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Les articles de Samuel Hilaire
de Miguel Cabrera-Brufau, Camille Minaudo, Katrin Attermeyer, Alba Camacho-Santamans, Rafael Carballeira, Benjamin Misteli, Jorge Montes-Pérez, Daniel Morant, Biel Obrador, Antonio Picazo, et al.
In Ecological Engineering, 232 (November, 2026), 108080
En ligne : www.sciencedirect.com[...]
Coastal wetlands play a substantial role in regulating Earth's climate through exchanges of greenhouse gases (GHGs). Current European policies promote widespread coastal wetland restoration to reverse historical losses and ongoing pressures. However, substantial uncertainty remains regarding how carbon dioxide (CO2) and methane (CH4) fluxes respond to restoration across different coastal wetland types and whether these responses translate into net climate mitigation in terms of CO2 equivalents (CO2-eq). We measured simultaneous CO2 and CH4 fluxes using static chambers across four seasons at multiple locations spanning preserved, altered and restored sites within six European coastal wetlands of different ecological types. By comparing GHG exchanges and resulting CO2-eq balances across wetlands, we identified dominant biogeochemical drivers of CO2 and CH4 dynamics and assessed the climate mitigation potential of conservation and restoration actions. CO2 fluxes were primarily controlled by landscape-scale vegetation cover and inundation, whereas CH4 emissions responded to less evident changes in water quality, salinity and wetland hydrodynamics. Comparisons of CO2-eq balances between altered and restored sites showed that seagrass replantation was associated with significant mitigation potential under both 100-year and 20-year CH4 warming scenarios, while eutrophication reversal through improved water treatment was only significant under the 20-year scenario. In contrast, other restoration measures modified CO2 and CH4 fluxes in opposing directions, resulting in no significant net change in combined CO2-eq balances. Overall, our results demonstrate that climatic responses to coastal wetland restoration are both GHG-specific and wetland-type dependent, underscoring the need for tailored restoration strategies and robust, multi-GHG monitoring to detect and accurately quantify potential climatic benefits.
de Bruna R. F. Oliveira, Antonio Camacho, Anis Guelmami, Christoph Schröder, Nina Bègue, Martynas Bucas, Constantin Cazacu, Elisa Ciravegna, João Pedro Coelho, Relu Giuca Constantin, et al.
In Environmental Science & Policy, 179 (May, 2026), 104386
En ligne : www.sciencedirect.com[...]
Ecosystem restoration is a paramount policy priority for this decade, with ambitious global and European targets requiring unprecedented levels of data-driven implementation. Achieving effective and equitable restoration, particularly for coastal wetlands, hinges on spatially explicit socio-ecological information - maps that integrate habitats, ecosystem services, human activities, and pressures to guide prioritization, stakeholder negotiation, and adaptive management. This study, grounded in the RESTORE4Cs initiative, introduces an innovative multi-layered dataset that bridges science and policy for six emblematic European coastal wetlands: Ria de Aveiro (Portugal), Valencian Wetlands (Spain), Camargue (France), Southwest Dutch Delta (Netherlands), Curonian Lagoon (Lithuania), and the Danube Delta (Romania). The dataset consolidates ecological mapping (EUNIS 2021, 2022), human activity and pressure documentation (aligned with EU Habitats Directive, Water Framework Directive, Marine Strategy Framework Directive), comprehensive ecosystem services mapping (CICES v5.1), alongside robust participatory community and stakeholder data. Altogether, the database encapsulates 97 habitat records, 23,160 activity-pressure associations, and 1,668 ecosystem service records—enabling robust cross-regional analyses and direct integration into evidence-based decision support tools. By illustrating practical pathways for participatory engagement, trade-off negotiation, and cross-scale integration, this research equips scientists, policymakers, practitioners, and communities with the scientific foundation to propel the Nature Restoration Regulation and Biodiversity Strategy 2030 objectives, fortifying Europe’s climate adaptation trajectory. The approach showcased signals a new era for restoration science – where spatially explicit, multi-actor data supports policy, mobilizes citizen stewardship, and accelerates the transformative ambitions of Europe’s restoration decade.
de Maite Martínez-Eixarch, Pere Masqué, Anna Lafratta, Paul Lavery, Samuel Hilaire, Lluís Jornet, Cyrille Thomas, Arnaud Boisnard, Néstor Pérez-Méndez, Carles Alcaraz, et al.
In Science of The Total Environment, 950 (November, 2024), 175224
En ligne : www.sciencedirect.com[...]
