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  • Alstrom, P., et al. (författare)
  • Complete species-level phylogeny of the leaf warbler (Aves: Phylloscopidae) radiation
  • 2018
  • Ingår i: Molecular Phylogenetics and Evolution. - 1055-7903. ; 126, s. 141-152
  • Tidskriftsartikel (refereegranskat)abstract
    • The leaf warbler radiation (Aves: Phylloscopidae) has undergone a c. 50% increase in the number of recognised species over the last three decades, mainly as a result of analyses of vocalisations and DNA. Using a multilocus dataset for all of the species in this family, and multispecies coalescent-based as well as concatenation methods, we provide the first complete species-level phylogeny for this important group, as well as an estimate of the timing of diversification. The most recent common ancestor for the family was dated at 11.7 million years ago (mya) (95% highest posterior density 9.8-13.7 mya), and divergence times between sister species ranged from 0.5 mya (0.3-0.8 mya) to 6.1 mya (4.8-7.5 mya). Based on our results, we support synonymising Seicercus with Phylloscopus, which results in a monogeneric Phylloscopidae. We discuss the pros and cons of this treatment, and we argue against proliferation of taxonomic names, and conclude that a large monogeneric Phylloscopidae leads to the fewest taxonomic changes compared to traditional classifications. We briefly discuss morphological evolution in the light of the phylogeny. The time calibrated phylogeny is a major improvement compared to previous studies based on a smaller number of species and loci and can provide a basis for future studies of other aspects of phylloscopid evolution.
  • Alstrom, P., et al. (författare)
  • Comprehensive molecular phylogeny of the grassbirds and allies (Locustellidae) reveals extensive non-monophyly of traditional genera, and a proposal for a new classification
  • 2018
  • Ingår i: Molecular Phylogenetics and Evolution. - 1055-7903. ; 127, s. 367-375
  • Tidskriftsartikel (refereegranskat)abstract
    • The widespread Old World avian family Locustellidae (‘grassbirds and allies’) comprises 62 extant species in 11 genera. In the present study, we used one mitochondrial and, for most species, four nuclear loci to infer the phylogeny of this family. We analysed 59 species, including the five previously unsampled genera plus two genera that had not before been analysed in a densely sampled dataset. This study revealed extensive disagreement with current taxonomy; the genera Bradypterus, Locustella, Megalurus, Megalurulus and Schoenicola were all found to be non-monophyletic. Non-monophyly was particularly pronounced for Megalurus, which was widely scattered across the tree. Three of the five monotypic genera (Amphilais, Buettikoferella and Malia) were nested within other genera; one monotypic genus (Chaetornis) formed a clade with one of the two species of Schoenicola; whereas the position of the fifth monotypic genus (Elaphrornis) was unresolved. Robsonius was confirmed as sister to the other genera. We propose a phylogenetically informed revision of genus-level taxonomy, including one new generic name. Finally, we highlight several non-monophyletic species complexes and deep intra-species divergences that point to conflict in taxonomy and suggest an underestimation of current species diversity in this group.
  • Alstrom, Per, et al. (författare)
  • Morphological, vocal and genetic divergence in the Cettia acanthizoides complex (Aves: Cettiidae)
  • 2007
  • Ingår i: Zoological Journal of the Linnean Society. - 0024-4082. ; 149:3, s. 437-452
  • Tidskriftsartikel (refereegranskat)abstract
    • We used morphological, vocal and molecular (one mitochondrial and two nuclear loci) data to re-evaluate the taxonomic status of the taxa acanthizoides, concolor, and brunnescens in the Cettia acanthizoides (J. Verreaux, 1871) complex. We conclude that all three are valid taxa, and that acanthizoides of China and concolor of Taiwan are best treated as conspecific, whereas brunnescens of the Himalayas is better considered as a separate species. The degree of morphological, vocal, and genetic differentiation is variably congruent among all taxa; the recently separated acanthizoides and concolor differ slightly in plumage and structure but are indistinguishable in vocalizations, whereas the earlier diverged brunnescens and acanthizoides/concolor differ only slightly more in morphology but to a much greater degree in vocalizations. We stress the essential nature of taxonomic revisions as a prerequisite for the biodiversity estimates required for conservation planning.
  • Alström, Per, et al. (författare)
  • Dramatic niche shifts and morphological change in two insular bird species
  • 2015
  • Ingår i: Royal Society Open Science. - 2054-5703. ; 2
  • Tidskriftsartikel (refereegranskat)abstract
    • Colonizations of islands are often associated with rapid morphological divergence. We present two previously unrecognized cases of dramatic morphological change and niche shifts in connection with colonization of tropical forest-covered islands. These evolutionary changes have concealed the fact that the passerine birds madanga, Madanga ruficollis, from Buru, Indonesia, and São Tomé shorttail, Amaurocichla bocagii, from São Tomé, Gulf of Guinea, are forest-adapted members of the family Motacillidae (pipits and wagtails). We show that Madanga has diverged mainly in plumage, which may be the result of selection for improved camouflage in its new arboreal niche, while selection pressures for other morphological changes have probably been weak owing to preadaptations for the novel niche. By contrast, we suggest that Amaurocichla's niche change has led to divergence in both structure and plumage.
