| 1. |
- Altewischer, Andrea, et al.
(author)
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Habitat preferences of male Corn Buntings Emberiza calandra in north-eastern Germany
- 2015
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In: Acta Ornithologica. - 0001-6454 .- 1734-8471. ; 50:1, s. 1-10
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Journal article (peer-reviewed)abstract
- Agricultural ecosystems have faced dramatic changes during past decades, resulting in a dramatic loss of farmland biodiversity. The Corn Bunting Emberiza calandra is considered a suitable indicator for the conservation value of farmland habitats, and has recently suffered strong declines throughout much of its European range. As a basis for targeted conservation measures, we investigated the habitat preferences of this species in north-eastern Germany by comparing the composition of male territories with randomly chosen control sites. A territory was defined as the area within a radius of 150 meters around the assumed centre of the territory, as the majority of nests is found within this radius. To assess food availability for nestlings, arthropod abundance within the most abundant land use types i.e. crop fields, fallows, grassland as well as within unploughed strips was investigated. In total we found 102 male Corn Bunting territories, which were mainly composed of crop fields (50%), grassland (28%), and fallows (12%). Territories compared with control sites were characterized by a lower proportion of crop fields, a higher proportion of fallows, more diverse land use types, more abundant field boundaries, unploughed strips, and tracks, and a higher availability of song posts. However, neither the number of larger (≥ 1 cm), smaller (< 1 cm) or all arthropods differed significantly among analysed land use types i.e. crop fields, fallows, grassland, unploughed strips. Our study confirms the significance of habitat heterogeneity and especially of sites with sparse vegetation (fallows > 10%) and song posts (> 70 m ‘linear song posts’ or > 1 solitary post per ha) for the habitat selection of male Corn Buntings. We conclude that measures to halt population declines of Corn Buntings seem to be relatively easy to implement, provided that farmers are granted a fair compensation.
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| 2. |
- Axelsson, Emelie, et al.
(author)
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Rutile R632-A New Natural Reference Material for U-Pb and Zr Determination
- 2018
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In: Geostandards and Geoanalytical Research. - : Wiley. - 1639-4488 .- 1751-908X. ; 42:3, s. 319-338
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Journal article (peer-reviewed)abstract
- A new natural rutile reference material is presented, suitable for U-Pb dating and Zr-in-rutile thermometry by microbeam methods. U-Pb dating of rutile R632 using laser ablation ICP-MS with both magnetic sector field and quadrupole instruments as well as isotope dilution-thermal ionisation mass spectrometry yielded a concordia age of 496 +/- 2Ma. The high U content (>300gg(-1)) enabled measurement of high-precision U-Pb ages despite its young age. The sample was found to have a Zr content of 4294 +/- 196gg(-1), which makes it an excellent complementary reference material for Zr-in-rutile thermometry. Individual rutile grains have homogeneous compositions of a number of other trace elements including V, Cr, Fe, Nb, Mo, Sn, Sb, Hf, Ta and W. This newly characterised material significantly expands the range of available rutile reference materials relevant for age and temperature determinations.
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