Biology subjects

Leprieur, F.

Publications and source records attributed to Leprieur, F..

6 recordsLinked to original sources

bioRxiv2025

Global gaps and priorities for shark and ray conservation: Integrating threat, function, and evolutionary distinctiveness

Elasmobranchs (sharks, rays, and skates) face unprecedented extinction risk, with over one-third of species threatened primarily by overfishing. While marine protected areas (MPAs) are essential tools to help safeguard marine ecosystems and the species that inhabit them, we lack a comprehensive understanding of how well elasmobranchs are protected globally. Here, we (1) evaluate the current level of protection for elasmobranchs, (2) employ CAPTAIN reinforcement learning algorithm to identify areas that optimise conservation based on species level of threat and their functional and evolutionary distinctiveness, and (3) examine conservation conflicts and opportunities by identifying areas where conservation priorities overlap with high and low fishing pressures. Our analysis revealed severe protection deficits, with elasmobranchs having on average only 3% of their range covered by no-take MPAs and 64% of species under-represented relative to random expectations. Areas that optimise conservation priorities consistently converged in Australian, Southeast Asia, the Indian Ocean, Atlantic Africa, European Atlantic coasts, the Caribbean, and South American Atlantic regions. However, areas of highest conservation priority often coincided with intensive fishing, particularly in East Asian seas, highlighting conservation conflicts requiring strategic management. Our results provide actionable insights for policymakers to optimise conservation strategies and maximise biodiversity retention. TeaserReinforcement learning identifies priority areas to expand ocean protection for unique and irreplaceable elasmobranchs.

ecology↗

bioRxiv2021

Species ecology explains the various spatial components of genetic diversity in tropical reef fishes

Intraspecific genetic diversity should be dependent on species ecology, but the influence of ecological traits on interspecific differences in genetic variation is yet to be explored. Generating sequenced data for 20 tropical reef fish species of the Western Indian Ocean, we investigate how species ecology influences genetic diversity patterns from local to regional scales. We distinguish between the , {beta} and{gamma} components of genetic diversity, which we subsequently link to six ecological traits. In contrast to what is expected by the neutral theory of molecular evolution, we find that the and{gamma} components of genetic diversity are negatively associated with species abundance, which can be explained by larger variance in reproductive success in large populations and/or higher introgression in less frequent species. Pelagic larval duration, an important dispersal trait in marine fishes, is found to be negatively related to genetic {beta} diversity, as expected by theory. We conclude that the neutral theory of molecular evolution may not be sufficient to explain genetic diversity in tropical reef fishes and that additional processes influence those relationships.

genetics↗

bioRxiv2020

Strong functional divergence of tropical reef fish assemblages along the global diversity gradient

Coral reefs are experiencing declines due to climate change and local human impacts. While at local scale biodiversity loss induces shifts in community structure, previous biogeographical analyses recorded consistent taxonomic structure of fish communities across global coral reefs. This suggest that regional communities represent a random subset of the global species and traits pool, whatever their species richness. Using distributional data on 3,586 fish species and latest advances in species distribution models we show that the global distribution of reef fishes is influenced by two major traits (body size and diet) and produces a strong divergence in the trait structure of assemblages across the biodiversity gradient. This divergence is best explained by the isolation of reefs during past unfavorable climatic conditions and highlights the risk of a global community re-organization if the ongoing climate-induced reef fragmentation is not halted.

ecology↗

bioRxiv2020

Functionally unique, specialised, and endangered (FUSE) species: towards integrated metrics for the conservation prioritisation toolbox

