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The genus Corbicula contains one of the most common and successful aquatic invasive species to North America. Prior to 2015 two predominant species of Corbicula were known from the United States--C. fluminea and C. largillierti, referred to as Forms A and 15, respectively. Form A has spread throughout most of the U.S., while Form 15 is mainly contained in the Midwest and southern U.S. In 2015 a novel Corbicula, known as Form 11, was discovered in the Illinois River, at Marseilles. Illinois, and was later reported from the Ohio River. Our primary objective for this study was to report additional records of Form D, with a focus on the upper Illinois River watershed. Surveys during summer 2017 verified the presence of Form D in the Tennessee and Mississippi rivers, as well as multiple new locations in the Des Plaines and Illinois rivers, where all three Corbicula forms coexist., Introduction Members of the genus Corbicula are moderatelv-sized freshwater clams native to the temperate/ tropical regions of Asia, Africa, and Australia and have become one of the most common and [...]

Introduced and invasive species are emerging as a significant threat to biodiversity, especially to endemic species, worldwide. One of the ways in which introduced species might impact native species is through competition for space, mediated through interspecific interactions. The Red-whiskered Bulbul (Pycnonotus jocosus) is one such species that was introduced to the central Nicobar from mainland India in the late 1800s. Several bird studies from the region postulate that it may pose a serious threat to the endemic Nicobar Bulbul (Ixos nicobariensis). In this study we explored broad patterns in habitat-use intensity of these 2 bulbuls using point counts. Further, we conducted playback trials to assess the nature of their interspecific interactions. Our results show that these 2 species show segregation in habitat use. The Nicobar Bulbul is a forest-dwelling species showing preference for primary forests, while the Red-whiskered Bulbul occurs in the secondary habitats around human habitation. Further, the playback experiments failed to yield any interspecific response indicating a lack of interspecific aggression. We believe that both species, being evolutionarily distinct, naturally segregate themselves on the currently available habitats on these islands. However, destruction of primary forest for plantations and infrastructure development might be a more immediate threat to the endemic Nicobar Bulbul. Received 28 September 2018. Accepted 9 February 2019. Key words: invasive, Nicobar Bulbul, playback. Redwhiskered Bulbul, space use Las especies introducidas e invasoras estan emergiendo como una amenaza significativa para la biodiversidad en todo el mundo, especialmente para fas especies endemicas. Una de las maneras en las que las especies introducidas podrian impactar a las nativas es a traves de la competencia por espacio, mediada a traves de interacciones interespecificas. El bulbul Pycnonotus jocosus es una de esas especies que fue introducida en Nicobar central proveniente de la India de tierra firme a finales del siglo XIX. Varios estudios de la region postulan que podria significar una amenaza seria al bulbul endemico de Nicobar. Ixos nicobariensis. En este estudio. exploramos los patrones amplios de intensidad de uso de habitat de estos dos bulbules utilizando conteos por puntos. Adcmas. hicimos pruebas de playback para determinar la naturaleza de sus interacciones interespecificas. Nuestros resultados muestran que estas dos especies muestran segregacion en el uso de habitat. /. nicobariensis es una especie habitante de bosques que muestra preferencia por bosques primarios, mientras que P. jocosus se encuentra en los habitats secundarios, cerca de asentamientos humanos. Adcmas. los experimentos con playbacks no registran respuestas interespecificas. lo que indica ausencia de agresion interespecifica. Creemos que ambas especies, siendo evolutivamente distintas. se segregan naturahnente en los habitats que actualmente estan disponibles en estas islas. Por ello, la destruccion de bosques primarios para plantaciones y dcsarrollo de infraestructura podrian ser una amenaza mas inmediata al bulbul endemico de Nicobar. Palabras clave: invasivo, playback, uso del espacio, Islands are ecologically unique as they are known to be laboratories of evolution (Wagner and Funk 1995, Grant 1998). They present ideal systems for studies on ecological patterns and processes. [...]

