Biological, Earth and Environmental Sciences - Journal Articles

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    Stable isotopes suggest fine-scale sexual segregation in an isolated, endangered sperm whale population
    (Inter Research, 2020-11-12) Pirotta, Enrico; Vighi, Morgana; Brotons, José María; Dillane, Eileen; Cerdà, Margalida; Rendell, Luke; National Geographic Society
    Sexual segregation is common among marine mammals, leading to intraspecific differences in diet, diving behaviour, home range size and even latitudinal distribution and migratory patterns. Sperm whales Physeter macrocephalus present one of the most extreme examples of sexual dimorphism both in size and social structure, with males and females segregating at different latitudes across most of their range, but the underlying ecological drivers remain unclear. Studying fine-scale dietary and habitat differences where the sexes occur in sympatry could therefore provide insights into the mechanisms underpinning their large-scale segregation. In this study, we analysed the carbon and nitrogen stable isotope values in the skin of males and females from an isolated, endangered population inhabiting the Mediterranean Sea, sampled in a region where the sexes occur and feed regularly in the summer months but show subtle differences in habitat preference. We found marked differences in both carbon and nitrogen isotopic values between the sexes, indicating that they could be targeting prey items in different trophic levels and habitats. Combined with the evidence from habitat modelling studies, our results suggest that female and male sperm whales segregate even in the latitudinally restricted Mediterranean population, at a much smaller scale. This sympatric, fine-scale sexual segregation suggests that reduction of competition may have been a key factor in the evolution of the social structure and large-scale latitudinal segregation of this species.
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    More than one million barriers fragment Europe’s rivers
    (Springer Nature Ltd., 2020-12-16) Belletti, Barbara; Garcia de Leaniz, Carlos; Jones, Joshua; Bizzi, Simone; Börger, Luca; Segura, Gilles; Castelletti, Andrea; van de Bund, Wouter; Aarestrup, Kim; Barry, James; Belka, Kamila; Berkhuysen, Arjan; Birnie-Gauvin, Kim; Bussettini, Martina; Carolli, Mauro; Consuegra, Sofia; Dopico, Eduardo; Feierfeil, Tim; Fernández, Sara; Fernandez Garrido, Pao; Garcia-Vazquez, Eva; Garrido, Sara; Giannico, Guillermo; Gough, Peter; Jepsen, Niels; Jones, Peter E.; Kemp, Paul; Kerr, Jim; King, James; Łapińska, Małgorzata; Lázaro, Gloria; Lucas, Martyn C.; Marcello, Lucio; Martin, Patrick; McGinnity, Philip; O’Hanley, Jesse; del Amo, Rosa Olivo; Parasiewicz, Piotr; Pusch, Martin; Rincon, Gonzalo; Rodriguez, Cesar; Royte, Joshua; Schneider, Claus Till; Tummers, Jeroen S.; Vallesi, Sergio; Vowles, Andrew; Verspoor, Eric; Wanningen, Herman; Wantzen, Karl M.; Wildman, Laura; Zalewski, Maciej; Horizon 2020; Université de Lyon
    Rivers support some of Earth’s richest biodiversity and provide essential ecosystem services to society, but they are often fragmented by barriers to free flow. In Europe, attempts to quantify river connectivity have been hampered by the absence of a harmonized barrier database. Here we show that there are at least 1.2 million instream barriers in 36 European countries (with a mean density of 0.74 barriers per kilometre), 68 per cent of which are structures less than two metres in height that are often overlooked. Standardized walkover surveys along 2,715 kilometres of stream length for 147 rivers indicate that existing records underestimate barrier numbers by about 61 per cent. The highest barrier densities occur in the heavily modified rivers of central Europe and the lowest barrier densities occur in the most remote, sparsely populated alpine areas. Across Europe, the main predictors of barrier density are agricultural pressure, density of river-road crossings, extent of surface water and elevation. Relatively unfragmented rivers are still found in the Balkans, the Baltic states and parts of Scandinavia and southern Europe, but these require urgent protection from proposed dam developments. Our findings could inform the implementation of the EU Biodiversity Strategy, which aims to reconnect 25,000 kilometres of Europe’s rivers by 2030, but achieving this will require a paradigm shift in river restoration that recognizes the widespread impacts caused by small barriers.
