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Les articles de Philippe Lambret
de Charlotte Theys, Julie Verheyen, Nedim Tüzün, Lizanne Janssens, Philippe Lambret, Luc De Meester, Ellen Decaestecker, Robby Stoks
In Oikos, (en ligne) (October, 2026), e12515
En ligne : onlinelibrary.wiley.com[...]
Triggered by global warming there is increasing interest in understanding why conspecific populations differentiate along latitudinal gradients. Although microbiomes may shape host traits and vary geographically, how hosts differentially assemble microbiomes across latitudes and how this shapes latitudinal patterns in host trait values has been understudied. This is especially true for organisms with complex life cycles, where metamorphosis may reset the microbiome. We examined microbiome composition along a latitudinal gradient and assessed the relative influence of host and environment in shaping the microbiome of the damselfly Ischnura elegans. We sampled bacterioplankton from high-latitude (southern Sweden) and low-latitude (southern France) ponds, along with larval gut and adult abdominal microbiomes from I. elegans inhabiting these ponds. Additionally, we conducted a reciprocal translocation experiment in which larvae with a strongly depleted gut microbiome were transferred between three high- and three low-latitude ponds, allowing microbiome reassembly from the local bacterioplankton, and quantified the growth rate of the larvae. We found latitudinal differences in bacterioplankton and host-associated microbiomes in adults and to a lesser extent in larvae, highlighting differences in microbiome composition across the latitudinal gradient and suggesting strong environmental effects on microbiome reassembly. Moreover, despite these differences, larvae and adults shared a small proportion of their microbiome (ca 15.83%). The reciprocal translocation experiment revealed that microbiome reassembly in microbiome-depleted larvae was primarily shaped by the local environment, rather than the host source population or latitude, underscoring the strong influence of environmental filtering in shaping microbiome composition. Moreover, phenotypic differences in larval growth rate between high- and low-latitude populations disappeared after the seven-day translocation, suggesting that local environmental conditions overruled any underlying genetic differentiation. By combining microbiome sampling across latitudes with a novel reciprocal translocation approach using microbiome-depleted larvae, our study provides key insights into how the environment shapes host–microbiome associations along geographic gradients.
de Philippe Lambret
In Martinia, 40(4) (Avril, 2026), 21-36
En ligne : martinia.insectes.org[...]
Method for the monitoring of Lestes macrostigma (Eversmann, 1836) populations: a trade-off between level of information and effort invested (Odonata: Lestidae). Lestes macrostigma (Eversmann, 1836) is threatened at the French and European Union scales, and as such should be included in the Habitats Directive. This species is integrated into the French National Action Plan for dragonflies and implementing its national monitoring is a priority action. We present here a method offering trade-off between gathered information and invested effort. This method focuses on the autochthony of the studied population and aims to estimate the total number of imagos emerging from a breeding site. To do so, the site is surveyed along a walk determined by the operator and imagos are counted over a width of 3 m, distinguishing the tenerals which are used as a proxy for evidence of autochthony. This count is then extrapolated to the site scale considering the area of habitat favourable to the species oviposition and emergence, and finally over the season in order to assess the minimal size of the autochthonous population. This size is expressed in classes on an exponential scale: 0 – no individual; 99 – tens of individuals; 999 – hundreds of individuals; 9999 – thousands of individuals, etc. To allow analysis at different scales, we argue that this specific monitoring should be mutualised with a general dragonfly monitoring scheme, such as the French “Steli”, at least at one of the monitored stations.Wetlands and dragonflies under threat in the Gediz delta, Türkiye
de Philippe Lambret, Şafak Arslan, Lisa Ernoul, Anthony Olivier, Serdar Özuslu, Çağdaş Yaşar, Özge Yaylalı
In Dragonfly Conservation Europe Newsletter, (en ligne) (August,2025), 12-14
En ligne : www.gbif.org[...]