Eight eastern U.S. prairie sites were sampled for exotic species abundance in relation to levels of native diversity; including species and functional richness, species evenness, and functional group similarity for the alpha (quadrat; 1 [m.sup.2]; n = 508) and gamma (site; n = 8) scales. Spearman's rank co- efficient analyses found only a weak negative correlation (P < 0.001; [r.sub.s] = -0.14) with species richness and exotic abundance; and was nonsignificant for the other measures of diversity. Principal Components Analysis (PCA) indicated instead that exotic abundance was more correlated with higher soil parameter values among the sites. Both Lonicera japonica and Lespedeza cuneata represented 90% of the exotic cover from among the study sites., INTRODUCTION As a result of severe fragmentation and periodic disturbance events, remnant prairies are likely susceptible to high levels of biological invasion from exotics with the potential for loss of [...]

The House Sparrow (Passer domesticus) and the brown anole (Anolis sagrei) are both invasive species in South Florida where they have occurred in sympatry for nearly 100 years. While the opportunistic feeding style of the House Sparrow is likely a large contributor to its success as an invader, there have been no reported incidents of House Sparrows consuming vertebrate prey. Here we report the first predation of a vertebrate prey (A. sagrei) by House Sparrows, suggesting an evolutionary shift in dietary preference following novel invasive species interactions. Received 30 May 2018. Accepted 18 August 2018. Key words: Anolis, behavior, evolution, interaction, invasive, predation El consume dc presas vertebradas por el gorrion Passer domesticus: un ejemplo de respuestas evolutivas a interacciones interespecificas al interior de comunidades novedosas EI gorrion Passer domesticus y la lagartija Anolis sagrei son especies invasoras en el sur de Florida donde ambas sc han encontrado en simpatria por cerca de 100 anos. Si bien el estilo de alimcntacion de este gorrion es posiblemente un factor que contribuye en gran medida a su exito como invasor, no hay incidentes reportados de esta especie consumiendo presas vertebradas. Aqui reportamos la primera depredacion dc una presa vertebrada (A. sagrei) por P. domesticus, la cual sugicre un giro evolutivo en preferencias de dieta siguiendo nuevas interacciones entre especies invasoras. Palabras clave: Anolis, comportamiento, depredacion. evolucion. invasor, The global proliferation of invasive species causes major damage to native ecosystems while also providing unique opportunities to study novel species interactions. South Florida is home to the largest number [...]

We studied the consequences of a nonnative species introduction and changes in temperature on early mortality and recruitment of native rainbow smelt (Osmerus mordax) and nonnative alewife (Alosa pseudoharengus) in Lake Champlain using a simulation model. Distribution patterns of adults and young-of-the-year (YOY) fish were predicted using a model based on observed distribution of different age groups as a function of temperature and light profiles simulated on a daily basis. Mortality rates averaged over the growing season were calculated as a function of fish densities and overlap between adults and YOY. Survival of YOY rainbow smelt and alewife depended on which predator was most abundant. Rainbow smelt YOY mortality rates are highest when rainbow smelt adults are abundant, and alewife YOY mortality rates are highest when alewife adults are abundant, potentially allowing coexistence. August and September mortality rates were higher in the climate change scenario because of increased overlap of adults and YOY of both species. These results indicate that accounting for spatiotemporal fish distribution patterns can be important when forecasting the interacting effects of climate change and aquatic invasive species on fish recruitment. Nous avons etudie les consequences de l'introduction d'une espece non indigene et des changements de temperature sur la mortalite precoce et le recrutement d'eperlans arc-en-ciel (Osmerus mordax) indigenes et de gaspareaux (Alosapseudoharengus) non indigenes dans le lac Champlain en utilisant un modele de simulation. Les motifs de repartition de poissons adultes et jeunes de l'annee ont ete predits en utilisant un modele base sur la repartition observee de differents groupes d'age en fonction de la temperature et de profiles de lumiere simules sur une base quotidienne. Les taux de mortalite moyens pour la saison de croissance ont ete calcules en fonction des densites de poissons et du chevauchement des adultes et des jeunes de l'annee. La survie des eperlans arc-en-ciel et des gaspereaux jeunes de l'annee depend du predateur qui est le plus abondant. Les taux de mortalite des eperlans arc-en-ciel jeunes de l'annee sont les plus eleves quand les eperlans arc-en-ciel adultes sont abondants et les taux de mortalite des gaspareaux jeunes de l'annee sont les plus eleves quand les gaspareaux adultes sont abondants, permettant possiblement une coexistence. Les taux de mortalite en aout et septembre sont les plus eleves dans le scenario de changement climatique en raison du chevauchement accru d'adultes et de jeunes de l'annee des deux especes. Ces resultats indiquent que la prise en consideration des motifs de repartition spatiotemporelle des poissons peut etre importante pour la prediction des effets interactifs des changements climatiques et d'especes aquatiques envahissantes sur le recrutement de poissons. [Traduit par la Redaction], Introduction Environmental and biological mechanisms causing variable recruitment in fish populations have long been of interest to fisheries science (Cushing 1975; Wootton 1990; Diana 1995) and have received increased attention [...]

