich Marine Assemblage

The relationship between species and the functional diversity of assemblages is fundamental in ecology because it contains key information on functional redundancy, and functionally redundant ecosystems are thought to be more resilient, resistant and stable. However, this relationship is poorly understood and undocumented for species-rich coastal marine ecosystems. Here, we used underwater visual censuses to examine the patterns of functional redundancy for one of the most diverse vertebrate assemblages, the coral reef fishes of New Caledonia, South Pacific. First, we found that the relationship between functional and species diversity displayed a non-asymptotic power-shaped curve, implying that rare functions and species mainly occur in highly diverse assemblages. Second, we showed that the distribution of species amongst possible functions was significantly different from a random distribution up to a threshold of ∼90 species/transect. Redundancy patterns for each function further revealed that some functions displayed fast rates of increase in redundancy at low species diversity, whereas others were only becoming redundant past a certain threshold. This suggested non-random assembly rules and the existence of some primordial functions that would need to be fulfilled in priority so that coral reef fish assemblages can gain a basic ecological structure. Last, we found little effect of habitat on the shape of the functional-species diversity relationship and on the redundancy of functions, although habitat is known to largely determine assemblage characteristics such as species composition, biomass, and abundance. Our study shows that low functional redundancy is characteristic of this highly diverse fish assemblage, and, therefore, that even species-rich ecosystems such as coral reefs may be vulnerable to the removal of a few keystone species

Checklist of the shore fishes of Europa Island, Mozambique Channel, southwestern Indian Ocean, including 302 new records

Die Checkliste der Fische der Insel Europa (Kanal von Mosambik, südwestlicher Indischer Ozean) enthält 389 Arten in 62 Familien. 302 Arten werden zum ersten Mal von der Insel Europa beobachtet. Alle Fischarten sind authochthon; es wurden keine durch den Menschen eingeführten oder eingeschleppten Arten gefunden. Alle Fischarten sind marin; die artenreichsten Fischfamilien sind die Labridae, Pomacentridae, Serranidae, Gobiidae und Acanthuridae. Die Fischfauna der Insel Europa ist typisch für küstenferne, niedrige Inseln im südwestlichen Indischen Ozean. Zoogeographisch haben 75,1 % der nachgewiesenen Fischarten eine großräumige indo-pazifische Verbreitung, 3,3 % der Arten werden in allen tropischen Meeren gefunden, und 19,5 % der Arten sind im Indischen Ozean endemisch, davon 9,2 % nur im westlichen Indischen Ozean und 2,6 % im südwestlichen Indischen Ozean. Es wurden keine endemischen Fischarten bei der Insel Europa gefunden

Impact of the Use of a Teaching Toolbox in an Awareness Campaign on Children's Representations of Coral Reefs

Environmental education for children is one of the fundamental tools required to reverse the degradation of our environment and the biodiversity erosion. Currently coral reefs are part of the vulnerable ecosystems which are most threatened by human activities and climate change. Responding to these pressures demands decisions at multiple scales, based on solid knowledge of coral reefs but also on strengthened awareness to build adaptive management solutions. Here we evaluate the impact of an environmental awareness campaign for children using a teaching toolbox developed by scientists (MARECO “The Coral Reef In Our Hands”). To assess this impact before and after using the toolbox, we analyzed the evolution of children's representations of coral reefs through drawings. This study was carried out in New Caledonia, focusing on five elementary schools in different social and cultural contexts (urban, rural and coastal). Two hundred and forty-eight drawings were made by children. The drawings were analyzed quantitatively using multivariate statistical analyses which reveals a diversity of representations in children with diverse sociocultural profiles, but also between schools, emphasizing that relationships with nature and marine environment vary according to direct and indirect experiences related to reefs. Furthermore, our results pointed out relevant differences in coral reef representations before and after the use of MARECO, particularly regarding their knowledge of reef biodiversity associated with multicolored organisms and the connection of coral reef with environment, the number of colors being used as a proxy of this holistic vision developed by children. These results point out the performance of MARECO as a playful tool to transfer scientific knowledge to children. Coral reef conservation is intimately linked to an awareness in young generations of the environmental challenges of tomorrow. To be agents of change in a sustainable world, children must be engaged in a fun, rigorous, action-oriented and socially responsible learning process such as the ones developed in participatory approaches