The Gediz delta covers ca. 400 km², most of which is occupied by agricultural crops (mainly cereals and cotton). Despite the designation of large portions of the delta as protected areas, many pressures continue to threaten the ecologically sensitive zones. Pressures such as urban expansion, water over-abstraction, intensive grazing, spread of invasive plant species, and unsustainable agricultural practices are accentuated by the lack of integrated management and enforcement of policies. In addition, the dominant wind direction and geographical position of the delta contribute to the transport of anthropogenic pollution into the area. Pesticides and fertilizers from surrounding agricultural lands, further degrades the quality of wetlands. Irrigation needs have intensified during the last decades, resulting in illegal damming and an increase in pumping water from the Gediz River. As a result, the freshwater inflows feeding the remaining natural habitats have dramatically decreased, leading to the salinization of many wetlands. This reduction in freshwater input has also led to habitat fragmentation, further isolating temporary wetland patches and negatively affecting species dispersal and ecosystem connectivity. In addition, recent changes in the hydraulic management of some protected areas of the delta have changed some wetlands into pasturelands. Although grazing pressure in the delta has not been quantified, field observations indicate that livestock —particularly cattle and sheep— enter the ponds and disturb the vegetation along the banks. This practice is likely to have negative impacts on dragonfly larvae, especially with the reduction of plant shoots that the larvae need for metamorphosis. Given that dragonflies are often used as bioindicators, their decline may reflect broader ecosystem degradation throughout the delta.Status of Lestes macrostigma in Bulgaria
de Philippe Lambret, Stanimira Deleva, Spas Uzunov, Dimitar Popov
In Odonatologica, 54(1/2) (2025), 53-84
Measuring population trends of freshwater insects helps to assess their conservation status and to design management protocols for wetlands. Lestes macrostigma is restricted to temporary brackish waters, a limited and fragmented habitat. Throughout its range this species is threatened at different levels, and, in Bulgaria, it has been assessed as “Critically Endangered”. In the past, along the Black Sea coast, it was known to be abundant and reproducing at two sites: Shablenska Tuzla Lake and Poda Protected Area. At a third site, Pomorie Lake, only a few individuals were recorded without clear evidence of reproduction. We aimed at updating its distribution along the Bulgarian Black Sea coast and determining the conservation status of its populations by conducting surveys from 2021 to 2024 at 53 localities, mainly within coastal lagoons and estuaries. We recorded all Odonata species along with their various life stages and reproductive behaviour. Other resident species recorded in association with L. macrostigma were Lestes barbarus, L. dryas, Ischnura elegans, Aeshna affinis, Sympetrum fonscolombii, S. meridionale, and S. striolatum. We counted L. macrostigma adults along walks and extrapolated abundance over the entire sites and season. Lestes macrostigma population size reached hundreds of thousands of adults at Shablenska tuzla and Pomorie Lake. At Nanevska tuzla and Atanasovsko Lake, two new sites for the species, thousands of adults were present. However, we found that L. macrostigma had disappeared from at least a part of Poda Protected Area, most likely because of a change in water management practices. As the timing of the flooding period is a key feature of the species’ habitat, we found that its presence in the temperate Bulgarian estuaries was unlikely. As conservation management plans are still lacking for Shablenska tuzla and Pomorie Lake, the future of the two largest L. macrostigma populations of Bulgaria of international importance seems tenuous and uncertain. Therefore, key actions for the conservation of L. macrostigma are the proper management of its existing reproductive sites and restoring or recreating temporary wetlands.Conservation ecology of the threatened damselfly Lestes macrostigma (2024)
de Philippe Lambret
Louvain : Katholieke Universiteit Leuven, 2024, 202
Les insectes constituent le groupe d’espèces déclinant le plus rapidement et sont parmi les plus menacés par les activités humaines. Malgré cela, ils sont largement négligés par les politiques de conservation et la recherche en biologie de la conservation. Les zones humides ont fortement disparu durant le dernier siècle et demeurent à ce jour menacées, ce qui impacte tous les groupes taxonomiques de la biodiversité, dont les insectes. Les odonates (les demoiselles et les libellules) sont de bons indicateurs de l’état de conservation des zones humides. La restauration d’habitats (recréation incluse) a été érigée comme une stratégie prioritaire durant la décennie en cours. De telles actions de conservation sont facilitées par l’usage d’une espèce étendard ; mais pour être efficaces, une connaissance solide de leurs exigences écologiques est nécessaire. Cette thèse de doctorat s’est focalisée sur la demoiselle menacée Lestes macrostigma, en tant qu’espèce étendard pour la conservation et la restauration des mares temporaires saumâtres. Les connaissances étaient lacunaires quant à l’influence du régime hydrologique et du niveau de salinité de l’eau sur les œufs et les larves, qui sont pourtant des stades clés de la dynamique des populations d’odonates. Dans le but d’entreprendre des actions de conservation basée sur des preuves, nous avons taché de combler ces lacunes en menant quatre études en Camargue, dans le sud de la France. Cette zone géographique se caractérise par des dépôts de sel et un climat méditerranéen, qui favorise l’apparition de zones humides temporaires et saumâtres abritant des populations reproductrices de L. macrostigma.