By the time Charles Darwin landed in Brazil in 1832 while on his voyage on the HMS Beagle, Europeans had known for centuries that the tropics house an extraordinary variety [...]

The New River Basin (NRB) of Tennessee has many rare endemic aquatic communities. One such community is that of freshwater mussels, which are experiencing a precipitous population decline due to the fouling and pollution of their freshwater systems. Silos containing live individuals of the nonnative Asian clams (Corbicula fluminea) were placed in several localities in streams of the NRB that receive mine drainage. This drainage is commonly associated with elevated conductivity typical of pollution that may impair native mussel health. This study of five impacted streams within the NRB, and a control stream of similar ecology, uses a stepwise multiple regression analysis to test this association. After accounting for factors such as temperature, results confirm that growth rates of these sentinel clams are significantly related to conductivity, and that these clams may be useful bioindicators of stream habitat quality for native mussels. KEY WORDS: aquatic ecology, bioindicating species, coal mining, conductivity, conservation, Corbicula fluminea, endemic species, freshwater mussels, invasive species, native species, pollution, sentinel species, stream habitat, INTRODUCTION Coal mining has many impacts on aquatic ecosystems, including acidification, metal loading, and fly ash disposal (Giam et al. 2018). Surface mining can be especially harmful, impairing freshwater resources [...]

The physiological tolerances of invasive species can be important predictors of geographic range expansion. Further, determining salinity tolerances can inform natural resource managers as to the ability of a freshwater species to invade estuarine habitats. Native to South America, the island apple snail Pomacea maculata (family Ampullariidae) is an invasive freshwater gastropod that is currently established across much of the southeastern United States, including South Carolina. The island apple snail is considered an invasive species because of the negative impacts of its intense grazing, high fecundity, and ability to out-compete native species. Further, the island apple snail can also serve as a potential to host the rat lungworm nematode parasite (Angiostrongylus cantonensis), which can cause eosinophilic meningitis in humans. Despite these known potential impacts, knowledge of biology of P. maculata in South Carolina is limited. The objective of this study was to determine the salinity tolerance of P. maculata hatchlings. Although previous studies on the salinity tolerance of P. maculata have been conducted, physiological tolerances can often vary regionally. Because of this potential for regional differences in salinity tolerance, determining the salinity tolerance of P. maculata specific to South Carolina is important in improving the understanding of its invasion/dispersion potential among brackish habitats in South Carolina. This knowledge will help resource managers to develop more effective control and/or eradication strategies. Newly hatched P. maculata obtained from egg clutches deposited by adult snails in a biosecure laboratory were placed in each of five salinity treatments (0, 4, 8, 12, and 16), and mortality was assessed daily for 14 days. Intraspecific variation at the regional scale in salinity tolerance has been documented in other species; thus, the survival of hatchlings from four separate mating pairs was assessed. Kaplan-Meier survival analysis was conducted to determine median survival probabilities, and differences in mean survival were determined using Kruskal-Wallis tests with post hoc Dunn's tests. An L[D.sub.50] value was determined by conducting a logistic regression analysis. A survival of 100% was observed at 0 salinity and 0% survival was observed at salinities of both 12 and 16. Survival probabilities at salinities of 4 and 8 were 0.925 and 0.156, respectively. There were no differences in survival among hatchlings from the different mating pairs. In relation to salinity, an L[D.sub.50] value of 6.39 was calculated. These results demonstrate the ability of P. maculata to survive salinities as high as 8, suggesting that this species could be capable of becoming established in upstream estuarine habitats in coastal South Carolina. KEY WORDS: Pomacea maculata, gastropod, freshwater, non-native, Ampullariidae, INTRODUCTION The ability to predict accurately an invasive species' potential range of impact is paramount in risk assessment, monitoring, and overall management (Stohlgren & Schnase 2006). Further, the physiological tolerances [...]

