| 1. |
- Lopes-Lima, M., et al.
(author)
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Integrative phylogenetic, phylogeographic and morphological characterisation of the Unio crassus species complex reveals cryptic diversity with important conservation implications
- 2024
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In: Molecular Phylogenetics and Evolution. - : Academic Press Inc.. - 1055-7903 .- 1095-9513. ; 195
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Journal article (peer-reviewed)abstract
- The global decline of freshwater mussels and their crucial ecological services highlight the need to understand their phylogeny, phylogeography and patterns of genetic diversity to guide conservation efforts. Such knowledge is urgently needed for Unio crassus, a highly imperilled species originally widespread throughout Europe and southwest Asia. Recent studies have resurrected several species from synonymy based on mitochondrial data, revealing U. crassus to be a complex of cryptic species. To address long-standing taxonomic uncertainties hindering effective conservation, we integrate morphometric, phylogenetic, and phylogeographic analyses to examine species diversity within the U. crassus complex across its entire range. Phylogenetic analyses were performed using cytochrome c oxidase subunit I (815 specimens from 182 populations) and, for selected specimens, whole mitogenome sequences and Anchored Hybrid Enrichment (AHE) data on ∼ 600 nuclear loci. Mito-nuclear discordance was detected, consistent with mitochondrial DNA gene flow between some species during the Pliocene and Pleistocene. Fossil-calibrated phylogenies based on AHE data support a Mediterranean origin for the U. crassus complex in the Early Miocene. The results of our integrative approach support 12 species in the group: the previously recognised Unio bruguierianus, Unio carneus, Unio crassus, Unio damascensis, Unio ionicus, Unio sesirmensis, and Unio tumidiformis, and the reinstatement of five nominal taxa: Unio desectus stat. rev., Unio gontierii stat. rev., Unio mardinensis stat. rev., Unio nanus stat. rev., and Unio vicarius stat. rev. Morphometric analyses of shell contours reveal important morphospace overlaps among these species, highlighting cryptic, but geographically structured, diversity. The distribution, taxonomy, phylogeography, and conservation of each species are succinctly described.
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| 2. |
- Horky, P., et al.
(author)
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Parasite-induced alterations of host behaviour in a riverine fish: the effects of glochidia on host dispersal
- 2014
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In: Freshwater Biology. - : Wiley. - 0046-5070. ; 59:7, s. 1452-1461
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Journal article (peer-reviewed)abstract
- Parasitic species can affect host behaviour in various ways. Freshwater mussels of the superfamily Unionoidea have a glochidia larva that is parasitic on fish. Our aim was to evaluate whether fish exposed to glochidia have distinct behaviour that could affect the upstream dispersal of the parasite. Many freshwater mussels are highly endangered, and understanding the relationships with their hosts is important for their conservation. However, research on the behavioural effects of parasitism on fish host activity and/or the upstream dispersal of mussel larvae in nature has received little attention. Specifically, we examined a fish (the chub, Squalius cephalus) that hosts the larval stage of a freshwater bivalve (Anodonta anatina) and investigated alterations in host behaviour induced by the parasite. One laboratory and two field experiments were conducted using passive integrated transponder systems and radio-telemetry. Infected fish were generally less active in the laboratory and, in the field, dispersed less far upstream. Moreover, radio-telemetry revealed a habitat shift by the infected fish, which were found further from the riverbank. We suggest that behavioural changes in the fish that are induced by glochidia do not facilitate the long-distance dispersal of the mussel but rather cause reductions in fish activity and slight habitat shifts. Possible consequences of such behavioural alterations are discussed.
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| 3. |
- Sousa, Ronaldo, et al.
(author)
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The role of anthropogenic habitats in freshwater mussel conservation
- 2021
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In: Global Change Biology. - : John Wiley & Sons. - 1354-1013 .- 1365-2486. ; 27, s. 2298-2314
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Journal article (peer-reviewed)abstract
- Anthropogenic freshwater habitats may provide undervalued prospects for long-term conservation as part of species conservation planning. This fundamental, but overlooked, issue requires attention considering the pace that humans have been altering natural freshwater ecosystems and the accelerated levels of biodiversity decline in recent decades. We compiled 709 records of freshwater mussels (Bivalvia, Unionida) inhabiting a broad variety of anthropogenic habitat types (from small ponds to large reservoirs and canals) and reviewed their importance as refuges for this faunal group. Most records came from Europe and North America, with a clear dominance of canals and reservoirs. The dataset covered 228 species, including 34 threatened species on the IUCN Red List. We discuss the conservation importance and provide guidance on how these anthropogenic habitats could be managed to provide optimal conservation value to freshwater mussels. This review also shows that some of these habitats may function as ecological traps owing to conflicting management practices or because they act as a sink for some populations. Therefore, anthropogenic habitats should not be seen as a panacea to resolve conservation problems. More information is necessary to better understand the trade-offs between human use and the conservation of freshwater mussels (and other biota) within anthropogenic habitats, given the low number of quantitative studies and the strong biogeographic knowledge bias that persists.
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