Functional over-redundancy and high functional vulnerability in global fish faunas on tropical reefs

When tropical systems lose species, they are often assumed to be buffered against declines in functional diversity by the ability of the species-rich biota to display high functional redundancy: i.e., a high number of species performing similar functions. We tested this hypothesis using a ninefold richness gradient in global fish faunas on tropical reefs encompassing 6,316 species distributed among 646 functional entities (FEs): i.e., unique combinations of functional traits. We found that the highest functional redundancy is located in the Central Indo-Pacific with a mean of 7.9 species per FE. However, this overall level of redundancy is disproportionately packed into few FEs, a pattern termed functional over-redundancy (FOR). For instance, the most speciose FE in the Central Indo-Pacific contains 222 species (out of 3,689) whereas 38% of FEs (180 out of 468) have no functional insurance with only one species. Surprisingly, the level of FOR is consistent across the six fish faunas, meaning that, whatever the richness, over a third of the species may still be in overrepresented FEs whereas more than one third of the FEs are left without insurance, these levels all being significantly higher than expected by chance. Thus, our study shows that, even in high-diversity systems, such as tropical reefs, functional diversity remains highly vulnerable to species loss. Although further investigations are needed to specifically address the influence of redundant vs. vulnerable FEs on ecosystem functioning, our results suggest that the promised benefits from tropical biodiversity may not be as strong as previously thought

Coral reefs of Réunion Island in 2007 : status report and monitoring network

Réunion Island is 2500 km2 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 "bas"). 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 km2 along 25 km of the west and south coasts of the island. In addition to the natural infl uence of climatic events (global change) coral reef ecosystems are impacted by direct and indirect infl uences of the increase of human population. Direct impacts are mainly due to human overfrequenting of reef flats and overfishing. Indirect impacts are due to urbanization and to industrial, agricultural and urban pollutions. The competence in marine environment is assumed by an administration (Direction Régionale 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, Étang-Salé, Saint-Pierre) and the data are gathered since 2001 by ecoguards of the association "Parc Marin de la Réunion", 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 Régional). Réunion 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 "Status of coral reefs of the world". At the same time another network involving stakeholders is built using the Reef Chek protocole. At the present time, coral reefs of Réunion Island are deteriorated. If the density of the targeted species of fi" sh 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 "Réserve Naturelle Nationale Marine" (35 km2 of marine protected area)La Réunion est une île de 2500 km2 qui fait partie des régions ultrapériphériques de l'Union Européenne. La population était de 774 600 habitants en 2004 avec 25 % localisés dans la partie ouest de l'île et 80 % dans la frange littorale (appelée communément "les bas"). L'index PIB par habitant est de 50 % de celui de l'UE (rapport PIB par habitant local/PIB moyen UE). Le taux de chômage était de 33 % en 2004. Les écosystèmes récifaux couvrent 12 km2 et s'étendent sur un linéaire côtier de 25 km dans l'ouest et le sud de l'île. Les écosystèmes coralliens subissent en plus des influences naturelles des événements climatiques (réchauffement), les impacts anthropiques directs et indirects liés à la croissance démographique. Les impacts directs sont liés majoritairement à la surfréquentation des platiers et à la surexploitation des ressources. Les impacts indirects sont liés à l'urbanisation et aux pollutions d'origine urbaine, industrielle et agricole. La compétence en matière d'environnement marin est assurée par un service de l'État (Direction Régionale de l'Environnement). Les recherches sur les récifs coralliens sont menées par des Instituts de recherche (Université et IRD) et des ONG. Le premier réseau d'observation des récifs coralliens a été mis en place en 1998 sur l'unité récifale de Saint-Gilles/La Saline. Depuis il a été étendu aux trois autres principales unités récifales (Saint-Leu, Étang-Salé, Saint-Pierre) et la récolte des données est assurée depuis 2001 par les écogardes de l'Association Parc Marin de la Réunion, en partenariat avec le laboratoire ECOMAR (Université). Les données sont stockées dans une base de données (COREMO) et sont traitées par l'ARVAM (Agence pour la Recherche et la Valorisation Marine). Le financement de l'opération est assuré conjointement par l'État et le Conseil Régional. La Réunion fait partie du noeud Sud-Ouest Océan Indien du Global Coral ReefMonitoring Network (GCRMN). Elle participe régulièrement à la rédaction du rapport "Status ofcoral reefs ofthe world" sur l'état de santé des récifs dans le monde. En parallèle au réseau scientifique se met en place un réseau selon le protocole ReefCheck. Les récifs de la Réunion se dégradent actuellement. Si la densité des espèces de poissons ciblées par l'échantillonnage n'a pas varié significativement depuis 1999, la couverture corallienne vivante, elle, a diminué sensiblement sur la moitié des 14 stations suivies, notamment après deux phénomènes importants de blanchissement survenus en 2003 et 2004. Les divers impacts négatifs liés aux activités humaines contribuent à fragiliser ces milieux et à diminuer leur capacité de résilience. Ils sont ainsi de moins en moins aptes à résister aux événements climatiques exceptionnels (cyclones, houles) et aux conséquences néfastes du réchauffement climatique (blanchissement corallien). Pour faire face à ces enjeux de développement durable, depuis février 2007, 75 % des unités récifales de l'île ont acquis le statut de Réserve Naturelle Nationale Marine (35 km2 d'espaces marins protégés)