Afin d’améliorer notre connaissance de la biologie de l’œuf, nous avons étudié le développement embryonnaire ainsi que la phénologie et le succès d’éclosion dans deux mares temporaires saumâtres. Nous avons trouvé que les œufs – pondus dans des tiges de plantes durant le printemps précédent – restent à un stade de développement embryonnaire précoce durant l’été, l’automne et l’hiver. Ceci augmente probablement leur résistance aux températures extrêmes et illustre l’adaptation de L. macrostigma aux milieux temporaires dont la temporalité de submersion est incertaine. Cependant, la prise dans la glace des tiges de plantes contenant les œufs diminue leur survie, suggérant que des niveaux d’eau plus hauts au-dessus des tiges réduirait la mortalité des œufs en les protégeant des plus basses températures hivernales. L’éclosion s’est étalée de mi-mars à mi-avril et a été très synchronisée. Les différences de phénologie entre les deux mares s’expliquent probablement par des différences de température de leurs eaux.
La salinité de l’eau est un facteur pilote majeur des communautés d’insectes. Aussi avons-nous étudié en conditions de laboratoire les effets des niveaux de salinité vécus durant les stades embryonnaire et larvaire. Nous n’avons pas trouvé d’effet de la concentration en sel de mer sur la survie des œufs (succès d’éclosion) dans la gamme 2–9.5 g/L. En revanche, la survie larvaire a augmenté avec le niveau de salinité entre 0,5 et 8 g/L mais a chuté à zéro à 16 g/L. Les niveaux de salinité croissants ont augmenté la durée de développement larvaire jusqu’à l’âge adulte, et ont diminué les taux de croissance ainsi que la taille des adultes à l’émergence. Le niveau de salinité vécu durant la phase larvaire n’a eu d’effet ni sur la masse de muscles thoraciques des adultes, ni sur leur aptitude au vol, ni sur leur investissement dans les fonctions immunitaires, ni sur l’énergie qui leur était disponible. Toutefois, la consommation énergétique des adultes a augmenté avec les niveaux de salinité, résultant en un bilan énergétique plus faible. Nos résultats ont donc indiqué que, par rapport à la salinité de l’eau, L. macrostigma est un généraliste (niche écologique fondamentale) dont la niche écologique réalisée s’est déplacée vers les eaux saumâtres.
D’autres facteurs, comme les interactions biologiques, vécues durant la phase larvaire peuvent avoir des effets sur les larves et se répercuter sur les adultes. Nous avons donc mené une étude de terrain sur 33 mares et marais, en évaluant l’effet de 14 variables biotiques et abiotiques sur l’abondance des larves de L. macrostigma et sur la taille des adultes à l’émergence. Nous avons trouvé que les larves étaient plus abondantes dans les mares de plus petite taille et dont les dates de submersion étaient plus tardives durant l’automne et l’hiver. Ceci semblait s’exprimer par les larves prédatrices de libellules de la famille des Aeshnidae, qui étaient plus grandes et plus abondantes dans les mares à submersion plus précoce. Une grande vulnérabilité des larves de L. macrostigma aux prédateurs pourrait être liée à un haut niveau d’activité, qui serait associé à une croissance rapide et un fort taux de développement qu’impose l’assèchement de leur habitat temporaire. En outre, les adultes de L. macrostigma ont eu tendance à être plus grands lorsqu’ils émergeaient de mares ayant de plus hauts niveaux d’eau, probablement du fait que les eaux plus froides allongent la période de développement larvaire. En revanche, nous n’avons trouvé aucun effet des niveaux de salinité ni de la disponibilité en plantes hôtes de ponte sur l’abondance des larves de L. macrostigma.
Afin d’évaluer si la préférence que montrent les adultes pour certains types de plantes lors de la ponte sont bénéfiques à leur progéniture, nous avons étudié en conditions semi-contrôlées les effets de la date de submersion des pontes et du type de plante dans lequel les œufs ont été pondus sur leur succès d’éclosion. Nous avons trouvé que la submersion des pontes est nécessaire à l’éclosion. Les œufs ont été capables de supporter – bien qu’avec un faible taux de survie – la sécheresse jusqu’au mois d’avril (c’est-à-dire 10 mois sans submersion), mais aucun œuf n’a pu éclore dans le cas d’une submersion plus tardive. Les œufs pondus dans le Scirpe maritime Bolboschoenus maritimus ont eu un taux de survie plus grand et un développement embryonnaire plus rapide. Puisque B. maritimus pousse dans des parties des mares plus profondes, et est par conséquent submergé plus tôt que les autres plantes hôtes de ponte, cela suggère que la préférence que montrent les adultes pour B. maritimus lors de la ponte est une réponse adaptative à l’incertitude des conditions de submersion de l’habitat typique de L. macrostigma.