Invasive species cause ecological and economic impacts on invaded ecosystems, although the presence of native species hampers the propagation of invasive species due to biotic resistance. We tested the effects of grazing by the native channeled applesnail (Pomacea canaliculata (Lamarck, 1828)) over the invasive macrophyte Hydrilla verticillata (L. f.) Royle (water thyme) and the native macrophyte Egeria najas Planch to evaluate the potential of herbivory as a mechanism to resist invasion. Both macrophyte species were offered, individually and combined, as food resources to the snail to evaluate its feeding preference. The macrophyte energy content and stiffness were also measured. The results indicate a higher H. verticillata biomass consumption by P. canaliculata when this macrophyte was available both individually and combined with E. najas, suggesting that H. verticillata is more palatable to the snail, despite this macrophyte being stiffer than the native one. Therefore, P. canaliculata may offer resistance to H. verticillata invasion. The feeding preference and high rates of herbivory by this snail on H. verticillata likely are associated with the higher energy content of the invasive, compared with the native, macrophyte. Experiments combining different food availabilities and snail densities are necessary to evaluate the biological control capacity of P. canaliculata under different scenarios. Key words: floodplain, grazing, biotic resistance, non-native macrophyte, Hydrilla verticillata, Egeria najas, Pomacea canaliculata. Resume: Si les especes envahissantes ont des impacts ecologiques et economiques sur les ecosystemes, la presence d'especes indigenes entrave la propagation d'especes envahissante grace a la resistance biotique. Nous avons verifie les effets du broutage par l'escargot indigene Pomacea canaliculata (Lamarck, 1828) du macrophyte envahissant Hydrilla verticillata (L. f.) Royle et du macrophyte indigene Egeria najas Planch, afin d'evaluer le potentiel de l'herbivorie comme mecanismes de resistance aux envahissements. Les deux especes de macrophytes ont ete offertes, seules ou combinees, comme ressources alimentaires a l'escargot pour evaluer la preference d'alimentation de ce dernier. La teneur energetique et la rigidite des macrophytes ont aussi ete mesurees. Les resultats indiquent une plus forte consommation de biomasse de H. verticillata par P. canaliculata quand ce macrophyte est disponible, tant individuellement que combine aE. najas, ce qui indiquerait que H. verticillata est plus appetissant pour l'escargot, malgre le fait qu'il est plus rigide que le macrophyte indigene. Pomacea canaliculata pourrait donc offrir une resistance a l'envahissement de H. verticillata. La preference alimentaire de cet escargot pour H. verticillata et ses taux eleves d'herbivorie sur cette plante sont vraisemblablement associes a la teneur energetique plus grande de ce macrophyte envahissant que celle du macrophyte indigene. Des experiences qui combinent differentes disponibilites d'aliments et densites d'escargots sont necessaires pour evaluer la capacite de contr[delta]le biologique de P. canaliculata dans differents scenarios. [Traduit par la Redaction] Mots-cles : plaine inondable, broutage, resistance biotique, macrophyte non indigene, Hydrilla verticillata, Egeria najas, Pomacea canaliculata., Introduction Herbivores may prevent the establishment of invasive species and it is one of the mechanisms involved in the biotic resistance hypothesis (Elton 1958; Catford et al. 2009). Herbivory is [...]

