Phylogeography and colonization history of Lesser Black-backed Gulls (Larus fuscus) as revealed by mtDNA sequences

Because of the differential amplitude of climatic oscillations, species living at northern latitudes are subject to more frequent and more severe range oscillations than species at southern latitudes. As a consequence, northern populations should, on average, be phylogenetically younger and possess less phylogeographical structure than closely related taxa further south. To test these predictions, we studied the mitochondrial-genetic population structure of NW Palearctic Lesser Black-backed Gulls (Larus fuscus group [ = LBBG], five taxa) breeding at temperate to boreal latitudes from Iceland to the Taimyr Peninsula. Results were compared with those previously obtained (Liebers et al. 2001. Mol. Ecol. 10: 2447) for more southerly breeding Yellow-legged Gulls (Larus cachinnans group, six taxa from the Atlantic Islands to Mongolia). Sequences of the hypervariable region I (HVR-I) of the mitochondrial control region revealed low within- and between-taxon sequence divergence, little genetic variation, a shallow haplotype phylogeny and poor phylogeographical structure in LBBGs compared with Yellow-legged Gulls. Haplotype frequencies among the five northern taxa formed a stepped cline with significant gene flow restriction between the forms heuglini and fuscus, probably indicating a secondary contact with (partial?) reproductive isolation. Western forms of LBBG, among which mitochondrial gene flow appears unrestricted, show genetic signs of postglacial range expansion and population growth. The Larus fuscus group is derived from a cachinnans- like ancestral population, probably in the Aralo-Caspian basin, and spread from east (NW Siberia) to west within the Palearctic

The herring gull complex is not a ring species.

Under what circumstances speciation in sexually reproducing animals can occur without geographical disjunction is still controversial. According to the ring-species model, a reproductive barrier may arise through 'isolation by distance' when peripheral populations of a species meet after expanding around some uninhabitable barrier. The classical example of this kind of speciation is the herring gull (Larus argentatus) complex, with a circumpolar distribution in the Northern Hemisphere. Based on mitochondrial DNA variation among 21 gull taxa, we show that members of this complex differentiated largely in allopatry following multiple vicariance and long-distance-colonization events, not primarily through isolation by distance. Reproductive isolation evolved more rapidly between some lineages than between others, irrespective of their genetic distance. Extant taxa are the result of divergent as well as reticulate evolution between two ancestral lineages originally separated in a North Atlantic refugium and a continental Eurasian refugium, respectively. Continental birds expanded along the entire north Eurasian coast and via Beringia into North America. Contrary to the ring-species model, we find no genetic evidence for a closure of the circumpolar ring through colonization of Europe by North American herring gulls. However, closure of the ring in the opposite direction may be imminent, with lesser black-backed gulls about to colonize North America

Phylogeography of the southern skua complex - rapid colonisation of the southern hemisphere during a glacial period and reticulate evolution

Whilst we have now a good understanding how past glaciation influenced species at the northern hemisphere, our knowledge of patterns and modes of speciation is far more limited for the southern hemisphere. We provide mtDNA based data on the phylogeography of a circumpolar distributed southern hemisphere seabird group—the southern skua complex (Catharacta spp.). Diversification of southern skuas dates between 210,000 yBP and 150,000 yBP and coincides with a glacial spanning 230,000–140,000 yBP. Skuas most likely first inhabited the Antarctic continent, in the course of global cooling and increasing glaciation spread to the sub-antarctic islands and Tristan da Cunha and finally colonized Patagonia and the Falkland Islands at the glacial maximum. Despite significant differences between taxa most populations still exchange genes with neighboring populations of other taxa and speciation is incomplete

Forschungsdatenmanagementkonzept für die deutsche Meeresforschung

Die deutsche Meeresforschung benötigt ein kollaboratives "Datenökosystem": Eine gemeinsam nutzbare, verteilte, leistungsstarke und stetig betriebene Forschungsdateninfrastruktur, um Information und Wissen zu sichern und Forschungsdaten für Nutzer*innen aus Wissenschaft, Behörden, Wirtschaft und Öffentlichkeit frei zugänglich zu machen. Eines der zentralen Ziele dieses Konzeptes besteht darin, die Vereinbarung zur Verknüpfung bewährter Forschungsdateninfrastrukturen einzelner DAM-Mitgliedseinrichtungen, zur Öffnung für die gesamte Deutsche Meeresforschung und zu einem gemeinsamen Betriebskonzept zu treffen. Dafür sollten sich die DAM-Mitgliedseinrichtungen auf ein Konzept verständigen, das ihre institutionelle Souveränität im Umgang mit Forschungsdaten wahrt und gleichzeitig auf die Vereinheitlichung von Prozessen und Mindeststandards hinwirkt