|
David Renault, Manon C. M. Hess, Julie Braschi, Ross N. Cuthbert, Marta G. Sperandii, Manuele Bazzichetto, Olivier Chabrerie, Gabrielle Thiébaut, Elise Buisson, Frédéric Grandjean, Anne-Kristel Bittebiere, Maud Mouchet, François Massol. (2022). Advancing biological invasion hypothesis testing using functional diversity indices (Vol. 834).
Abstract: Pioneering investigations on the effects of introduced populations on community structure, ecosystem functioning and services have focused on the effects of invaders on taxonomic diversity. However, taxonomic-based diversity metrics overlook the heterogeneity of species roles within and among communities. As the homogenizing effects of biological invasions on community and ecosystem processes can be subtle, they may require the use of functional diversity indices to be properly evidenced. Starting from the listing of major functional diversity indices, alongside the presentation of their strengths and limitations, we focus on studies pertaining to the effects of invasive species on native communities and recipient ecosystems using functional diversity indices. By doing so, we reveal that functional diversity of the recipient community may strongly vary at the onset of the invasion process, while it stabilizes at intermediate and high levels of invasion. As functional changes occurring during the lag phase of an invasion have been poorly investigated, we show that it is still unknown whether there are consistent changes in functional diversity metrics that could indicate the end of the lag phase. Thus, we recommend providing information on the invasion stage under consideration when computing functional diversity metrics. For the existing literature, it is also surprising that very few studies explored the functional difference between organisms from the recipient communities and invaders of the same trophic levels, or assessed the effects of non-native organism establishment into a non-analogue versus an analogue community. By providing valuable tools for obtaining in-depth diagnostics of community structure and functioning, functional diversity indices can be applied for timely implementation of restoration plans and improved conservation strategies. To conclude, our work provides a first synthetic guide for their use in hypothesis testing in invasion biology.
Keywords: Alien invasive species Community-weighted trait mean Diversity indices Functional traits Invasibility Invasiveness
Programme: 136
|
|
|
Lassalle Coralie. (2022). Apport des isotopes de l’eau pour comprendre la dynamique climatique et le cycle hydrologique en Terre Adélie.
Abstract: Dans un contexte de réchauffement climatique, la compréhension de l’évolution passée et future du climat dans le monde représente un enjeu majeur, dans la mesure où la calotte Antarctique peut contribuer à la hausse du niveau marin de près de 60 m. De ce fait, il est important d’appréhender et de documenter la variabilité climatique récente impactant le bilan de masse de surface antarctique, plus spécifiquement dans les régions côtières. Néanmoins, les enregistrements issus des observations instrumentales et satellitaires sont bien trop courts pour faire la distinction entre la variabilité naturelle du signal climatique et l’impact anthropique. D’où le lancement du raid scientifique ASUMA (« Improving the Accurancy of SUrface Mass balance of Antarctica »), dans le cadre de l’ANR (« Agence Nationale de la Recherche »), en Terre Adélie, zone côtière à fort taux d’accumulation caractérisée par la présence de vents catabatiques, afin de mieux connaitre l’évolution actuelle du bilan de masse. Un volet du projet est d’analyser la composition isotopique des carottes de névé dans l’objectif de fournir des informations sur le cycle hydrologique atmosphérique et la dynamique climatique. D’ailleurs, Sentia GOURSAUD (2018) montre que, dans la région côtière de Terre Adélie, la composition isotopique ne dépend pas que de la température de surface locale mais qu’elle est aussi sous l’influence d’autres facteurs (dynamique atmosphérique, sources et transport de l’humidité, phénomènes post-déposition). Dans ce rapport, deux sites de forages de carottes courtes du programme ASUMA ont été étudiés dans l’objectif de faire un transect le long de la pente menant au haut plateau antarctique, entre les points D47 à 1550 m d’altitude et STOP_0 à 2460m. Les mesures isotopiques effectuées ont permis de reconstruire la variabilité climatique sur les 50 dernières années grâce à une méthode analytique continue, l’analyse en flux continu ou CFA (« Continuous Flow Analysis »). Bien que cette méthode soit utilisée en laboratoire depuis quelques années, elle a été récemment développée au LSCE sur les carottes de névé.
