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- Rosin, Zuzanna
(författare)
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Cepaea nemoralis (Gastropoda: Pulmonata) in Poland: patterns of variation in a range-expanding species
- 2019
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Ingår i: Biological Journal of the Linnean Society. - 0024-4066 .- 1095-8312. ; 127, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- A countrywide data set of 1048 samples of the European land snail Cepaea nemoralis (L.) from Poland was assembled from both published and unpublished sources. Analyses of shell colour and banding polymorphism revealed distinctive patterns of variation. While the frequency of brown shells showed a clear geographical pattern related to climate, other morphs showed no such clear trends. Variation among populations was great, but little of this could be accounted for by variation among regions. Spatial autocorrelation was generally restricted to very short distances, of the order of 20 km or less. Variation with habitat was found in the form of an excess of brown shells in shaded habitats and an excess of yellow and yellow effectively unbanded shells in open habitats, although this was not universal. The data suggest that cases of long-distance, passive dispersal followed by more local spread account for much of the variation, and that strong selection related to habitat may be obscured by different sources of populations within a few kilometres of each other. The data are now available to track changes over time.
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| 2. |
- Rosin, Zuzanna
(författare)
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Thrush anvils are calcium source hotspots for many bird species
- 2019
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 128, s. 603-610
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Tidskriftsartikel (refereegranskat)abstract
- Calcium is one of the most important elements determining reproductive success in birds, and snail shells are a well-known source of calcium for egg-laying females. In Europe, song thrushes, Turdus philomelos, break snails open at locations called anvils, eat the soft parts and leave the broken shells. Based on observational studies in 2011-2017 in western Poland, we showed that thrush anvils were visited by 54 other bird species (mainly smaller species) that collected the broken shell fragments. The frequency of visits to anvils differed among species and changed over the course of the breeding season, but anvils were especially used by females during the pre-laying period. Our study is the first description of such widespread exploitation of thrush anvils by other bird species, and we think that this phenomenon has been overlooked owing to the difficulties in recording anvils located, for example, on single small stones, stumps of felled trees and man-made objects such as glass bottles. We conclude that thrush anvils can be an important source of calcium for many bird species that adapt behaviourally to use these places. Hence, anvils should be recognized as localized hotspots for bird diversity.
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