Coastal wetlands are crucial in climate change regulation due to their capacity to act as either sinks or sources of carbon, resulting from the balance between greenhouse gas (GHG) emissions, mainly methane (CH4), and soil carbon sequestration. Despite the paramount role of wetlands in climate regulation few studies investigate both aspects. The Camargue is one of the largest wetlands in Europe, yet the ways in which environmental and anthropic factors drive carbon dynamics remain poorly studied. We examined GHG emissions and soil organic carbon (SOC) stocks and accumulation rates in twelve representative wetlands, including two rice fields, to gain insights into the carbon dynamics and how it is influenced by hydrology and salinity. Mean CH4 rates ranged between – 87.0 and 131.0 mg m−2 h−1and the main drivers were water conductivity and redox, water table depth and soil temperature. High emission rates were restricted to freshwater conditions during summer flooding periods whereas they were low in wetlands subjected to summer drought and water conductivity higher than 10 mS cm−1. Nitrous oxide emissions were low, ranging from – 0.5 to 0.9 mg N2O m−2 h−1. The SOC stocks in the upper meter ranged from 17 to 90 Mg OC ha−1. Our research highlights the critical role of low-saline wetlands in carbon budgeting which potentially are large sources of CH4 but also contain the largest SOC stocks in the Camargue. Natural hydroperiods, involving summer drought, can maintain them as carbon sinks, but altered hydrology can transform them into sources. Artificial freshwater supply during summer leads to substantial CH4 emissions, offsetting their SOC accumulation rates. In conclusion, we advocate for readjusting the altered hydrology in marshes and for the search of management compromises to ensure the compatibility of economic and leisure activities with the preservation of the inherent climate-regulating capacity of coastal wetlands.
de Brigitte Poulin, Gaëtan Lefebvre, Samuel Hilaire, Laurence Després
In Ecotoxicology and Environmental Safety, 243 (September, 2022), 10
En ligne : linkinghub.elsevier.com[...]
Bacillus thuringiensis subsp. israelensis (Bti) is the main larvicide used to control mosquitoes worldwide. Although there is accumulating evidence of Bti having environmental effects on non-target fauna, relatively few field studies have documented the fate of Bti spores in the environment. Spore density was quantified over a 6-yr period (2012–2017) in Mediterranean marshes sprayed with Vectobac 12AS (32 ITU/ha) since 2006 to reduce the nuisance caused by Aedes caspius. Bti spores were naturally found in all habitat types. Spore density expressed as colony-forming units per gram of soil (CFU g− 1) increased significantly at treated sites by a factor of 22 to 500 times relative to control sites, with mean values of 7730 CFU g− 1 in halophilous scrubs, 38,000 in reed beds, 49,000 in bulrush beds and 50 000 in rush beds. Spore density varied little in the first months after the spraying season (April-October), but increased sharply in spring, just before the annual launch of mosquito control. Considering that Bti is an insect pathogen that cannot proliferate without a suitable insect host, this unexpected recrudescence in spring could be related to the warming of water that triggers activity and development of benthic organisms such as chironomids, which may contribute to Bti proliferation by ingesting accumulated spores at the surface of sediments. While spore density tends to decrease over time, presumably during the summer period as a result of increased UV exposure, three to four years were necessary for spore density to return to normal levels after mosquito-control interruption. This study is important because it demonstrates that environmental effects of mosquito-control using Bti can far exceed the short period of Bti efficacy against lentic mosquitoes. Considering that Bti is a microbial agent, these long-term effects should be addressed at multiple levels of ecosystem organization from a one-health perspective.
de Pierre Mallet, Arnaud Béchet, Thomas Galewski, François Mesléard, Samuel Hilaire, Gaëtan Lefebvre, Brigitte Poulin, Clelia Sirami
2022, 8
En ligne : www.sciencedirect.com[...]