Identifying species with disproportionate contributions to biodiversity can lead to effective conservation prioritisation. Despite well-established methods for identifying endangered species adding inordinately to evolutionary diversity, in this context functional diversity has been overlooked. Here, we compare different metrics designed to identify threatened species that contribute strongly to functional diversity. We use the diverse and threatened global marine megafauna as a case study. We found that functional contributions of species are not fully captured in a single metric. Although we found a very strong correlation between functional specialisation and distinctiveness, functional uniqueness was only moderately correlated with the other two metrics and identified a different set of top-10 species. These functional contributions were then integrated and combined with extinction risk to identify species that are both important contributors to functional diversity and endangered. For instance, the top-10 Functionally Unique Specialized and Endangered (FUSE) species contains three critically endangered, five endangered and two vulnerable species which - despite comprising only 3% of species - are among the top 10% most functionally unique and hold 15% of the global functional richness. The FUSE index was remarkably robust to different mathematical formulations. Combining one or more facets of a species contribution to functional diversity with endangerment, such as with the FUSE index, adds to the toolbox for conservation prioritisation. Nevertheless, we discuss how these new tools must be handled with care alongside other metrics and information.

ecology↗

bioRxiv2018

Global biogeographical regions of freshwater fishes

AimTo define the major biogeographical regions and transition zones for freshwater fish species.\n\nTaxonStrictly freshwater species of actinopterygian fish (i.e., excluding marine and amphidromous fish families).\n\nMethodsWe based our bioregionalisation on a global database of freshwater fish species occurrences in drainage basins, which, after filtering, includes 11 295 species in 2 581 basins. On the basis of this dataset, we generated a bipartite (basin-species) network upon which we applied a hierarchical clustering algorithm (the Map Equation) to detect regions. We tested the robustness of regions with a sensitivity analysis. We identified transition zones between major regions with the participation coefficient, indicating the degree to which a basin has species from multiple regions.\n\nResultsOur bioregionalisation scheme showed two major supercontinental regions (Old World and New World, 50% species of the world and 99.96% endemics each). Nested within these two supercontinental regions lie six major regions (Nearctic, Neotropical, Palearctic, Ethiopian, Sino-Oriental and Australian) with extremely high degrees of endemism (above 96% except for the Palearctic). Transition zones between regions were of limited extent compared to other groups of organisms. We identified numerous subregions with high diversity and endemism in tropical areas (e.g. Neotropical), and a few large subregions with low diversity and endemism at high latitudes (e.g. Palearctic).\n\nMain conclusionsOur results suggest that regions of freshwater fish species were shaped by events of vicariance and geodispersal which were similar to other groups, but with freshwater-specific processes of isolation that led to extremely high degrees of endemism (far exceeding endemism rates of other continental vertebrates), specific boundary locations, and limited extents of transition zones. The identified bioregions and transition zones of freshwater fish species reflect the strong isolation of freshwater fish faunas for the past 10 to 20 million years. The extremely high endemism and diversity of freshwater fish fauna raises many questions about the biogeographical consequences of current introductions and extinctions.

ecology↗

bioRxiv2018

Is phylogenetic diversity a surrogate for functional diversity across clades and space?

In the face of the biodiversity crisis, it is argued that we should prioritize species in order to capture high functional diversity (FD). Because species traits often reflect shared evolutionary history, many researchers have advocated for a \"phylogenetic gambit\": maximizing phylogenetic diversity (PD) should indirectly capture FD. For the first time, we empirically test this gambit using data from >15,000 vertebrate species and ecologically-relevant traits. Maximizing PD results in an average gain of 18% of FD relative to random choice. However, this average gain hides the fact that in over 1/3 of the comparisons, maximum PD sets contain less FD than randomly chosen sets of species. These results suggest that, while maximizing PD protection can help to protect FD, it represents a risky strategy.\n\nStatement of authorshipFM, MP, MC, SD, GVDR, RG, AOM, CT and WP conceived the design of the study. FM and GVDR conducted the analysis. FM, RG, MP and WP interpreted the results and wrote the first draft of the manuscript. All authors edited the final version.\n\nData accessibility statementMost of the data is publicly available (see methods). The Fish data is available upon request.\n\nCode accessibility statementR functions developed in this paper are available at https://github.com/FloMazel/FD_PD_Max

ecology↗