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Article Reference Possible effects of global environmental changes on Antarctic benthos : a synthesis across five major taxa
Because of the unique conditions that exist around the Antarctic continent, Southern Ocean (SO) ecosystems are very susceptible to the growing impact of global climate change and other anthropogenic influences. Consequently, there is an urgent need to understand how SO marine life will cope with expected future changes in the environment. Studies of Antarctic organisms have shown that individual species and higher taxa display different degrees of sensitivity to environmental shifts, making it difficult to predict overall community or ecosystem responses. This emphasizes the need for an improved understanding of the Antarctic benthic ecosystem response to global climate change using a multitaxon approach with consideration of different levels of biological organization. Here, we provide a synthesis of the ability of five important Antarctic benthic taxa (Foraminifera, Nematoda, Amphipoda, Isopoda, and Echinoidea) to cope with changes in the environment (temperature, pH, ice cover, ice scouring, food quantity, and quality) that are linked to climatic changes. Responses from individual to the taxon-specific community level to these drivers will vary with taxon but will include local species extinctions, invasions of warmer-water species, shifts in diversity, dominance, and trophic group composition, all with likely consequences for ecosystem functioning. Limitations in our current knowledge and understanding of climate change effects on the different levels are discussed.
Located in Library / RBINS Staff Publications
Article Reference The Parvidrilidae – a diversified groundwater family: description of six new species from southern Europe, and clues for its phylogenetic position within Clitellata (Annelida)
The Parvidrilidae Erséus, 1999 constitute the most recently described family of oligochaete microdriles. Prior to this study, Parvidrilus strayeri Erséus, 1999, and Parvidrilus spelaeus Martínez-Ansemil, Sambugar & Giani, 2002, found in groundwaters of the USA (Alabama) and Europe (Slovenia and Italy), respectively, were the only two species in this family. In this paper, six new species – Parvidrilus camachoi, Parvidrilus gianii, Parvidrilus jugeti, Parvidrilus meyssonnieri, Parvidrilus stochi, and Parvidrilus tomasini – and Parvidrilus gineti (Juget, 1959) comb. nov. are added to the family. With all species being stygobiont, the Parvidrilidae is unique in being the only family of oligochaetes worldwide comprising taxa that are restricted to groundwater habitats. Parvidrilids are exceedingly small worms whose principal morphological characteristics are the presence of hair setae in ventral bundles, the markedly posterior position of setae within the segments, the presence of mid-dorsal glandular pouches in mesosomial segments, the lateral development of the clitellum, the presence of a single male pore in segment XII, and the presence (or absence) of a single spermatheca. The phylogenetic relationships of the Parvidrilidae within the Clitellata were investigated using the nuclear 18S rRNA gene, and the most representative and taxonomically balanced data set of clitellate families available to date. The data were analysed by parsimony, maximum likelihood, and Bayesian inference. Irrespective of the method used, Parvidrilidae were placed far from Capilloventridae, one family once suggested to be closely related to parvidrilids. Although closer to Enchytraeidae than Phreodrilidae, two other suggested putative sister families, the exact position of Parvidrilidae within Clitellata still remained uncertain in the absence of branch support. The examination of reproductive structures, together with the similarity of other important anatomical traits of the new species herein described, reinforced the idea that phreodrilids were the best candidate to be the sister group to parvidrilids on morphological grounds. A fragment of the mitochondrial cytochrome oxidase I gene, used as a barcode, also genetically characterized a few Parvidrilus species. The observation that two species diverge from each other by high genetic distances, even though their type localities are more or less only 100 km apart, is interpreted in the context of low dispersal abilities of inhabitants of the subterranean aquatic ecosystem, and habitat heterogeneity. The Parvidrilidae appear to be a diversified, Holarctic, and probably widely distributed family in groundwater, but very often overlooked because of the small size and external similarity with the polychaete family Aeolosomatidae of its members.
Located in Library / RBINS Staff Publications
Article Reference Incongruence between molecular phylogeny and morphological classification in amphipod crustaceans: A case study of Antarctic lysianassoids
In Antarctic waters, the superfamily Lysianassoidea is one of the most important amphipod groups both in terms of species number and abundance. Dominant members of this superfamily are species of the orchomenid complex, found throughout the Southern Ocean. This study presents the first molecular phylogenetic analysis based on a representative subset of the Antarctic species belonging to different orchomenid genera and hence provides a framework for a systematic revision of these taxa. The current classification of the orchomenid genera is mainly based on mouthpart morphology. The validity of these morphological characters was assessed by resolving phylogenetic relationships using nuclear 28S rRNA and mitochondrial cytochrome oxidase subunit I sequences. The molecular data rejected most of the previously proposed taxonomic subdivisions within this complex. The genera Abyssorchomene and Orchomenella as well as the subgenus Orchomenopsis appeared to be non-monophyletic. This implies that the supposed diagnostic characters are likely a result of convergent evolution. Further, our results indicated the necessity of a revision of the family-level systematics.
Located in Library / RBINS Staff Publications
Article Reference Fifteen microsatellite loci for the decollate snail, Rumina decollata.
We characterized 15 microsatellite loci from the decollate snail, Rumina decollata. Loci were screened in 21 individuals and several individuals of the congener Rumina saharica. There was ample allelic diversity (6–12 alleles per locus) but observed heterozygosity values were extremely low (0–0.421). This was expected given the high self-fertilization rate in this species. Ten of the 15 loci were successfully amplified in R. saharica. These loci provide tools for examining the population genetics and taxomomic boundaries in R. decollata and its allies.