Increase in pesticide use and landscape homogenization are two key drivers of the decline in farmland biodiversity. The effects of these two drivers are often complex, interactive and vary among taxonomic groups. Our study tested the hypothesis that pesticide use influences the effect of different components of landscape complexity on different taxonomic groups. We sampled 32 rice paddy landscapes of 1 * 1 km in the Camargue (south of France), a wetland internationally recognized as an exceptional biodiversity hotspot. We assessed the abundance and diversity of 7 taxa (plants, bees, butterflies, hoverflies, carabids, spiders and birds) in 3 or 4 crop fields per landscape. For each landscape, we measured the length of different field margins (ditch, grass strip, hedgerow), the proportion of semi-natural areas and crop diversity. For each field, we measured management intensity by the treatment frequency index (TFI) of pesticides. We then tested our hypothesis across 118 fields. Our results show that different components of landscape complexity influence different taxonomic groups: crop diversity and the length of ditches influence bee abundance and species richness, the proportion of semi-natural areas influence spider abundance and species richness, and the length of grass strips influences bird abundance. Moreover, we show that local pesticide use modulates these effects, with more positive effects of landscape complexity in intensively-managed fields. However, we found no interactive effect between landscape complexity and field management for plants, butterflies, hoverflies and carabids. Our study therefore suggests that different components of landscape complexity need to be maintained in order to preserve multiple taxonomic groups. Moreover, it suggests that increasing landscape complexity is particularly relevant to restore biodiversity in intensively-managed fields. Agricultural policies should therefore support the simultaneous increase in semi-natural areas, field margins length and crop diversity to conserve a wide range of taxonomic groups in intensively-managed rice paddy landscapes.The Settlement of Glossy Ibis in France
de Jocelyn Champagnon, Yves Kayser, Jérémiah Petit, Loïc Marion, Sebastien Reeber, Thomas Blanchon, Samuel Hilaire, Irene Badone, Pierre Crouzier, Regis Purenne, et al.
In SIS Conservation, 1 (December, 2019), 50-55
En ligne : storkibisspoonbill.org[...]
The Glossy Ibis Plegadis falcinellus was very rarely breeding in France until its settlement in Camargue in 2006, in a colony of ardeids. From then, the number of breeding pairs increased exponentially to reach 2,087 breeding pairs in 2017 distributed over ten colonies mainly in Camargue but also in others sites over the French Mediterranean coast. In parallel, breeding attempts occurred regularly in other regions, with some successes in Loire Atlantic on the Atlantic coast. Here we present some preliminary results on the ringing programme of chicks conducted in Camargue since 2006 and on the diet of the breeding birds. Finally, we discuss factors that influence the settlement of new colonies.Increasing crop heterogeneity enhances multitrophic diversity across agricultural regions
de Clelia Sirami, Nicolas Gross, Aliette Bosem Baillod, Colette Bertrand, Romain Carrié, Annika Hass, Laura Henckel, Paul Miguet, Carole Vuillot, Audrey Alignier, et al.
In Proceedings of the National Academy of Sciences, 116(33) (2019-08-13), 16442-16447
En ligne : www.pnas.org[...]
Agricultural landscape homogenization has detrimental effects on biodiversity and key ecosystem services. Increasing agricultural landscape heterogeneity by increasing seminatural cover can help to mitigate biodiversity loss. However, the amount of seminatural cover is generally low and difficult to increase in many intensively managed agricultural landscapes. We hypothesized that increasing the heterogeneity of the crop mosaic itself (hereafter “crop heterogeneity”) can also have positive effects on biodiversity. In 8 contrasting regions of Europe and North America, we selected 435 landscapes along independent gradients of crop diversity and mean field size. Within each landscape, we selected 3 sampling sites in 1, 2, or 3 crop types. We sampled 7 taxa (plants, bees, butterflies, hoverflies, carabids, spiders, and birds) and calculated a synthetic index of multitrophic diversity at the landscape level. Increasing crop heterogeneity was more beneficial for multitrophic diversity than increasing seminatural cover. For instance, the effect of decreasing mean field size from 5 to 2.8 ha was as strong as the effect of increasing seminatural cover from 0.5 to 11%. Decreasing mean field size benefited multitrophic diversity even in the absence of seminatural vegetation between fields. Increasing the number of crop types sampled had a positive effect on landscape-level multitrophic diversity. However, the effect of increasing crop diversity in the landscape surrounding fields sampled depended on the amount of seminatural cover. Our study provides large-scale, multitrophic, cross-regional evidence that increasing crop heterogeneity can be an effective way to increase biodiversity in agricultural landscapes without taking land out of agricultural production. / Cet article est issu du projet Farmland (2011-2015) financé par Biodiversa et réalisé sur 7 sites Européens dont la Camargue. Cette étude s’appuie sur deux saisons intensives de terrain pour échantillonner les plantes, insectes et oiseaux sur les parcelles agricoles. Ces données, combinées à une numérisation précise du paysage sur SIG, ont permis de démontrer qu’il était possible d’augmenter la biodiversité et les services qu’elle rend aux agriculteurs (pollinisation, contrôle des ravageurs) en diversifiant le nombre de cultures et en réduisant la taille des parcelles, sans nécessairement diminuer la surface agricole utile.