Programme: 1205
|
|
|
Steffen M. Noe, Ksenia Tabakova, Alexander Mahura, Hanna K. Lappalainen, Miriam Kosmale, Jyri Heilimo, Roberto Salzano, Mattia Santoro, Rosamaria Salvatori, Andrea Spolaor, Warren Cairns, Carlo Barbante, Fidel Pankratov, Angelika Humbert, Jeroen E. Sonke, Kathy S. Law, Tatsuo Onishi, Jean-Daniel Paris, Henrik Skov, Andreas Massling, Aurélien Dommergue, Mikhail Arshinov, Denis Davydov, Boris Belan, Tuukka Petäjä. (2022). Arctic observations and sustainable development goals – Contributions and examples from ERA-PLANET iCUPE data (Vol. 132).
Abstract: Integrative and Comprehensive Understanding on Polar Environments (iCUPE) project developed 24 novel datasets utilizing in-situ observational capacities within the Arctic or remote sensing observations from ground or from space. The datasets covered atmospheric, cryospheric, marine, and terrestrial domains. This paper connects the iCUPE datasets to United Nations’ Sustainable Development Goals and showcases the use of selected datasets as knowledge provision services for policy- and decision-making actions. Inclusion of indigenous and societal knowledge into the data processing pipelines enables a feedback mechanism that facilitates data driven public services.
Keywords: Arctic data Data driven public services In-situ Mercury Remote sensing Sustainable development
Programme: 1028
|
|
|
Estelle Cateau, Antoine Leclerc, Noémie Cartier, Isabel Valsecchi, Éric Bailly, Ronan Le Senechal, Margaux Becerra, Brice Le Gallou, Rose-Anne Lavergne, Adélaïde Chesnay, Jean-Patrice Robin, Carolyn Cray, Nicolas Goddard, Milan Thorel, Jacques Guillot, Baptiste Mulot, Guillaume Desoubeaux. (2022). Aspergillosis in a colony of Humboldt penguins (Spheniscus humboldti) under managed care: a clinical and environmental investigation in a French zoological park (Vol. 60).
Abstract: Aspergillosis is pervasive in bird populations, especially those under human care. Its management can be critically impacted by exposure to high levels of conidia and by resistance to azole drugs. The fungal contamination in the environment of a Humboldt penguin (Spheniscus humboldti) group, housed in a French zoological park next to numerous large crop fields, was assessed through three serial sessions of surface sampling in nests, in 2018–20: all isolates were counted and characterized by sequencing. When identified as Aspergillus fumigatus, they were systematically screened for resistance mutations in the cyp51A gene and tested for minimal inhibitory concentrations (MICs) determination. At the same time, the clinical incidence of aspergillosis was evaluated in the penguin population by the means of systematic necropsy and mycological investigations. A microsatellite-based analysis tracked the circulation of A. fumigatus strains. Environmental investigations highlighted the substantial increase of the fungal load during the summer season (>12-fold vs. the other timepoints) and a large overrepresentation of species belonging to the Aspergillus section Fumigati, ranging from 22.7 to 94.6% relative prevalence. Only one cryptic species was detected (A. nishimurae), and one isolate exhibited G138S resistance mutation with elevated MICs. The overall incidence of aspergillosis was measured at ∼3.4% case-years, and mostly in juveniles. The analysis of microsatellite polymorphism revealed a high level of genetic diversity among A. fumigatus clinical isolates. In contrast, one environmental strain appeared largely overrepresented during the summer sampling session. In all, the rural location of the zoo did not influence the emergence of resistant strains.- The incidence of aspergillosis in the penguin population of a French zoo was found elevated, mostly in juveniles.- The fungal contamination was high in the surrounding environment, especially at the end of summer.- Globally, a great level of genetic diversity was observed, except for one clonal strain.
Programme: 119
|
|
|
Yves Cherel, Antoine Carrouée. (2022). Assessing marine ecosystem complexity: isotopic integration of the trophic structure of seabird communities from the Southern Ocean (Vol. 694).
Abstract: Understanding the processes structuring communities is a fundamental goal in ecology and conservation biology. Seabirds are commonly used as sentinels of marine ecosystems, but there is a lack of quantitative information providing a synoptic view of their community structure and of its underlying mechanisms. We used stable isotope analysis of chick feathers to investigate the structure of 2 communities that are representative of the subantarctic (Kerguelen) and Antarctic (Adélie Land) seabird diversity. Total area of the convex hull (a measure of the total δ13C-δ15N niche space) was 8.4-fold higher at the Kerguelen Islands than in Adélie Land, a consequence of the higher seabird diversity at the former locality. Kerguelen seabirds grouped into 2 clusters of oceanic and inshore species, with the latter group not represented in Adélie Land. Communities are primarily structured by the availability of foraging habitats (δ13C) and then of trophic resources (δ15N), with body size being a major driving force of trophic position. Ecological characteristics are more important than phylogeny to shape seabird isotopic niche breadth (standard ellipse area corrected for small sample size, SEAc), with no significant differences between Sphenisciformes, Procellariiformes, and Charadriiformes. By contrast, SEAc varies according to foraging guilds, diet, and a specialist-generalist gradient, with ubiquitous seabirds having a 10-fold larger mean SEAc than pelagic divers. This study sets a baseline against which the effects of long-term environmental changes on seabird community structure can be studied across years and conditions, and provides a relevant starting point for the investigation into the effect of climate change on Southern Ocean ecosystems.