Les résultats de ces études, qui intègrent les stades clés du cycle de vie de L. macrostigma, fournissent une base scientifique sur laquelle développer les actions de conservation visant non seulement l’espèce, mais aussi la restauration de mares méditerranéennes temporaires saumâtres en utilisant L. macrostigma comme espèce étendard. La mise en place d’une hydropériode s’étendant de novembre à juin est cruciale pour réduire le risque de dessiccation de ses œufs et pour favoriser ses larves par rapport à celles d’autres espèces d’odonates dans la région étudiée. Ceci pourrait nécessiter des travaux d’ingénierie écologique à l’échelle du bassin versant des mares, basés sur la modélisation de leur hydrologie en utilisant des données météorologiques et topographiques. Compte tenu des changements climatiques, et notamment de l’augmentation de l’imprévisibilité des précipitations dans la zone méditerranéenne, la mise en eau artificielle par un réseau d’irrigation pourrait être la garantie du maintien d’un nombre minimal de sites de reproduction pérennes pour l’espèce. L’irrigation pourrait également aider à contrôler les niveaux de salinités et à maintenir des niveaux d’eau élevés durant la phase inondée afin d’augmenter la valeur sélective des individus. La colonisation des mares créées par B. maritimus devrait être accélérée par la transplantation de tubercules et de rhizomes collectés sur le terrain. La végétation existante devrait être entretenue par la mise en place d’un pâturage dont le calendrier et la pression soient liés au régime hydrologique visé. Compte tenu de la dégradation passée des milieux temporaires saumâtres, un réseau de mares de ce type devrait être restauré ou recréé en utilisant L. macrostigma comme espèce étendard. Leur suivi sur le long terme aiderait à identifier les facteurs de succès ou d’échec de ces actions de conservation, et à améliorer la conception des projets à venir. À cet égard, de nouvelles recherches portant sur la réintroduction de L. macrostigma dans certaines mares restaurées sont nécessaires. Cette thèse représente une importante étude de cas sur la manière de prendre en considération les insectes menacés dans les stratégies de conservation de la biodiversité.
de Philippe Lambret, Martin Jeanmougin, Robby Stoks
In Journal of Insect Conservation, 27 (February, 2023)
En ligne : link.springer.com[...]
Freshwater insects have dramatically declined during the last decades. Lestes macrostigma is a damselfly of temporary brackish ponds, and is threatened in Europe. Better understanding its larval ecological requirements is imperative to inform conservation management measures and habitat restoration programs. We studied in a set of 33 temporary ponds the effect of 14 biotic and abiotic variables (including hydroperiod, pond surface area, water salinity, oviposition plant availability and predator relative abundance) on L. macrostigma larval abundance and adult size at emergence. Contrarily to our expectations, salinity level and oviposition plant availability did not drive the species larval abundance. Instead, the later the flooding date of the pond in autumn/winter the higher the larval abundance in the next spring. This effect seemed mediated by the aeshnid dragonfly larvae, as the size and relative abundance of these predators were lower in later flooded ponds. Larval abundance of L. macrostigma also increased with decreasing pond surface area. Lestes macrostigma adults tended to be bigger when they emerged from ponds with higher water levels, likely because deeper waters have lower water temperatures; this larger size may positively affect adult lifespan and fecundity. Our results contribute to explaining the species strong inter-annual variation in population abundance and further illustrate the threat of artificial early flooding of ponds for Mediterranean species.The impact of salinity on a saline water insect: Contrasting survival and energy budget
de Philippe Lambret, Lizanne Janssens, Robby Stoks
In Journal of Insect Physiology, 131 (May, 2021), 9
En ligne : www.sciencedirect.com[...]