Comparing the Protests of Undocumented Migrants Beyond Contexts: Collective Actions as Acts of Emancipation

In this article, we demonstrate that the collective actions of undocumented migrants possess similar symbolic dimensions, even if the contexts of their actions differ. We explain this finding by focusing on the power relations that undocumented migrants face. Given that they occupy a very specific position in society (i.e., they are neither included in nor completely excluded from citizenship), they experience similar forms of power relations vis-à-vis public authorities in different countries. We argue that this leads them to participate in collective actions as acts of emancipation. Our analysis illustrates this argument by comparing marches by undocumented migrants in three countries: France, Germany and Canada-Quebec. Through an in-depth analysis, we demonstrate that these marches redefine the legal order and politicize the presence of undocumented migrants in the public sphere. By highlighting the cognitive, emotional and relational dimensions of collective actions, we show that the symbolic dimension of these three marches relates to the empowerment, pride and solidarity of undocumented migrants

Climate warming, marine protected areas and the ocean-scale integrity of coral reef ecosystems

Coral reefs have emerged as one of the ecosystems most vulnerable to climate variation and change. While the contribution of a warming climate to the loss of live coral cover has been well documented across large spatial and temporal scales, the associated effects on fish have not. Here, we respond to recent and repeated calls to assess the importance of local management in conserving coral reefs in the context of global climate change. Such information is important, as coral reef fish assemblages are the most species dense vertebrate communities on earth, contributing critical ecosystem functions and providing crucial ecosystem services to human societies in tropical countries. Our assessment of the impacts of the 1998 mass bleaching event on coral cover, reef structural complexity, and reef associated fishes spans 7 countries, 66 sites and 26 degrees of latitude in the Indian Ocean. Using Bayesian meta-analysis we show that changes in the size structure, diversity and trophic composition of the reef fish community have followed coral declines. Although the ocean scale integrity of these coral reef ecosystems has been lost, it is positive to see the effects are spatially variable at multiple scales, with impacts and vulnerability affected by geography but not management regime. Existing no-take marine protected areas still support high biomass of fish, however they had no positive affect on the ecosystem response to large-scale disturbance. This suggests a need for future conservation and management efforts to identify and protect regional refugia, which should be integrated into existing management frameworks and combined with policies to improve system-wide resilience to climate variation and change

Analyse écorégionale marine de Nouvelle-Calédonie : atelier d'identification des aires de conservation prioritaires

Dans le cadre de l'initiative pour les récifs coralliens du Pacifique sud (CRISP), le WWF-France a souhaité développer un projet pour la protection des récifs et des lagons néo-calédoniens. L'atelier, qui s'est déroulé les 10 et 11 août à Nouméa, avait pour objectif de rassembler les scientifiques et les experts du lagon néocalédonien pour identifier, sur la base de leur connaissance experte, les zones les plus remarquables du lagon (richesse, endémisme, originalité des faunes et flores, espèces emblématiques, zones d'intérêt fonctionnel) sur lesquelles doivent porter en priorité les efforts de conservation. Il a permis d'identifier 20 aires prioritaires pour la conservation, parmi lesquelles 6 ont un intérêt mondial, 4 ont un intérêt sur le plan régional, les autres ayant un intérêt local