Keywords: Antarctica Body size Habitat Penguins Procellariiformes Stable isotopes Trophic position
Programme: 109
|
|
|
Mark Andrew Hindell, Clive Reginald McMahon, Christophe Guinet, Rob Harcourt, Ian David Jonsen, Ben Raymond, Dale Maschette. (2022). Assessing the potential for resource competition between the Kerguelen Plateau fisheries and southern elephant seals (Vol. 9). Bachelor's thesis, , .
Abstract: Indirect ecological interactions such as competition for resources between fisheries and marine predators have often been proposed but can be difficult to demonstrate empirically. The Kerguelen Plateau in the Southern Indian Ocean supports fisheries for both Patagonian toothfish and mackerel icefish and is also an important foraging ground for several avian and mammalian predators, including the southern elephant seal. We quantified the spatio-temporal use of the plateau by southern elephant seals and found that males and females spent 30% of their time on the plateau within the commonly used fishing grounds, indicating the possibility of competition for resources there. We then contrasted the seals’ use of two habitat types, the benthos (where interactions with the long-line fisheries are most likely) and the epi-pelagic zone. The likelihood of feeding on the benthos declined as ocean depth increased and was also less likely at night. Males were also more likely to feed on the benthos than females. The sub-adult male seals consumed an estimated 6,814 – 14,848 tons of high energy content prey (including toothfish) and females 7,085 – 18,037 tons from the plateau during the post-molt winter months. For males this represented 79.6 – 173.4% of the mean annual catch by the Kerguelen fishery compared to 82.8 – 210.7% for adult females. When considering the seals consumption of fish from the benthos within the fishing grounds these estimates decreased to 3.6 – 15.1% of the fishery’s total annual catch for females and 7.8 – 19.1% for males. While this further indicates the possibility of indirect ecological interactions (with the fishery taking more fish than the seals), the lack of detailed diet information for the seals precludes us from establishing the degree or nature of the possible interactions because the importance of toothfish and icefish in the diet of the seals is unknown. However, the unique life history and highly polygynous nature of this species, and the lack of evidence of a measurable effect on either the seal’s population growth rates or the catch per unit of the fishery, suggest that any indirect ecological interactions are not of sufficient magnitude to affect either the seal population or the fishery.
Programme: 109,1201
|
|
|
Christoph Kittel, Xavier Fettweis, Ghislain Picard, Noel Gourmelen. (2022). Assimilation of satellite-derived melt extent increases melt simulated by MAR over the Amundsen sector (West Antarctica) (Vol. 78).
Abstract: La fonte de surface sur les plateformes de glace en Antarctique est l'une des plus grandes incertitudes liées à l'augmentation du niveau de la mer pendant le 21e siècle. Cependant, les modèles climatiques actuels peinent encore à la représenter avec précision, ce qui limite la compréhension des processus expliquant sa variabilité spatiale et temporelle et ses conséquences sur la stabilité de l’inlandsis de l’Antarctique. Les progrès récents de surveillance de la Terre grâce aux satellites ont permis de créer de nouvelles estimations de l'étendue de la fonte en Antarctique. Ceux-ci peuvent détecter si et où la fonte se produit, tandis que la quantité d'eau de fonte produite ne peut par contre être déduite que de simulations climatiques. Afin de combiner les avantages des deux outils, nous présentons de nouvelles estimations de la fonte basées sur un modèle climatique régional assimilant l'étendue de la fonte dérivée des satellites. Cela améliore la comparaison entre les estimations du modèle et du satellite, ouvrant ainsi la voie à une ré-estimation de la quantité de fonte produite chaque année à la surface de l'ensemble de l'inlandsis de l’Antarctique.
Programme: 1110
|
|
|
Karine Delord, Yves Cherel, Amédée Roy, Paco Bustamante, Kerrie M. Swadling, Henri Weimerskirch, Charles-André Bost, Christophe Barbraud. (2022). At-sea behavioural ecology of the endangered MacGillivray’s prion from Saint Paul Island: combining tracking and stable isotopes (Vol. 697). Bachelor's thesis, , .