Mosquito Traps: An Innovative, Environmentally Friendly Technique to Control Mosquitoes
de Brigitte Poulin, Gaëtan Lefebvre, Camille Muranyi-Kovacs, Samuel Hilaire
In International Journal of Environmental Research and Public Health, 14(3) (2017-03-18), 313
En ligne : www.mdpi.com[...]
We tested the use of mosquito traps as an alternative to spraying insecticide in Camargue (France) following the significant impacts observed on the non-target fauna through Bti persistence and trophic perturbations. In a village of 600 inhabitants, 16 Techno Bam traps emitting CO2 and using octenol lures were set from April to November 2016. Trap performance was estimated at 70% overall based on mosquitoes landing on human bait in areas with and without traps. The reduction of Ochlerotatus caspius and Oc. detritus, the two species targeted by Bti spraying, was, respectively, 74% and 98%. Traps were less efficient against Anopheles hyrcanus (46%), which was more attracted by lactic acid than octenol lures based on previous tests. Nearly 300,000 mosquitoes from nine species were captured, with large variations among traps, emphasizing that trap performance is also influenced by surrounding factors. Environmental impact, based on the proportion of non-target insects captured, was mostly limited to small chironomids attracted by street lights. The breeding success of a house martin colony was not significantly affected by trap use, in contrast to Bti spraying. Our experiment confirms that the deployment of mosquito traps can offer a cost-effective alternative to Bti spraying for protecting local populations from mosquito nuisance in sensitive natural areas.Egg hatching phenology and success of Lestes macrostigma in two temporary brackish ponds
de Philippe Lambret, Samuel Hilaire, Robby Stoks
In International Journal of Odonatology (2017), 1–12
En ligne : www.tandfonline.com[...]
Although a full life cycle approach is optimally needed to make conservation decisions, the egg stage is often neglected for insect species of special conservation interest. Water management and related abiotic
factors are relevant factors to consider in aquatic species. Lestes macrostigma is a threatened damselfly restricted to temporary brackish waters. Here we provide detailed information on its hatching success and
phenology in two natural field populations. Shoots containing fresh egg clutches of L. macrostigma were sampled in late June, just after the oviposition period. In the fall, shoots were separately placed in plastic
boxes in two ponds in southern France. Examination of eggs indicated L. macrostigma overwinters at an early embryonic stage. The following spring we monitored hatching in detail. Hatching began on 15 March in both ponds and ended on 27 April. Hatching was synchronized, with half of the eggs hatching within five days in the first pond and 14 days in the second pond. Lower water temperatures decreased hatching success and likely also delayed hatching. Embedment of shoots in ice increased egg mortality.
Based on our data, wildlife managers are encouraged to maintain water levels high during winter to reduce the risk of freezing of L. macrostigma eggs.
de Héctor Rodríguez-pérez, Samuel Hilaire, François Mesléard
In Hydrobiologia, 767(1) (March 2016), 333-345
En ligne : link.springer.com[...]
Temporary ponds, acknowledged for their conservation value, are colonized by the invasive crayfish Procambarus clarkii. We have tested the consequences of this colonization for the ecosystem under two contrasted scenarios: one single individual arrival or three individuals arrival. We recreated the temporary pond ecosystem in 1 m2 tanks to investigate the impact of the two crayfish densities. We studied the macrophyte community composition and abundance, chlorophyll a and total suspended solids concentrations, and the diversity and functional composition of micro-crustacean and macro-invertebrate communities. We observed a reduction of macrophyte biomass in experimental crayfish mesocosms in comparison with control tanks, nearly 80 and 40% less in 3 and 1 crayfish/m2 tanks, respectively. The macrophyte community shifted, followed by a filamentous algae development, an increase of bare sediment and turbidity in crayfish tanks. The macro-invertebrate community suffered a richness loss of 28 and 22%, in 3 and 1 crayfish/m2 tanks, respectively. Functionally, macro-invertebrate diversity reduction most strongly affected the grazer, detritivore and predator trophic groups. Microcrustaceans seemed not to be affected by the introduction of the crayfish. The introduction of the crayfish greatly altered the ecosystem structure and subsequently the ecosystem functioning.
de E. Meineri, H. Rodriguez-perez, Samuel Hilaire, François Mesléard
2013
de H. Rodriguez-perez, H. Cayuela, Samuel Hilaire, Anthony Olivier, François Mesléard
2013Recensement des chevêches d'Athéna Athene noctua dans la plaine du Trébon (Bouches-du-Rhône) (2008)
de N. Vincent-martin, Antoine Arnaud, Samuel Hilaire
2008