Water salinity is a major driver of aquatic insects’ distribution. Saline species are usually generalists with high survival and performance at both low and high salinity levels. Yet, costs of high salinity may be underestimated as these are most often measured in terms of larval life history traits, while effects of larval stressors may only be detectable when looking at physiological traits and traits in the adult stage. Here, we assessed the lethal and sublethal physiological effects of embryonic and larval exposure to a range of salinity levels in the damselfly Lestes macrostigma, both during and after metamorphosis. This species inhabits temporary freshwaters where salinity increases during the drying phase. Salinity had no effect on egg hatching success within the range 2–9.5 g/L sea salt (conductivity range 3.45–14.52 mS/cm). With increasing salinity (up to 16 g/L, 23.35 mS/cm), growth rate decreased and larvae took longer to emerge and did so at a smaller size. Larval survival to metamorphosis increased with salinity up to 8 g/L (12.45 mS/cm) and then declined at 16 g/L. Exposure to salinity in the larval stage had no effect across metamorphosis on both the adult thorax muscle mass and flight performance, and the investment in immune function. Increasing salinity in the larval stage also had no effect on the energy available but increased the energy consumption in the adult stage, resulting in a lower net energy budget. These negative sublethal effects of increasing salinity hence bridged metamorphosis and contrasted with the mortality data, suggesting that the higher mortality at the low salinity levels selected for larvae with the best body condition. Our results highlight the importance of taking into account other life-history and physiological traits, besides mortality, ideally across different life stages, to better understand and predict consequences of increasing salinization on freshwater insects.Lestes macrostigma (Eversmann), the Dark Spreadwing
de David Chelmick, Philippe Lambret
In Journal of the British Dragonfly Society, 36(2) (November, 2020), 84-108
Lestes macrostigma (Dark Spreadwing) occurs across the southern Palearctic from the Atlantic coast as far east as Mongolia. It is locally common in the central part of its range, including Greece and Bulgaria, but becomes increasingly rare in the western parts of the region where, with notable exceptions, it is essentially coastal. It is very much associated with temporary, brackish and and saline habitats and, very often, with Bolboschoenus maritimus (Sea Club Rush). Many of its coastal habitats are under threat, especially from wetland transformation schemes of various types and, for tnat reason, the species is listed as Endangered in the European Red list.Estimating biodiversity changes in the Camargue wetlands: An expert knowledge approach
de Sara Fraixedas, Thomas Galewski, Sofia Ribeiro-Lopes, Jonathan Loh, Jacques Blondel, Hugo Fontes, Patrick Grillas, Philippe Lambret, Delphine Nicolas, Anthony Olivier, et al.
In PLOS ONE, 14(10) (24 oct. 2019), e0224235
En ligne : journals.plos.org[...]
Mediterranean wetlands are critical strongholds for biodiversity and the provision of ecosystem functions and services; yet, they are being severely degraded by a number of socio-economic drivers and pressures, including climate change. Moreover, we still lack comprehensive understanding of the extent to which biodiversity loss in Mediterranean wetlands will accelerate change in ecosystem processes. Here, we evaluate how changes in biodiversity can alter the ecosystem of the Camargue (southern France). We collected data on species presence/absence, trends and abundance over a 40-year period by combining observations from the scholarly literature with insights derived from expert knowledge. In total, we gathered more than 1500 estimates of presence/absence, over 1400 estimates of species abundance, and about 1400 estimates of species trends for eight taxonomic groups, i.e. amphibians, reptiles, breeding birds, fish, mammals, dragonflies (odonates), orthopterans and vascular plants. Furthermore, we used information on recently arrived species and invasive species to identify compositional changes across multiple taxa. Complementing targeted literature searches with expert knowledge allowed filling important gaps regarding the status and trends of biodiversity in the Camargue. Species trend data revealed sharp population declines in amphibians, odonates and orthopterans, while birds and plants experienced an average increase in abundance between the 1970s and the 2010s. The general increasing trends of novel and invasive species is suggested as an explanation for the changing abundance of birds and plants. While the observed declines in certain taxa reflect the relative failure of the protection measures established in the Camargue, the increasing exposure to novel and invasive species reveal major changes in the community structure of the different taxonomic groups. This study is the first attempt to assess changes in biodiversity in the Camargue using an expert knowledge approach, and can help manage the uncertainties and complexities associated with rapid social-ecological change in other Mediterranean wetlands.
de Julien Renet, Lisa Leprêtre, Jocelyn Champagnon, Philippe Lambret
In Herpetological Journal (The), 29(1) (January, 2019), 13-22
En ligne : www.thebhs.org[...]
