@misc{PavesiTiedemannDeMatthaeisetal.2013, author = {Pavesi, Laura and Tiedemann, Ralph and De Matthaeis, Elvira and Ketmaier, Valerio}, title = {Genetic connectivity between land and sea}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-401110}, pages = {19}, year = {2013}, abstract = {Introduction: We examined patterns of genetic divergence in 26 Mediterranean populations of the semi-terrestrial beachflea Orchestia montagui using mitochondrial (cytochrome oxidase subunit I), microsatellite (eight loci) and allozymic data. The species typically forms large populations within heaps of dead seagrass leaves stranded on beaches at the waterfront. We adopted a hierarchical geographic sampling to unravel population structure in a species living at the sea-land transition and, hence, likely subjected to dramatically contrasting forces. Results: Mitochondrial DNA showed historical phylogeographic breaks among Adriatic, Ionian and the remaining basins (Tyrrhenian, Western and Eastern Mediterranean Sea) likely caused by the geological and climatic changes of the Pleistocene. Microsatellites (and to a lesser extent allozymes) detected a further subdivision between and within the Western Mediterranean and the Tyrrhenian Sea due to present-day processes. A pattern of isolation by distance was not detected in any of the analyzed data set. Conclusions: We conclude that the population structure of O. montagui is the result of the interplay of two contrasting forces that act on the species population genetic structure. On one hand, the species semi-terrestrial life style would tend to determine the onset of local differences. On the other hand, these differences are partially counter-balanced by passive movements of migrants via rafting on heaps of dead seagrass leaves across sites by sea surface currents. Approximate Bayesian Computations support dispersal at sea as prevalent over terrestrial regionalism.}, language = {en} } @article{PavesiDeidunDeMatthaeisetal.2012, author = {Pavesi, Laura and Deidun, Alan and De Matthaeis, Elvira and Tiedemann, Ralph and Ketmaier, Valerio}, title = {Mitochondrial DNA and microsatellites reveal significant divergence in the beachflea Orchestia montagui (Talitridae: Amphipoda)}, series = {Aquatic sciences : research across boundaries}, volume = {74}, journal = {Aquatic sciences : research across boundaries}, number = {3}, publisher = {Springer}, address = {Basel}, issn = {1015-1621}, doi = {10.1007/s00027-012-0250-y}, pages = {587 -- 596}, year = {2012}, abstract = {Talitrids are semiterrestrial crustacean amphipods inhabiting sandy and rocky beaches; they generally show limited active dispersal over long distances. In this study we assessed levels of population genetic structure and variability in the talitrid amphipod Orchestia montagui, a species strictly associated to stranded decaying heaps of the seagrass Posidonia oceanica. The study is based on six populations (153 individuals) and covers five basins of the Mediterranean Sea (Tyrrhenian, Ionian, Adriatic, Western and Eastern basins). Samples were screened for polymorphisms at a fragment of the mitochondrial DNA (mtDNA) coding for the cytochrome oxidase subunit I gene (COI; 571 base pairs) and at eight microsatellite loci. MtDNA revealed a relatively homogeneous haplogroup, which clustered together the populations from the Western, Tyrrhenian and Eastern basins, but not the populations from the Adriatic and Ionian ones; microsatellites detected two clusters, one including the Adriatic and Ionian populations, the second grouping all the others. We found a weak geographic pattern in the genetic structuring of the species, with a lack of isolation by distance at either class of markers. Results are discussed in terms of probability of passive dispersal over long distances through heaps of seagrass.}, language = {en} } @article{PavesiTiedemannDeMatthaeisetal.2013, author = {Pavesi, Laura and Tiedemann, Ralph and De Matthaeis, Elvira and Ketmaier, Valerio}, title = {Genetic connectivity between land and sea - the case of the beachflea Orchestia montagui (Crustacea, Amphipoda, Talitridae) in the Mediterranean Sea}, series = {Frontiers in zoology}, volume = {10}, journal = {Frontiers in zoology}, number = {4-5}, publisher = {BioMed Central}, address = {London}, issn = {1742-9994}, doi = {10.1186/1742-9994-10-21}, pages = {19}, year = {2013}, abstract = {Introduction: We examined patterns of genetic divergence in 26 Mediterranean populations of the semi-terrestrial beachflea Orchestia montagui using mitochondrial (cytochrome oxidase subunit I), microsatellite (eight loci) and allozymic data. The species typically forms large populations within heaps of dead seagrass leaves stranded on beaches at the waterfront. We adopted a hierarchical geographic sampling to unravel population structure in a species living at the sea-land transition and, hence, likely subjected to dramatically contrasting forces. Results: Mitochondrial DNA showed historical phylogeographic breaks among Adriatic, Ionian and the remaining basins (Tyrrhenian, Western and Eastern Mediterranean Sea) likely caused by the geological and climatic changes of the Pleistocene. Microsatellites (and to a lesser extent allozymes) detected a further subdivision between and within the Western Mediterranean and the Tyrrhenian Sea due to present-day processes. A pattern of isolation by distance was not detected in any of the analyzed data set. Conclusions: We conclude that the population structure of O. montagui is the result of the interplay of two contrasting forces that act on the species population genetic structure. On one hand, the species semi-terrestrial life style would tend to determine the onset of local differences. On the other hand, these differences are partially counter-balanced by passive movements of migrants via rafting on heaps of dead seagrass leaves across sites by sea surface currents. Approximate Bayesian Computations support dispersal at sea as prevalent over terrestrial regionalism.}, language = {en} }