| 1. |
- Engler, Jan O., et al.
(författare)
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Range expansion and retraction along a moving contact zone has no effect on the genetic diversity of two passerine birds
- 2016
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Ingår i: Ecography. - : Wiley. - 0906-7590. ; 39:9, s. 884-893
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Tidskriftsartikel (refereegranskat)abstract
- Disentangling the factors shaping species distributions remains a central goal in biogeography, ecology and evolutionary biology. The extrinsic pressures that may facilitate range shifts, such as climatic factors or biotic interactions are well known. However, in contrast, the possible intrinsic factors are manifold and hard to generalize across taxa. Recently, several theoretical studies have investigated the consequences of moving range borders on genetic diversity. However, empirical studies that support or refute these theoretical predictions are scarce. Moving contact zones between parapatric sister species are suitable models to test these hypotheses. Changes in genetic diversity can be tested simultaneously along the expanding and receding edges of two species of the contact zone while accounting for intra-specific effects (e.g. introgression). The two Old World warblers Hippolais polyglotta and H. icterina form a narrow moving contact zone, where interspecific interactions are suspected to be the main factor shaping this zone. We investigated the population genetic structure of both species along a transect ranging from the core range of the expanding H. polyglotta across the contact zone and far into the range of the receding H. icterina. The theoretical predictions of changes in genetic diversity at the range edges were tested. No gradual change in genetic diversity was detected for both the expanding and the receding range margin. Furthermore, no genetic structure was found in either species supporting the hypothesis that long distance dispersal (LDD) occurs frequently due to the high mobility of these long-distance migrants. The results suggest that when dispersal propensity is high and accompanied by frequent LDD events, then neither an enrichment nor a depletion of alleles along moving range edges would be detected. This these species as the probability to retain genetic diversity during exogenous induced range shifts is high in such mobile species.
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| 2. |
- Lafage, Denis, et al.
(författare)
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Short-term resilience of arthropod assemblages after spring flood, with focus on spiders (Arachnida Araneae) and carabids (Coleoptera: Carabidae)
- 2015
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Ingår i: Ecohydrology. - : John Wiley & Sons. - 1936-0584 .- 1936-0592. ; 8:8, s. 1584-1599
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Tidskriftsartikel (refereegranskat)abstract
- Despite the expected increase in extreme flood frequency, the manner in which terrestrial arthropods cope with regular submersion of their habitat remains poorly understood in meadows, especially in temperate floodplains. Here, we studied the recolonization dynamics of arthropods after a severe spring flood in the Loire Valley (France). We carried out analyses at the community (order or family identification level) and species scales, focusing on the assemblages of two dominant and diverse groups: carabids and spiders. Our objectives were the following: (i) to describe the temporal changes in community structure after flooding and (ii) to assess the influence of landscape configuration on recolonization patterns of species and their functional traits. Fieldwork was performed along three sampling transects, by using 75 pitfall traps, in 2012. A total of 14767 arthropods belonging to 87 families were trapped, including 5538 spiders (55 species) and 3396 carabids (66 species). Multivariate analyses discriminated assemblages from flooded and non-flooded habitats and revealed changes over time in arthropod families and species after flood withdrawal. In particular, wolf spiders (Lycosidae) were the first to recolonize, whereas other groups clearly avoided flooded sites. Our results also revealed that short distances to hedgerows, and to a lesser extent, distance to woodlands, favoured the recolonization of large and ground-running spiders. In conclusion, our study shows the short-term resilience of certain groups or stenotopic species to flooding and also the relevance of multi-taxon-based studies. The presence of hedgerows has to be considered carefully in management plans because of their role of refuge during flooding. Copyright (c) 2015 John Wiley & Sons, Ltd.
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| 3. |
- Mege, Pascal, et al.
(författare)
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Partial Opsin Sequences Suggest UV-Sensitive Vision is Widespread in Caudata
- 2016
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Ingår i: Evolutionary biology. - : Springer Science and Business Media LLC. - 0071-3260 .- 1934-2845. ; 43:1, s. 109-118
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Forskningsöversikt (refereegranskat)abstract
- Ultraviolet (UV) vision exists in several animal groups. Intuitively, one would expect this trait to be favoured in species living in bright environments, where UV light is the most present. However, UV sensitivity, as deduced from sequences of UV photoreceptors and/or ocular media transmittance, is also present in nocturnal species, raising questions about the selective pressure maintaining this perceptual ability. Amphibians are among the most nocturnal vertebrates but their visual ecology remains poorly understood relative to other groups. Perhaps because many of these species breed in environments that filter out a large part of UV radiation, physiological and behavioural studies of UV sensitivity in this group are scarce. We investigated the extent of UV vision in Caudata, the order of amphibians with the most nocturnal habits. We could recover sequences of the UV sensitive SWS1 opsin in 40 out of 58 species, belonging to 6 families. In all of these species, the evidence suggests the presence of functional SWS1 opsins under purifying selection, potentially allowing UV vision. Interestingly, most species whose opsin genes failed to amplify exhibited particular ecological features that could drive the loss of UV vision. This likely wide distribution of functional UV photoreceptors in Caudata sheds a new light on the visual ecology of amphibians and questions the function of UV vision in nocturnal animal species.
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