The Limpkin (Aramus guarauna) is a medium-sized wading bird found in peninsular Florida and Central and South America, whose distribution is strongly tied to the presence of apple snails (genus Pomacea). Historically. Limpkins have been infrequently observed in the lower Apalachicola-Chattahoochee-Flint (ACF) watershed, including Lake Seminole, the most downstream reservoir in the system. In the past decade in Lake Seminole, a rapid increase in the nonnative P. maculata has been documented. In 2016, a Limpkin was observed in the lake, and we made efforts to document all subsequent Limpkin observations there. In the following year, we observed Limpkins (including several mating pairs) each month from February to July 2017. Limpkins were only observed in the Flint River section of the reservoir, the same area where the greatest abundance of P. maculata has been documented. We hypothesize the rapid increase of P. maculata is responsible for the recent regular Limpkin observations at the lake because observations of Limpkins prior to the recent expansion of P. maculata were rare and infrequent. Apple snails are likely to expand within the southeastern United States in the future, thereby creating additional suitable habitat for Limpkins and other specialist avian predators of apple snails. Received 28 July 2017. Accepted 8 August 2018. Key words: apple snail, invasive species, Limpkin, predator-prey interaction, range expansion. (Spanish)--El carao o carrao (Aramus guarauna) cs un ave vadcadora mcdiana que se encuentra en la Florida peninsular. Centra y Sudamerica cuya distribucion esta ligada a la presencia de caracoles del genero Pomacea. Historicamcnte, A. guarauna fue observada con poca frecuencia en la cuenca baja de Apalichola-Chattahoochee-Flint (ACF), incluycndo Lake Seminole, el embalse mas aguas abajo del sistema. En la decada pasada se documento un rapido incremento de Pomacea no-nativos en Lake Seminole. En 2016. se observo un A. guarauna en el lago c hicimos esfucrzos para documentar todas las observaciones subsecuentes de esta especie. Al siguiente ano, observamos a A. guarauna (incluidos varios individuos cmparejados) cada mes de febrero a Julio de 2017. Solo observamos a A. guarauna en la seccion de Flint River de estc embalse, misma donde se ha documentado la mayor abundancia de P. maculata. Hipotetizamos que el rapido incremento de P. maculata es responsable de las observaciones regulares recientes de A. guarauna debido a que !os rcgistros de esta ave antes de la expansion reciente de P. maculata eran raras y poco frccuentes. Es muy probable que los caracoles eolonicen otros sitios del sureste de los Estados Unidos en el futuro, creando con ello habitat disponible adicional para A. guarauna y para otras aves depredadoras cspecialistas de cste caracol. Palabras clave: especies invasoras, expansion de rango, interacciones depredador-presa, Pomacea maculata., Limpkins (Aramus guarauna) are largely solitary, medium-sized, marsh birds common throughout wetlands and marshes of peninsular Florida, the Caribbean, and Central and South America. The Limpkin call is easily distinguished [...]

Alien invasive species are problematic both economically and ecologically, particularly on islands. As such, understanding how they interact with their environment is necessary to inform invasive species management. Here, we ask the following questions: What are the main functional traits that correlate with invasion success of alien plants on Robben Island? How does phylogenetic structure shape biotic interactions on the island? Using multiple approaches to explore these questions, we found that alien invasive species flower later during the year and for longer period, although flowering phenology was sensitive to alternative starting date. Additionally, we observed that alien invasive species are mostly abiotically pollinated and are generally hermaphroditic whilst their native counterparts rely on biotic pollinators, flower earlier, and are generally dioecious, suggesting that alien invasive and native species use different ecological niches. Furthermore, we found a facilitative interaction between an alien invasive legume and other invasive plants as predicted by the invasional meltdown hypothesis, but this does not influence the phylogenetic structure of plant communities. Finally, phylogenetically diverse set of native species are less receptive to alien invasive species. Collectively, our findings reveal how biotic interactions and phylogenetic relatedness structure alien invasive--native co-existence. Key words: Acacia cyclops, biological invasions, evolutionary history, functional traits, invasional meltdown, niche partition. Les especes envahissantes sont problematiques tant sur le plan economique qu'ecologique, particulierement sur des iles. En tant que tel, il est necessaire de comprendre comment elles interagissent avec leur environnement pour guider leur gestion. Dans ce travail, les auteurs posent les questions suivantes : Quels sont les principaux caracteres fonctionnels qui sont correles avec le potentiel envahissant des especes exotiques sur Robben Island? Comment la structure phylogenetique faconne-t-elle les interactions biotiques sur l'ile? A l'aide d'approches multiples, les auteurs trouvent que les especes exotiques fleurissent plus tard et pendant une plus longue periode, bien que la phenologie de la floraison etait sensible a une date alternative de debut de floraison. De plus, les auteurs observent que les especes envahissantes sont principalement sujettes a une pollinisation abiotique et sont generalement hermaphrodites, tandis que les especes indigenes beneficient de pollinisateurs biotiques, fleurissent plus tot et sont generalement dioiques, ce qui suggere que les especes exotiques et indigenes occupent des niches ecologiques differentes. Aussi, une interaction facultative entre une legumineuse envahissante et d'autres plantes envahissantes, tel que predit sur la base de l'hypothese de l'effondrement des especes indigenes, a ete observee, mais celle-ci n'influence pas la structure phylogenetique des communautes vegetales. Finalement, des communautes de plantes indigenes qui sont diversifiees sur le plan phylogenetique sont moins sujettes a l'envahissement par des especes exotiques. Ensemble, ces resultats revelent comment les interactions biotiques et la parente phylogenetique influencent la coexistence entre especes exotiques et indigenes. [Traduit par la Redaction] Mots-cles : Acacia cyclops, invasions biologiques, histoire evolutive, caracteres fonctionnels, effondrement des especes indigenes., Introduction The stability and productivity of ecosystems, as well as their ability to provide a diverse set of ecological services, correlate with their phylogenetic structure (Cadotte et al. 2008, 2009; [...]