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    Base metal sulphide geochemistry of southern African mantle eclogites (Roberts Victor): Implications for cratonic mafic magmatism and metallogenesis
    (Elsevier B.V., 2020-12-25) Hughes, Hannah S. R.; Compton-Jones, Charlie; McDonald, Iain; Kiseeva, Ekaterina S.; Kamenetsky, Vadim S.; Rollinson, Gavyn; Coggon, Judith A.; Kinnaird, Judith A.; Bybee, Grant M.; Natural Environment Research Council; Russian Science Foundation
    Platinum-group elements (PGE) display a chalcophile behaviour and are largely hosted by base metal sulphide (BMS) minerals in the mantle. During partial melting of the mantle, BMS release their metal budget into the magma generated. The fertility of magma sources is a key component of the mineralisation potential of large igneous provinces (LIP) and the origin of orthomagmatic sulphide deposits hosted in cratonic mafic magmatic systems. Fertility of mantle-derived magma is therefore predicated on our understanding of the abundance of metals, such as the PGE, in the asthenospheric and lithospheric mantle. Estimations of the abundance of chalcophile elements in the upper mantle are based on observations from mantle xenoliths and BMS inclusions in diamonds. Whilst previous assessments exist for the BMS composition and chalcophile element budget of peridotitic mantle, relatively few analyses have been published for eclogitic mantle. Here, we present sulphide petrography and an extensive in situ dataset of BMS trace element compositions from Roberts Victor eclogite xenoliths (Kaapvaal Craton, South Africa). The BMS are dominated by pyrite-chalcopyrite-pentlandite (± pyrrhotite) assemblages with S/Se ratios ranging 1200 to 36,840 (with 87% of analyses having S/Se <10,000. Total PGE abundance in BMS range from 0.17 to 223 ppm. We recognise four end-member compositions (types i to iv), distinguished by total PGE abundance and Pt/Pd and Au/Pd ratios. The majority of BMS have low PGE abundances (< 10 ppm) but Type iv BMS have the highest concentration of PGE recorded in eclogites so far (> 100 ppm) and are characteristically enriched in Os, Ir, Ru and Rh. Nano- and micron-scale Pd-Pt antimonide, telluride and arsenide platinum-group minerals (PGM) are observed spatially associated with BMS. We suggest that the predominance of pyrite in the xenoliths reflects the process of eclogitisation and that the trace element composition of the eclogite BMS was inherited from oceanic crustal protoliths of the eclogites, introduced into the SCLM via ancient subduction during formation of the Colesberg Magnetic Lineament c. 2.9 Ga and the cratonisation of the Kaapvaal Craton. Crucially, we demonstrate that the PGE budget of eclogitic SCLM may be substantially higher than previously reported, akin to peridotitic compositions, with significant implications for the PGE fertility of cratonic mafic magmatism and metallogenesis. We quantitatively assess these implications by modelling the chalcophile geochemistry of an eclogitic melt component in parental magmas of the mafic Rustenburg Layered Suite of the Bushveld Complex.
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    What do the terms resistance, tolerance, and resilience mean in the case of Ostrea edulis infected by the haplosporidian parasite Bonamia ostreae
    (Elsevier B.V., 2021-04-29) Holbrook, Zoë; Bean, Tim P.; Lynch, Sharon A.; Hauton, Chris; Leverhulme Trust; Biotechnology and Biological Sciences Research Council; Natural Environment Research Council; Scottish Aquaculture Innovation Centre; European Regional Development Fund
    The decline of the European flat oyster Ostrea edulis represents a loss to European coastal economies both in terms of food security and by affecting the Good Environmental Status of the marine environment as set out by the European Council’s Marine Strategy Framework Directive (2008/56/EC). Restoration of O. edulis habitat is being widely discussed across Europe, addressing key challenges such as the devastating impact of the haplosporidian parasite Bonamia ostreae. The use of resistant, tolerant, or resilient oysters as restoration broodstock has been proposed by restoration practitioners, but the definitions and implications of these superficially familiar terms have yet to be defined and agreed by all stakeholders. This opinion piece considers the challenges of differentiating Bonamia resistance, tolerance, and resilience; challenges which impede the adoption of robust definitions. We argue that, disease-resistance is reduced susceptibility to infection by the parasite, or active suppression of the parasites ability to multiply and proliferate. Disease-tolerance is the retention of fitness and an ability to neutralise the virulence of the parasite. Disease-resilience is the ability to recover from illness and, at population level, tolerance could be interpreted as resilience. We concede that further work is required to resolve practical uncertainty in applying these definitions, and argue for a collaboration of experts to achieve consensus. Failure to act now might result in the future dispersal of this disease into new locations and populations, because robust definitions are important components of regulatory mechanisms that underpin marine management.
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    Home range of a long-distance migrant, the Greenland Barnacle Goose Branta leucopsis, throughout the annual cycle
    (Taylor & Francis Group, 2023-04-03) Doyle, Susan; Cabot, David; Griffin, Larry; Kane, Adam; Colhoun, Kendrew; Redmond, Courtney; Walsh, Alyn; McMahon, Barry J.; Irish Research Council; National Parks and Wildlife Service; Bryan Guinness Charitable Trust
    Capsule: Home range area and foraging distance of the Greenland Barnacle Goose Branta leucopsis, a long-distance migrant were calculated and activity patterns were described. Aims: To understand the use of space by Barnacle Geese throughout the annual cycle, and to inform effective wildlife management and conservation planning. Methods: Tracking data from 29 annual cycles from 18 individual Barnacle Geese were analysed to estimate overall (80–99% utilization distribution; UD) and core (50% UD) home ranges using a Brownian bridge kernel method. Maximum and core foraging distance were then estimated from 80–99% UD and 50% UD, respectively. Finally, daily activity patterns, including the location of roosts and foraging sites, were described, along with variability in home range among seasons and between males and females, and spatial and temporal repeatability. Results: Overall home range area was approximately 14 km2 in winter, 9.5 km2 in spring, 7 km2 in the nesting period, 43 km2 in the post-nesting period, and 48 km2 in autumn. However, the core area used by the birds was substantially smaller: mean core home range area was approximately 1.5 km2 in winter, 1 km2 in spring, 2 km2 in the nesting period, 7 km2 in the post-nesting period, and 12 km2 in autumn. Maximum foraging distances were approximately 7 km in winter, 5 km in spring, 3.5 km in the nesting period, 15.5 km in the post-nesting period, and 32.5 km in autumn. Core foraging distances were approximately 5.5 km in winter, 3 km in spring, 1 km in the nesting period, 8.5 km in the post-nesting period, and 19.5 km in autumn. Conclusion: Although our study focuses on the movements of Barnacle Geese, such data can be used to inform a range of pure and applied ornithological issues, including resource partitioning, human-wildlife conflicts, and the spread of zoonotic disease.