The estimation of demographic parameters in wild populations is strengthened by individual identification. For amphibians, various techniques are used to either temporarily or permanently mark individuals for identification. Photo-identification of body patterns offers a non-invasive technique. However, the reliability of photo-recognition software is key to the reliable estimation of the true demographic parameters. In the current study, we assessed the effectiveness of fully-automated and semi-automated software: Wild-ID and APHIS. We used the cryptic salamander Hydromantes strinatii as our study species. We used the False Rejection Rate (FRR) of Top 1, Top 5 and Top 10 matches of chest and cloaca pictures. Finally, we assessed the bias induced by our FRR for the estimation of population size through simulation.Oviposition plant choice maximizes offspring fitness in an aquatic predatory insect
de Philippe Lambret, Imogen Rutter, Patrick Grillas, Robby Stoks
In Hydrobiologia, 10.1007/s10750-018-3507-1 (May 2018), 1-12
En ligne : link.springer.com[...]
Evidence for the adaptive value of oviposition site selection in terms of increased offspring fitness is rare in predatory insects. We tested this in the damselfly Lestes macrostigma that prefers the plant Bolboschoenus maritimus. We carried out two experiments with shoots containing eggs: we flooded (1) some shoots of the same type (i.e. combination of species and desiccation state) at different dates and (2) different shoot types at the same date. Earlier flooding increased hatching success. Because B. maritimus grows in deeper parts of temporary ponds, it is flooded before other plants after the drought season, suggesting that adult oviposition site selection is driven by lower egg desiccation risk. Independently of flooding date, hatching success was higher and larvae hatched earlier when eggs were laid in B. maritimus. Faster embryonic development enhances chances to complete larval development before pond desiccation and reduces costs associated with time stress. Offspring higher fitness was more constant between shoots of B. maritimus compared to the other types of shoot, suggesting that laying eggs in one shoot of this plant leads offspring to high fitness more surely. Our results indicate that adults choose oviposition plants maximizing offspring fitness (higher hatching success and faster embryonic development).Révision de la Liste rouge des libellules (Odonata) de Provence-Alpes-Côte d’Azur – version 2017
de Philippe Lambret, Charlotte Ronne, Stéphane Bence, Yoann Blanchon, Jonathan Blettery, Éric Durand, Marie-France Leccia, Michel Papazian
In Martinia, 33(1 - 2) (2017), 37 - 52
Dans la continuité de la déclinaison régionale du Plan national d’actions en faveur des Odonates, le risque d’extinction des Odonates de PACA a été réévalué, abrogeant ainsi la Liste rouge régionale de 2011. La disponibilité de dizaines de milliers de données, récoltées grâce à la dynamique de l’atlas régional, a permis de calculer les aires d’occurrence (EOO) et d’occupation (AOO) de chaque espèce. Cette réévaluation était donc nécessaire vis-à-vis de la méthodologie de l’UICN qu’il était alors possible d’appliquer de manière plus robuste et sur des bases plus étayées. Une analyse bibliographique a montré que nous n’avons en réalité aucune preuve que Sympecma paedisca, classé « éteint régionalement » (RE) en 2011, n’ait jamais été observé en PACA. Sur 70 espèces évaluées, huit sont menacées : Somatochlora arctica et Leucorrhinia dubia sont « en danger critique d’extinction » (CR) ; Coenagrion pulchellum et S. meridionalis sont « en danger d’extinction » (EN) ; Lestes macrostigma, C. caerulescens, S. alpestris et Sympetrum depressiusculum sont « vulnérables » (VU). Parmi les espèces non menacées, Gomphus graslinii, S. flavomaculata, Sympetrum danae et S. vulgatum le sont « quasiment » (NT). Les « données sont insuffisantes » (DD) pour Somatochlora metallica. La méthode UICN n’est « pas applicable » (NA) pour C. hastulatum, Aeshna grandis et Hemianax ephippiger. Le risque d’extinction des autres espèces présentes en PACA est une « préoccupation mineure » (LC). Par rapport à la Liste rouge de 2011, 26 espèces ont changé de catégorie (18 sont déclassées et trois surclassées), essentiellement pour des raisons méthodologiques, soulignant les plus grandes pertinence et robustesse de la présente réévaluation. Par rapport à la Liste rouge nationale de 2016, cinq et quatre espèces sont respectivement. plus et moins menacées en PACA que sur le reste du territoire métropolitain. La principale menace qui pèse sur les Odonates est la diminution de la superficie et de la qualité de leurs habitats en raison des activités humaines. Les politiques publiques mises en Tmuvre dans la région pour endiguer l’érosion de la biodiversité devraient notamment cibler les espèces évaluées ici comme menacées. Une nouvelle évaluation du risque d’extinction des Odonates de PACA devrait être réalisée dans quelques années en s’appuyant particulièrement sur les variations spécifiques d’EOO et AOO. /