Introduction The arrival and establishment of marine non-indigenous species can have dramatic effects on the structure and functioning of coastal ecosystems (Galil 2007; Wallentinus and Nyberg 2007; Ehrenfeld 2010). Early [...]

Madagascar is a prime evolutionary hotspot globally, but its unique biodiversity is under threat, essentially from anthropogenic disturbance. There is a race against time to describe and protect the Madagascan endangered biota. Here we present a first molecular characterization of the micromoth fauna of Madagascar. We collected 1572 micromoths mainly using light traps in both natural and anthropogenically disturbed habitats in 24 localities across eastern and northwest Madagascar. We also collected 1384 specimens using a Malaise trap in a primary rain forest at Andasibe, eastern Madagascar. In total, we DNA barcoded 2956 specimens belonging to 1537 Barcode Index Numbers (BINs), 88.4% of which are new to BOLD. Only 1.7% of new BINs were assigned to species. Of 47 different families found, Dryadaulidae, Bucculatricidae, Bedelliidae, Batrachedridae, and Blastobasidae are newly reported for Madagascar and the recently recognized Tonzidae is confirmed. For test faunas of Canada and Australia, 98.9%-99.4% of Macroheterocera BINs exhibited the molecular synapomorphy of a phenylalanine in the 177th complete DNA barcode codon. Non-macroheteroceran BINs could thus be sifted out efficiently in the Malaise sample. The Madagascar micromoth fauna shows highest affinity with the Afrotropics (146 BINs also occur in the African continent). We found 22 recognised pests or invasive species, mostly occurring in disturbed habitats. Malaise trap samples show high temporal turnover and alpha diversity with as many as 507 BINs collected; of these, astonishingly, 499 (98.4%) were novel to BOLD and 292 (57.6%) were singletons. Our results provide a baseline for future surveys across the island. Key words: Africa, invasive alien species, Lepidoptera, Malaise trap, plant pests. Madagascar est un haut lieu de l'evolution au niveau mondial, mais sa biodiversite unique est menacee, essentiellement en raison de perturbations anthropogeniques. Une course contre la montre est engagee pour decrire et proteger le biote malgache menace. Dans ce travail, les auteurs presentent une premiere caracterisation moleculaire des << microlepidopteres >> de Madagascar. Les auteurs ont recolte 1572 specimens en utilisant principalement des pieges lumineux (dans des milieux tantot naturels, tantot perturbes par l'Homme) au sein de 24 localites dispersees a travers l'est et le nord-ouest de Madagascar. Ils ont aussi collecte 1384 specimens a l'aide d'un piege Malaise dans une foret primaire humide a Andasibe. Au total, les codes-barres ADN ont ete sequences pour 2956 specimens correspondant a 1537 BIN, dont 88,4 % sont inedits dans BOLD. Seuls 1,7 % des nouveaux BIN ont ete assignes a une espece connue. Parmi les 47 familles trouvees, les Dryadaulidae, Bucculatricidae, Bedelliidae, Batrachedridae et Blastobasidae sont signales pour la premiere fois de Madagascar. La faune etudiee presente la plus grande affinite avec l'ecozone afrotropicale (dans laquelle se retrouvent 146 BIN). Les auteurs ont trouve 22 ravageurs connus ou especes envahissantes, principalement dans les habitats perturbes. Les specimens provenant des pieges Malaise different au fil du temps et presentent une grande diversite alpha, leur total pouvant atteindre 507 BIN. Parmi ceux-ci, etonnamment, 499 (98,4 %) sont inedits dans BOLD et 292 (57,6 %) ont ete vus une seule fois. Ces resultats fournissent un referentiel pour de futures etudes dans d'autres regions de l'ile. Mots-cles : Afrique, especes envahissantes, Lepidoptera, piege Malaise, ravageurs de plantes., Introduction Madagascar is one of the top priority global hotspots for biodiversity conservation with high endemicity and under large anthropogenic pressure (Vences et al. 2009). There is an urgent need [...]

