Search

Abstract The Italian‐native Mediterranean brown trout (Salmo ghigii) is a seriously threatened freshwater fish, especially by anthropogenic hybridisation with the domestic strains of Atlantic origin that have been repeatedly released into the wild for angling. A PCR‐restriction fragment length polymorphism (RFLP) assay of the diagnostic lactate dehydrogenase chain‐1 (LDH‐C1) gene sequences has been routinely applied to distinguish exotic from native brown trout lineages and detect Atlantic introgression signals in the Mediterranean wild populations. Here, we used dermal swab DNA obtained from 28 wild trout to improve laboratory procedures to genetically characterise trout samples at the LDH‐C1gene through (1) a capillary electrophoresis analysis of the RFLP fragments and (2) the optimisation of a diagnostic single nucleotide polymorphism analysable through mini‐sequencing approaches. The developed methods were fully consistent with those obtained through the traditional approach, but their analytical process is almost entirely automated and digitalised, thus improving result readability and accuracy in the detection of alien introgressed traces in wild Mediterranean brown trout populations.

This corrects the article published on Journal of Limnology 2022;81(s2):2136 (https://doi.org/10.4081/jlimnol.2022.2136 ). The Genbank accession numbers in the footnote of Table 1 are incorrect. The correct Table 1 footnote is: “PAN, Panperduto Dam; SL, Somma Lombardo; PV, Pavia; OG, Oglio River; *unique haplotypes, GenBank Acc. No. OQ676377-OQ676381.”

Freshwater ecosystems are heavily altered by human activities, with anthropic introductions of non-native species substantially contributing to their biotic degradation. The invasion by alien species can alter ecosystem balances with direct and indirect impacts across different levels of biotic organization. The number of invasive alien species is particularly high in Mediterranean fresh waters including rivers draining in the northern Adriatic basins. Here, the Padanian barbel Barbus plebejus endemic to the Padano-Venetian district, is threatened by the introduction of the European barbel Barbus barbus via competition and introgressive hybridization. In this study, we genetically characterised using the partial mitochondrial DNA Cytochrome b gene, barbels present in two main tributaries of the Po River, the lower Ticino and Oglio rivers where the two species are suspected to co-occur. Since the two river sections are highly regulated and present severe hydrological alterations caused by dams and other hydraulic structures, the aim of the study was to provide information on the barbel populations composition in these systems to foster the implementation of more suitable management plans aimed at the conservation of the native species. A total of 86 barbel have been analysed (50 in the Ticino River and 36 in the Oglio River) corresponding to 13 haplotypes of which 8 were phylogenetically attributed to B. barbus and five to B. plebejus. The high haplotypic diversity and the unimodal trend evidenced by the mismatch distribution analysis for B. barbus haplotypes support a potential demographic expansion. Altogether, these results highlighted that B. barbus is progressively expanding in northern Italy while posing a serious risk for the conservation of the native B. plebejus, stressing the need to actively focus ecosystem and fisheries management regulations to stop B. barbus from spreading further throughout northern Italy.

Abstract The dispersal routes of taxa with transoceanic disjunctions remain poorly understood, with the potential roles of Antarctica not yet demonstrated. Mosses are suitable organisms to test direct intra‐Antarctic dispersal, as major component of the extant Antarctic flora, with the cosmopolitan moss Bryum argenteum as ideal target species. We analyzed the genetic structure of B. argenteum to provide an evolutionary time frame for its radiation and shed light into its historical biogeography in the Antarctic region. We tested two alternative scenarios: (a) intra‐Antarctic panmixia and (b) intra‐Antarctic genetic differentiation. Furthermore, we tested for evidence of the existence of specific intra‐Antarctic dispersal routes. Sixty‐seven new samples (40 collected in Antarctica) were sequenced for ITS nrDNA and rps4 cpDNA regions, and phylogenetic trees of B. argenteum were constructed, with a focus on its Southern Hemisphere. Combining our new nrDNA dataset with previously published datasets, we estimated time‐calibrated phylogenies based on two different substitution rates (derived from angiosperms and bryophytes) along with ancestral area estimations. Minimum spanning network and pairwise genetic distances were also calculated. B. argenteum was potentially distributed across Africa and Antarctica soon after its origin. Its earliest intra‐Antarctic dispersal and diversification occurred during a warming period in the Pliocene. On the same timescale, a radiation took place involving a dispersal event from Antarctica to the sub‐Antarctic islands. A more recent event of dispersal and diversification within Antarctica occurred during a warm period in the Pleistocene, creating favorable conditions also for its colonization outside the Antarctic continent worldwide. We provide evidence supporting the hypothesis that contemporary populations of B. argenteum in Antarctica integrate a history of both multiple long‐range dispersal events and local persistence combined with in situ diversification. Our data support the hypothesis that B. argenteum has been characterized by strong connectivity within Antarctica, suggesting the existence of intra‐Antarctic dispersal routes.

The Turkey oak (Quercus cerris L.) is widely distributed in Italy, where it is the ecologically dominant oak on sandy and acidic soil. In this work, we analysed 23 natural populations by means of eight SSR (microsatellite) markers, to obtain the first synthetic map of genetic variability for this species and to study its dispersion during the Holocene, due to the possibility that at least one refugium during the Last Glacial Maximum was in Italy. The analyses showed a good amount of genetic variability together with fair differentiation between populations, as indicated by FST = 0.059. A Bayesian analysis of the amount of admixture among populations revealed the presence of four putative gene pools of origin and a rough subdivision of the populations according to their geographic location, as confirmed by the spatial analysis. No evidence for the existence of putative refugial populations was found; however, this study paves the way for the planning of conservation strategies also with regard to the relationship between Turkey oak and other oak species in Italy.

Abstract The Italian peninsula is a biodiversity hotspot, with its freshwater fish fauna characterized by high levels of local endemism. Two endemic fluvio‐lacustrine fishes of the genus Barbus (barbel, family Cyprinidae) have allopatric distributions in the Tyrrhenian and Adriatic basins of Italy. Barbus plebejus inhabits the mid‐ to northern Adriatic basins, while B. tyberinus is widespread in all central‐northern basins draining into the Tyrrhenian Sea. For basins in Southern Italy draining into the southern parts of these seas, there remains a knowledge gap on their barbel populations due to no previous genetic and morphological studies, despite their apparent biogeographic isolation. Correspondingly, this study quantified the presence and distribution of barbels in the Adriatic and Tyrrhenian basins of Southern Italy through genetic and morphological analyses of 197 fish sampled across eight populations. Testing of how local isolation has influenced the evolution and persistence of these populations was completed by examining sequence variation at two mitochondrial loci (cytochrome b and D‐loop) and performing geometric morphometric analyses of body shape, plus measuring 11 morphometric and meristic characters. Phylogenetic and morphological analyses revealed the presence of two genetically distinct lineages that differed significantly from adjacent B. tyberinus and B. plebejus populations. These two new taxa, here described as SI1 and SI2 Barbus lineages, are highly structured and reflect a complex mosaic biogeographic pattern that is strongly associated with the underlying hydrographical scenarios of the basins. The geographic isolation of these basins thus has high evolutionary importance that has to be considered for maintaining endemism.