Abstract: Seabirds play important roles as marine ecosystem sentinels. Studying their at-sea ecology is essential for understanding how environmental variability affects their populations. However, the at-sea ecology of small-sized temperate seabirds remains poorly studied. We explored the at-sea ecology of the Critically Endangered MacGillivray’s prion Pachyptila macgillivrayi breeding on the subtropical Saint Paul Island. Using global location sensor loggers and stable isotope analysis, we investigated movements, migratory strategies, at-sea activity and moulting period, and characterized the isotopic niche of tracked individuals. During incubation, MacGillivray’s prions remained in temperate waters north of the Subtropical Front, possibly feeding on prey caught in cold eddies. During the inter-breeding period, individuals wintered almost equally to the north and south of the Subtropical Front in 2 distinct sectors (Tasman Sea and Southwest Indian Ridge). Daily activity varied seasonally, and individuals overwintering in the Tasman Sea spent more time flying at night when moonlight intensity was high. Moulting occurred after the breeding period and lasted longer compared to other prion species. Isotopic data suggest a higher dietary proportion of low trophic-level prey for MacGillivray’s prions than for Antarctic and slender-billed prions, highlighting trophic segregation in relation to bill width. Our study provides new evidence to understand the suite of adaptations allowing the abundant prion species to coexist by feeding on prey of different sizes. Contrary to the majority of seabird species, MacGillivray’s prions from Saint Paul Island exhibited 2 migratory tactics with associated differences in at-sea activity, leading to questions about the origin of these differences.
Keywords: Activity pattern At-sea distribution Bill width Geolocation GPS Pachyptila macgillivrayi Seabirds Southern Indian Ocean Trophic position
Programme: 109,394
|
|
|
Jordi Diaz. (2022). Atmosphere-solid earth coupling signals generated by the 15 January 2022 Hunga-Tonga eruption (Vol. 3).
Abstract: The January 15th 2022 eruption of the Hunga-Tonga volcano was associated to one of the highest energy volcanic explosions of the past few decades. Here we present a compilation of data from global seismic networks to explore three main topics: the time evolution of the eruption, the propagation of the atmospheric waves around the Earth and the low-frequency, long-lasting seismic signals worldwide after the main event. We find that the eruption started around 04:00, included two large explosions at 05:30 and 08:25 and produced atmospheric waves which circled the Earth more than two times during a time span of 3.5 days and were detected seismically. We also identify very low frequency signals, detected over several hours, which we interpret as resulting from the excitation of Earth normal modes. To our knowledge, there are no previous examples of atmospheric-solid Earth coupling over such a long time interval and only two examples of normal mode excitation following volcanic eruptions.
Keywords: Geophysics Natural hazards Seismology Volcanology
Programme: 133
|
|
|
Kyriakos Balidakis, Roman Sulzbach, Linus Shihora, Christoph Dahle, Robert Dill, Henryk Dobslaw. (2022). Atmospheric Contributions to Global Ocean Tides for Satellite Gravimetry (Vol. 14).
Abstract: To mitigate temporal aliasing effects in monthly mean global gravity fields from the GRACE and GRACE-FO satellite tandem missions, both tidal and non-tidal background models describing high-frequency mass variability in atmosphere and oceans are needed. To quantify tides in the atmosphere, we exploit the higher spatial (31 km) and temporal (1 hr) resolution provided by the latest atmospheric ECMWF reanalysis, ERA5. The oceanic response to atmospheric tides is subsequently modeled with the general ocean circulation model MPIOM (in a recently revised TP10L40 configuration that includes the feedback of self-attraction and loading to the momentum equations and has an improved bathymetry around Antarctica) as well as the shallow water model TiME (employing a much higher spatial resolution and more elaborate tidal dissipation than MPIOM). Both ocean models consider jointly the effects of atmospheric pressure variations and surface wind stress. We present the characteristics of 16 waves beating at frequencies in the 1–6 cpd band and find that TiME typically outperforms the corresponding results from MPIOM and also FES2014b as measured from comparisons with tide gauge data. Moreover, we note improvements in GRACE-FO laser ranging interferometer range-acceleration pre-fit residuals when employing the ocean tide solutions from TiME, in particular, for the S1 spectral line with most notable improvements around Australia, India, and the northern part of South America.
Keywords: atmospheric forcing atmospheric tides de-aliasing ERA5 GRACE-FO ocean tides
Programme: 688
|
|