In accordance with the regional implementation of the first national action plan for Odonata, the extinction risk of the Provence-AlpesCôte d’Azur (PACA) region dragonflies has been re-evaluated, thereby updating the 2011 regional Red List. Thousands of data were made available thanks to the regional atlas dynamic, which allowed us to compute the extent of occurrence (EOO) and the area of occupancy (AOO) for each species. Given the availability of this accurate and objective data, the re-evaluation of the Red List was necessary according to IUCN methods. A review showed that we actually have no evidence that Sympecma paedisca, considered in 2011 as Regionally Extinct (RE), had never been observed in the PACA region. Among the 70 species evaluated, eight are threatened: Somatochlora arctica and Leucorrhinia dubia are Critically Endangered (CR); Coenagrion pulchellum and S. meridionalis are Endangered (EN); Lestes macrostigma, C. caerulescens, S. alpestris, and Sympetrum depressiusculum are Vulnerable (VU). Among the non-threatened species, Gomphus graslinii, S. flavomaculata, Sympetrum danae and S. vulgatum are Nearly Threatened (NT). Somatochlora metallica was Data Deficient (DD). The IUCN methods were Not Applicable (NA) for C. hastulatum, Aeshna grandis and Hemianax ephippiger. Regarding their extinction risk, other species present in the PACA region are Least Concerned (LC). We classified 26 species in different categories compared to the 2011 regional Red List (of which 18 downlistings and three up-listings), primarily for methodological reasons, underlying that the present Red List is more relevant and robust than 2011’s. Compared to the 2016 national Red List, five and four species are, respectively, more and less threatened at the regional scale than at the French metropolitan scale. The main threat for the dragonflies is the decrease in habitat cover and quality due to human activities. Conservation politics should especially target the species listed here as threatened. A new evaluation of Odonata extinction risk should be planned in some years using especially EOO and AOO variations for each species.
de Philippe Lambret, Jean-Pierre Boudot, David Chelmick, Geert De Knijf, Éric Durand, Jacky Judas, Anthony Stoquert
In Odonatologica, 46(3-4) (2017), 154-206
En ligne : www.odonatologica.com[...]
Six field trips were carried out in the United Arab Emirates (UAE) and the Sul- tanate of Oman in autumn 2010, late winter 2013, spring 2014, autumn 2014, spring 2015 and spring 2016. We recorded 37 species at 87 localities, including new localities for some species of regional interest. Information on all observed Odonata species was recorded including their life stage, behaviour, habitat and water characteristics. Exuviae were also systematically collected. Urothemis thomasi was discovered at several new sites in the Hajar Mountains, the Dhofar and the Al Wusta regions, filling in the gap between the Dhofar and the Muscat area. In addition, new localities for two Arabian endemics: Arabicnemis caerulea and Arabineura khalidi were found, with their occurrence in the Dhofar region extending their known area and demonstrating that A. khalidi cannot be regarded as a strict Hajar en- demic. Important differences were noticed in the species composition of formerly surveyed localities, which may be ascribed to habitat degradation through management directed to- wards human recreation. Lastly, the well-known and diverse zoogeographical influences of Omani and the Emirati odonatofauna are confirmed with a large set of species of African origin in the Dhofar and a smaller set of species of Indomalayan origin visiting both the Dhofar and the northeast of the region during migrations and establishing, at least temporary, reproductive localities.
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 Philippe Lambret, Jérome Tourneur
In Martinia, 32(2) (12/01/2017), 93-115
Le Loir était connu pour abriter les seules populations de Gomphus graslinii recensées en Pays-de-la-Loire. Une étude a été menée en
2014-2015 afin de préciser la répartition de l’espèce dans le département du Maine-et-Loire et d’identifier les facteurs environnementaux conditionnant sa présence. Les résultats indiquent que les populations les plus importantes se concentrent sur le Loir mais que l’espèce se reproduit aussi sur les rivières Mayenne et Sarthe. L’étude de différentes variables montre que les facteurs environnementaux caractérisant le mieux les sites d’émergence de G. graslinii sur la rivière du Loir sont l’absence d’herbiers aquatiques, la présence d’une ripisylve continue générant un fort ombrage et la limitation du développement des semi-ligneux. L’éventuelle expansion récente de l’espèce est discutée. / The Loir River was known to host the only populations of Gomphus graslinii identified in the Pays-de-la-Loire region. A survey was conducted to map the distribution of the species on the course of the Loir River in the Maine-et-Loire department and to identify the environmentalfactors controlling its presence. The results show that the largest populations are found along the Loir River but that the species also breeds on the Mayenne and Sarthe Rivers. Studying different variables, we found that the most important environmental factors characterising the emergence sites of G. graslinii on the Loir River are the absence of aquatic vegetation, the presence of a continuous riparian forest inducing large shaded areas and the limitation of semi-ligneous plants on the banks. The possibility of a recent expansion of the species is discussed.
de François Mesléard, Michel Gauthier-Clerc, Philippe Lambret
In Aquatic Toxicology, 176 (July 2016), 24-29
En ligne : www.sciencedirect.com[...]
