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Legras, Gaëlle; Loiseau, Nicolas; Gaertner, Jean-claude; Poggiale, Jean-christophe; Lenco, Dino; Mazouni, Nabila; Mérigot, Bastien. |
Describing how communities change over space and time is crucial to better understand and predict the functioning of ecosystems. We propose a new methodological framework, based on network theory and modularity concept, to determine which type of mechanisms (i.e. deterministic versus stochastic processes) has the strongest influence on structuring communities. This framework is based on the computation and comparison of two networks: the co-occurrence (based on species abundances) and the functional networks (based on the species traits values). In this way we can assess whether the species belonging to a given functional group also belong to the same co-occurrence group. We adapted the Dg index of Gauzens et al. (2015) to analyze congruence between both... |
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Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00599/71142/69458.pdf |
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Olivier, Damien; Loiseau, Nicolas; Petatan-ramirez, David; Trujillo Milian, Oscar; Suarez-castillo, Alvin N.; Torre, Jorge; Munguia-vega, Adrian; Reyes-bonilla, Hector. |
The Gulf of California (GC) is a semi-closed sea in the Tropical Eastern Pacific and is recognised as a highly diverse marine ecosystem. Despite this status, this region is still poorly studied in comparison to other marine hotspots. To start filling this gap, we attempt to provide a global overview of reef-fish diversity around the numerous islands of the region. We evaluated species richness, the abundance and biomass, and the functional diversity of the fish assemblages for the major islands of the GC. We first highlight that the southwestern part of the central GC is the hotspot of reef-fishes diversity within the GC, in terms of species richness, functional diversity, and fish abundance. We then found out an important functional divergence between... |
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Palavras-chave: Biodiversity; Biologically important area; Functional traits; Marine protected area; Sea of Cortez; Tropical Eastern Pacific. |
Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00476/58786/62421.pdf |
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Legras, G.; Loiseau, Nicolas; Gaertner, Jean-claude. |
Functional richness, currently defined as the amount of niche space occupied by the species within a community, is one of the three major components of functional diversity. Different indices have been developed in order to quantify this component. However, the range of indices available for assessing functional richness, often mathematically complex and based on different rationales, can cause confusion for field ecologists and lead to misinterpretation of the results obtained. In this context, we have provided the first study exclusively focused on the comparison of the definitions, advantages and drawbacks of a large set of functional richness indices. The first part of this work is focused on four indices (FDP&G, FRic, TOP and N-hypervolumes... |
Tipo: Text |
Palavras-chave: Functional richness indices; Index properties; Limitations; Guidelines. |
Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00435/54666/59606.pdf |
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Lagabrielle, Erwann; Allibert, Agathe; Kiszka, Jeremy J.; Loiseau, Nicolas; Kilfoil, James P.; Lemahieu, Anne. |
Understanding the environmental drivers of interactions between predators and humans is critical for public safety and management purposes. In the marine environment, this issue is exemplified by shark-human interactions. The annual shark bite incidence rate (SBIR) in La Réunion (Indian Ocean) is among the highest in the world (up to 1 event per 24,000 hours of surfing) and has experienced a 23-fold increase over the 2005–2016 period. Since 1988, 86% of shark bite events on ocean-users involved surfers off the leeward coast, where 96% of surfing activities took place. We modeled the SBIR as a function of environmental variables, including benthic substrate, sea temperature and period of day. The SBIR peaked in winter, during the afternoon and dramatically... |
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Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00429/54011/55227.pdf |
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Tessier, Emmanuel; Pothin, Karine; Chabanet, Pascale; Fleury, Pierre-gildas; Bissery, Claire; David, Gilbert; Thomassin, Aurélie; Lemoigne, Valerie; Loiseau, Nicolas. |
The objectives of marine protected areas (MPA), such as Reunion’s Marine Reserve founded in 2007, are (i) protect habitats (ecosystems) and resources (biodiversity) from increasing pressure due to a major urban, economic and recreational development; ii) manage uses and conflicts between traditional fisheries, spear-fishing, diving and recreational activities inside the coastal zone. These goals necessitate monitoring tools such as indicators and diagnostics. The PAMPA programme involves seven MPA including the Natural Marine Reserve of La Reunion (RNMR). It aims for each site to identify and validate indicators according to management objectives and group them in a MPA performance dashboard. This panel will help to visualize temporal trends and define... |
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Palavras-chave: Aires Marines Protégées; RNMR de La Réunion; Ressources; Usages; Gouvernance; Indicateurs de performance; Tableau de bord; Marine Protected Area; Reunion Natural Marine Reserve; Resources; Uses; Gouvernance; Performance indicators; Dashboard. |
Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00050/16161/13644.pdf |
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