  • Andersson, Stefan S., et al. (författare)
  • Apatite as a tracer of the source, chemistry and evolution of ore-forming fluids : The case of the Olserum-Djupedal REE-phosphate mineralisation, SE Sweden
  • 2019
  • Ingår i: Geochimica et Cosmochimica Acta. - PERGAMON-ELSEVIER SCIENCE LTD. - 0016-7037 .- 1872-9533. ; 255, s. 163-187
  • Tidskriftsartikel (refereegranskat)abstract
    • This study explores the suitability of apatite as a tracer of the source(s), chemistry, and evolution of ore-forming hydrothermal fluids. This is tested by analysing the halogen (F, Cl, Br, and I), stable Cl isotopic, and trace element compositions of fluorapatite from the regional-scale Olserum-Djupedal rare earth element (REE) phosphate mineralisation in SE Sweden, which is dominated by monazite-(Ce), xenotime-(Y), and fluorapatite. The primary hydrothermal fluid flow system is recorded in a sequence from proximal granite-hosted to distal metasediment-hosted fluorapatite. Along this sequence, primary fluorapatite shows a gradual increase of Cl and Br concentrations and in (Gd/Yb)(N), a decrease of F and I concentrations, a decrease in delta Cl-37 values, in (La/Sm)(N), and partly in (La/Yb)(N) and (Y/Ho)(N). Local compositional differences of halogen and trace element concentrations have developed along rims and in domains adjacent to fractures of fluorapatite due to late-stage partial reaction with fracture fluids. These differences are insignificant compared to the larger deposit-scale zoning. This suggests that apatite can retain the primary record of the original ore-forming fluid despite later overprinting fluid events. The agreement between Br/Cl and I/Cl ratios of apatite and those of co-existing fluid inclusions at lower temperatures indicates that only a minor fractionation of Br from I occurs during apatite precipitation. The halogen ratios of apatite can thus be used as a first-order estimate for the composition of the ore-forming fluid. Taking the small fractionation factors for Cl isotopes between apatite and co-existing fluid at high temperatures into account, we propose that the Cl isotopic composition of apatite and the halogen ratios derived from the apatite composition can be used jointly to trace the source(s) of ore-forming fluids. By contrast, most trace elements incorporated in apatite are affected by the host rock environment and by fluid-mineral partitioning due to growth competition between co-crystallising minerals. Collectively, apatite is sensitive to changing fluid compositions, yet it is also able to record the character of primary ore-forming fluids. Thus, apatite is suitable for tracing the origin, chemistry, and evolution of fluids in hydrothermal ore-forming settings.
  • Barnes, Christopher, et al. (författare)
  • High-spatial resolution dating of monazite and zircon reveals the timing of subduction–exhumation of the Vaimok Lens in the SeveNappe Complex (Scandinavian Caledonides)
  • 2019
  • Ingår i: Contributions to Mineralogy and Petrology. - Springer Berlin/Heidelberg. - 0010-7999. ; 174:1
  • Tidskriftsartikel (refereegranskat)abstract
    • In-situ monazite Th–U–total Pb dating and zircon LA–ICP–MS depth-profiling was applied to metasedimentary rocks from the Vaimok Lens in the Seve Nappe Complex (SNC), Scandinavian Caledonides. Results of monazite Th–U–total Pb dating, coupled with major and trace element mapping of monazite, revealed 603 ± 16 Ma Neoproterozoic cores surrounded byrims that formed at 498 ± 10 Ma. Monazite rim formation was facilitated via dissolution–reprecipitation of Neoproterozoic monazite. The monazite rims record garnet growth as they are depleted in Y2O3 with respect to the Neoproterozoic cores. Rims are also characterized by relatively high SrO with respect to the cores. Results of the zircon depth-profiling revealed igneous zircon cores with crystallization ages typical for SNC metasediments. Multiple zircon grains also exhibit rims formedby dissolution–reprecipitation that are defined by enrichment of light rare earth elements, U, Th, P, ± Y, and ± Sr. Rims also have subdued Eu anomalies (Eu/Eu* ≈ 0.6–1.2) with respect to the cores. The age of zircon rim formation was calculated from three metasedimentary rocks: 480 ± 22 Ma; 475 ± 26 Ma; and 479 ± 38 Ma. These results show that both monazite and zircon experienced dissolution–reprecipitation under high-pressure conditions. Caledonian monazite formed coeval with garnet growth during subduction of the Vaimok Lens, whereas zircon rim formation coincided with monazite breakdown to apatite, allanite and clinozoisite during initial exhumation.