Levels of carbon dioxide (C[O.sub.2]) that have been proposed for aquatic invasive species control (24 000-96 000 [mu]atm partial pressure of C[O.sub.2] (PC[O.sub.2]); 1 atm = 101.325 kPa) were tested on two juvenile mussels, the fat-mucket (Lampsilis siliquoidea) and the US federally endangered Higgins' eye (Lampsilis higginsii). A suite of responses (survival, growth, behavior, and gene expression) were measured after 28 days of exposure to C[O.sub.2] and 14 days postexposure. The 28-day LC[O.sub.20] (concentration lethal to 20% of organisms) was lower for L. higginsii (31800 [mu]atm PC[O.sub.2], 95% confidence interval (CI) 15 000-42 800 [mu]atm) than for L. siliquoidea (58 200 [mu]atm PC[O.sub.2], 95% CI 45 200-68 100 [mu]atm). Treatment-related reductions occurred in all measures of growth and condition. Expression of chitin synthase, key for shell formation, was downregulated at 28 days of exposure. Carbon dioxide caused narcotization and movement to the substrate surface of mussels, behaviors that could increase mortality by predation and displacement. We conclude that survival and growth of juvenile mussels could be reduced by continuous exposure to elevated C[O.sub.2], but recovery may be possible with shorter-duration exposure.Les concentrations de dioxyde de carbone (C[O.sub.2]) proposees pour le controle d'especes aquatiques envahissantes (pression partielle de C[O.sub.2] (PC[O.sub.2]) de 24 000-96 000 [mu]atm; 1 atm = 101,325 kPa) ont ete testees sur des moules juveniles Lampsilis siliquoidea (lampsiles siliquoides) et Lampsilis higginsii, cette derniere espece figurant sur la liste federale des especes menacees des Etats-Unis. Differentes reactions (survie, croissance, comportement et expression genique) ont ete mesurees apres une exposition de 28 jours au C[O.sub.2], puis 14 jours apres l'exposition. La CL20 (concentration letale pour 20 % des organismes traites) apres 28 jours etait plus faible pour L. higginsii (PC[O.sub.2] : 31 800 [mu]atm; intervalle de confiance au seuil de 95 % (IC 95 %) : 15 000 42 800 [mu]atm) que pour L. siliquoidea (PC[O.sub.2]: 58 200 [mu]atm, IC 95 % : 45 200 - 68 100 [mu]atm). Des baisses associees au traitement ont ete observees pour toutes les mesures de la croissance et de l'embonpoint. L'expression de la chitine synthase, qui joue un role cle dans la formation de la coquille, etait modulee vers le bas apres l'exposition de 28 jours. Le dioxyde de carbone a cause la narcotisation et le desenfouissement des moules, des comportements qui pourraient accroitre la mortalite par predation et le deplacement. Nous concluons que la survie et la croissance des moules juveniles pourraient etre reduites par l'exposition soutenue a des concentrations elevees de C[O.sub.2], mais qu'un retablissement pourrait etre possible pour des expositions de courte duree. [Traduit par la Redaction], IntroductionElevated atmospheric carbon dioxide (C[O.sub.2]) is most recognized for its role in climate change and ocean acidification, but purposeful infusion into select aquatic systems is being pursued as a tool [...]