The potential impact of agricultural pesticides is a major concern with regard to biodiversity conservation. Pesticides are considered as one of the main causes of the worldwide decline of Amphibians. They are rarely used singly, but their cumulative impact and interaction are often neglected, as is the importance of the age or stage of the animal on which the impact of the molecules is assessed. The authors therefore tested the potential cumulative impact of the only authorized insecticide (Alphacypermetrine) and the main herbicide (Oxadiazon) used in French rice fields on four replicates of 25 eggs, young larvae and prometamorphosis tadpoles of the most abundant frog in paddies (Pelophylax perezi).
de Philippe Lambret
In Martinia, 32(1) (01/06/2016)
Dans le cadre du Plan national d’actions en faveur des Odonates,
la préférence des larves de l’espèce prioritaire Lestes macrostigma en termes de micro-habitat a été étudiée dans une mare temporaire de Camargue
(France). Les larves étaient environ 22 fois plus abondantes dans la
végétation aquatique que sur la boue du fond de la mare. Les raisons
vraisemblables de cette préférence sont (i) un comportement de défense face
aux prédateurs (dissimulation) et (ii) un meilleur accès aux ressources
trophiques. Par conséquent, il sera plus efficace de rechercher les larves de L. macrostigma dans la végétation aquatique lors de prospections ou de suivis spécifiques. Par ailleurs, ces résultats suggèrent que les hydrophytes sont un facteur important pour la conservation de cette espèce. / In the frame of the French action plan for Odonata, the microhabitat
preference of the larvae of the priority damselfly Lestes macrostigma
was studied at a temporary pond in the Camargue (Southern France). Larvae
were ca. 22 times more abundant among the aquatic vegetation than over the
mud at the bottom of the pond. The most likely reasons for this micro-habitat preference are (i) a sheltering behaviour against predators and (ii) a higher access to trophic resource. As a consequence, it is worth searching for L. macrostigma larvae preferably among the hydrophytes during specific surveys. With conservation regards, hydrophytes seem to be an important factor for this species.Etude de l’écologie de Lestes macrostigma et restauration de son habitat
de Philippe Lambret, Olivier Boutron, Gregoire Massez
In Courrier de la Nature (Le), 296 (n° spécial), 66-69
de Natalia Matushkina, Philippe Lambret, Stanislav Gorb
In Zoology (mars 2016), 22 p.
En ligne : www.sciencedirect.com[...]
Oviposition site selection is a crucial component of habitat selection in dragonflies. The presence of appropriate oviposition plants at breeding waters is considered to be one of the key habitat determinants for species laying eggs endophytically. Thus, Lestes macrostigma, a species which is regarded as threatened in Europe because of its highly disjunct distribution, typically prefers to lay eggs in the sea club rush Bolboschoenus maritimus. However, little is known about how the anatomical and mechanical properties of plant tissues determine the choice of L. macrostigma females. The authors examined green shoots of six plant species used by L. macrostigma for oviposition, either in the field (actual oviposition plants) or under experimental conditions (potential oviposition plants), to analyse anatomical and mechanical properties of shoots in a framework of known preferences regarding plant substrates for oviposition.
de Philippe Lambret, A. Besnard, N. Matushkina
2015
de Philippe Lambret, A. Besnard, N. Matushkina
2015
Biotic and abiotic features impact the breeding success of animals and thereby induce selection pressures for habitat selection. Little is known about the plant selection by predatory insects which lay their eggs within plants. In previous work, the authors have highlighted that during oviposition males of Lestes macrostigma—an endangered dragonfly species—prefer to land on Bolboschoenus maritimus and dead shoots of Juncus maritimus but disfavour living shoots in that species, and that females seem to prefer dead material during substrate examination. In this study the authors assessed behavioural preference in females during substrate examination, substrates suitability for oviposition, the effort females had to make to lay their eggs and their resulting oviposition rate. We show L. macrostigma has a preference for B. maritimus and, albeit to a lesser extent, for dead substrates.