  • Blicharska, Malgorzata, et al. (författare)
  • Effects of management intensity, function and vegetation on the biodiversity in urban ponds
  • 2016
  • Ingår i: Urban Forestry & Urban Greening. - 1618-8667 .- 1610-8167. ; 20, s. 103-112
  • Tidskriftsartikel (refereegranskat)abstract
    • Ponds are important elements of green areas in cities that help counteract the negative consequences of urbanization, by providing important habitats for biodiversity in cities and being essential nodes in the overall landscape-scale habitat network. However, there is relatively little knowledge about the impacts of pond management intensity, function and environmental variables on urban pond biodiversity. In this study we addressed this gap by investigating which factors were correlated with the level of biodiversity in urban ponds, indicated by species richness of aquatic insects, in Stockholm, Sweden. Our study did not confirm any direct link between the perceived intensity of management or function of ponds and overall biodiversity. However, it seems that management can influence particular groups of species indirectly, since we found that Trichoptera richness (Caddisflies) was highest at intermediate management intensity. We suggest that this is caused by management of vegetation, as the amount of floating and emergent vegetation was significantly correlated with both the overall species richness and the richness of Trichoptera (Caddisflies). This relationship was non-linear, since ponds with an intermediate coverage of vegetation had the highest richness. Interestingly, the amount of vegetation in the pond was significantly affected by pond function and pond management. The overall species richness and richness of Trichoptera were also positively correlated with pond size. Since we found that the pattern of relations between species richness and environmental variables differed between the insect groups we suggest that it will be difficult to provide overall design and management recommendations for ponds in urban green areas. Therefore, it is recommended that to provide high aquatic diversity of species in urban areas one should aim at promoting high diversity of different types of ponds with differing management and environmental factors that shape them.
  • Blicharska, Malgorzata, et al. (författare)
  • Is there a relationship between socio-economic factors and biodiversity in urban ponds? A study in the city of Stockholm
  • 2017
  • Ingår i: Urban Ecosystems. - 1083-8155 .- 1573-1642. ; 20:6, s. 1209-1220
  • Tidskriftsartikel (refereegranskat)abstract
    • Urban small water bodies, such as ponds, are essential elements of human socio-economic landscapes. Ponds also provide important habitats for species that would otherwise not survive in the urban environment. Knowledge on the biodiversity of urban ponds and the relationship between their ecological value and factors linked to urbanization and socio-economic status is crucial for decisions on where and how to establish and manage ponds in cities to deliver maximum biodiversity benefits. Our study investigates if the pattern of urban-pond biodiversity can be related to different socio-economic factors, such as level of wealth, education or percentage of buildings of different types. Because of lack of previous studies investigating that, our study is of exploratory character and many different variables are used. We found that the biodiversity of aquatic insects was significantly negatively associated with urbanisation variables such as amount of buildings and number of residents living around ponds. This relationship did not differ depending on the spatial scale of our investigation. In contrast, we did not find a significant relationship with variables representing socio-economic status, such as education level and wealth of people. This latter result suggests that the socio-economic status of residents does not lead to any particular effect in terms of the management and function of ponds that would affect biodiversity. However, there is a need for a finer-scale investigation of the different potential mechanism in which residents in areas with differing socio-economic status could indirectly influence ponds.
  • Budd, David A., et al. (författare)
  • Magma reservoir dynamics at Toba caldera, Indonesia, recorded by oxygen isotope zoning in quartz
  • 2017
  • Ingår i: Scientific Reports. - 2045-2322 .- 2045-2322. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • Quartz is a common phase in high-silica igneous rocks and is resistant to post-eruptive alteration, thus offering a reliable record of magmatic processes in silicic magma systems. Here we employ the 75 ka Toba super-eruption as a case study to show that quartz can resolve late-stage temporal changes in magmatic δ18O values. Overall, Toba quartz crystals exhibit comparatively high δ18O values, up to 10.2‰, due to magma residence within, and assimilation of, local granite basement. However, some 40% of the analysed quartz crystals display a decrease in δ18O values in outermost growth zones compared to their cores, with values as low as 6.7‰ (maximum ∆core−rim = 1.8‰). These lower values are consistent with the limited zircon record available for Toba, and the crystallisation history of Toba quartz traces an influx of a low-δ18O component into the magma reservoir just prior to eruption. Here we argue that this late-stage low-δ18O component is derived from hydrothermally-altered roof material. Our study demonstrates that quartz isotope stratigraphy can resolve magmatic events that may remain undetected by whole-rock or zircon isotope studies, and that assimilation of altered roof material may represent a viable eruption trigger in large Toba-style magmatic systems.
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