Located in Library / RBINS Staff Publications
Article Reference Harpacticoid copepod colonization of coral fragments in a tropical reef lagoon (Zanzibar, Tanzania)
Colonization experiments were conducted in a tropical lagoon (Zanzibar Island, off the coast of Tanzania) to investigate the temporal dynamics and mode of colonization of the harpacticoid copepods community on dead coral fragments. There was fast colonization of the coral fragments attaining a substantial diversity after only two days. The ability to colonize dead coral fragments is thought to be related to the morphology and life style of different harpacticoid species. Phytal taxa (e.g. Tisbidae) were fast colonizers, reaching high abundances during the initial colonization phase. Sediment-associated and eurytopic taxa (e.g. Ameiridae, Miraciidae and Ectinosomatidae) showed lower colonization rates and became the dominant group during the later colonization phase. Most species are able to colonize the coral fragments through the water column. However, colonization along the substrate surface is also considered to be an important colonization mode, especially for sediment-associated taxa, which showed lower colonization rates when migration through the sediment was hindered.
Located in Library / RBINS Staff Publications
Article Reference Dispersal and gene flow in free-living marine nematodes
Located in Library / RBINS Staff Publications
Article Reference Identifying insects with incomplete DNA barcode libraries, African fruit flies (Diptera: Tephritidae) as a test case.
Located in Library / RBINS Staff Publications
Article Reference Darwininitium – a new fully pseudosigmurethrous orthuretran genus from Nepal (Gastropoda, Pulmonata, Cerastidae)
Located in Library / RBINS Staff Publications
Article Reference Redéfinition des unités structurales du front varisque utilisées dans le cadre de la nouvelle Carte géologique de Wallonie (Belgique).
The new geological map of Wallonia permits to obtain a more global view of the tectonic organization of the Palaeozoic terrains around the Variscan Front in southern Belgium. This zone oriented WSW-ENE and passing south of an axis Charleroi-Namur, was firstly highlighted by the coal mining works, but has been significantly documented notably through deep boreholes and seismic profiles. A coherent structural sketch of the Variscan Front is proposed for its entire longitudinal course, where the following structural units are distinguished, from north to south: the Brabant Massif and the base of the cover unaffected by the Variscan orogeny, the Brabant Parautochthon, the Haine-Sambre-Meuse Overturned Thrust sheets (HSM-OTS) and the Ardenne Allochthon. Undeformed terrains during Variscan event constitute the northern border of the Variscan Front. The Brabant Parautochthon includes Devono-Carboniferous terrains, which are folded and faulted. The HSM-OTS are formed by the superposition of several sheets (e.g. La Tombe sheet), which are supported by various thrust faults (e.g. Masse fault). The Ardenne Allochthon, which has been displaced during the Variscan orogeny, rests on the Brabant Parautochthon and the HSM-OTS through a faulted zone, which is locally known as the Midi Fault.
Located in Library / RBINS Staff Publications
Article Reference Woody climbing plants influence the structure of the mountain forest in the Kahuzi-Biega National Park, DR Congo
In the mountain forests of the Kahuzi-Biega National Park (KBNP), in the Democratic Republic of Congo, where Sericostachys scandens, a woody climbing plant in the Amaranthaceae family, is expanding, trees appear to be negatively affected by this liana. In order to contribute to the understanding of the links between the expansion of the liana and the decline of its hosts, we compared the density and the species richness of the trees of dbh (diameter at breast height) ≥5 cm from the plots invaded by S. scandens with those from parcels that are still free from the invasion. The results of the paired unilateral t test applied to the overall sample showed that the tree density is very low in the plots dominated by the liana (p < 0.01), but that species richness is not affected (p > 0.05). In the class with diameter [10–30 cm], the lowest density of trees corresponds to the plots colonized by S. scandens, compared to the places where the liana is not abundant (p < 0.01). Further, the density of trees is significantly lower (p < 0.05) in the classes with diameters [5–10 cm] and ≥30 cm, in plots dominated by S. scandens. In conclusion, the emergence of the liana S. scandens has a negative effect on the density of the trees in the mountain forest of the KBNP. Résumé Dans les forêts de montagne du Parc National Kahuzi-Biega (PNKB), en République Démocratique du Congo, où Sericostachys scandens, plante ligneuse grimpante de la famille des Amaranthaceae, est en plein essor, son feuillage dense encombre les arbres et les étouffe. En vue de contribuer à élucider les liens entre l’expansion de cette liane et le déclin de ses hôtes, la densité et la richesse spécifique des arbres ayant un dbh («diameter at breast height», c’est –à –dire le diamètre mesuré à 1, 30 m au-dessus du sol) ≥5 cm des parcelles envahies par S. scandens ont été comparées à celles des endroits qui ne le sont pas. Le résultat du test t unilatéral par paires appliqué à l’échantillon global a montré que la densité des arbres est très basse dans les parcelles dominées par la liane (p < 0.01), mais qu’il n’y a pas d’effet sur la richesse spécifique (p > 0.05). Dans la classe de diamètre [10–30 cm[, une densité plus faible a été trouvée dans les parcelles colonisées par la liane par rapport à celles où elle n’abonde pas (p < 0.01). En plus, la densité des arbres est significativement basse (p < 0.05) dans les classes de diamètres [5–10 cm[et ≥30 cm dans les parcelles dominées par la liane. L’expansion de la liane S. scandens a donc un effet négatif sur la densité des arbres en forêt de montagne au PNKB.
Located in Library / RBINS Staff Publications