Network biogeography of a complex island system: the Aegean Archipelago revisited

Abstract

Aim The Aegean Archipelago has been the focal research area for identifying and testing several ecological and evolutionary patterns, yet its biogeographical subdivision has been somewhat overlooked, with the processes driving the assembly of the Aegean island plant communities still remaining largely unclear. To bridge this gap, we identify the biogeographical modules (highly linked subgroups of islands and plant taxa) within the Aegean Archipelago.Location The Aegean Archipelago, Greece. MethodsWe used a network approach to detect island biogeographical roles and modules, based on a large and detailed database including 1498 Aegean endemic and subendemic plant taxa distributed on 59 Aegean Islands and five adjacent mainland areas. ResultsThe Aegean was divided into six biogeographical modules; the network was significantly modular. None of the modules displayed all four possible biogeographical roles (connectors, module hubs, network hubs, peripherals). Six new biogeographical regions in the Aegean were identified.Main conclusions The borders of the six biogeographical regions in the Aegean correspond well to the region's palaeogeographical evolution from the middle Miocene to the end of the Pleistocene. The Central Aegean acts as an ecogeographical filter for the distribution of several plant lineages across the Aegean Sea, while there seems to be a N-S-oriented biogeographical barrier in the Aegean corresponding to the palaeogeographical situation during the middle Ionian. These biogeographical barriers have been fundamental for both plants and animals.

Hybridization‐facilitated genome merger and repeated chromosome fusion after 8 million years

“…9.32 Ma, which is when Karpathos and Rhodos were still connected to the Anatolian mainland. Karpathos has become completely isolated from Rhodos during the late Pliocene (3.6–2.58 Ma; Beerli et al ., ; Kougioumoutzis et al ., ). The most plausible scenario includes the divergence of both Ricotia species on the Anatolian mainland, the migration of R. isatoides to present‐day Karpathos and the extinction of the mainland populations.…”

“…Cellinese et al ., ; Crowl et al ., ; Sfenthourakis and Triantis, ), and this landmass existed at the time of the purported origin of Ricotia , dated between 20.7 and 14.6 Ma. Approximately 12 Ma, as the waters of the Mediterranean innundated Ägäis, today's Crete was separated from Karpathos’ island complex, and by 8 Ma the Cretan group of islands was isolated by the sea (Kougioumoutzis et al ., ; Sfenthourakis and Triantis, ). During the Messinian Salinity Crisis (MSC; 5.93–5.33 Ma), when the whole Mediterranean basin desiccated, the Aegean Islands and Asia Minor were connected by numerous land bridges, facilitating dispersal events; however, Crete was surrounded by saline deserts or saline/hypersaline lakes during the MSC (Kougioumoutzis et al ., ), hampering dispersal events from and to Crete.…”

Multi-Level Characterization of Eggplant Accessions from Greek Islands and the Mainland Contributes to the Enhancement and Conservation of this Germplasm and Reveals a Large Diversity and Signatures of Differentiation between both Origins

“…Greece lies at the southernmost part of the Balkan peninsula, at a crossroads between Europe, Asia, and Africa. The country is noted for its high species diversity, the extensive coverage of natural and semi-natural habitats, and many island complexes in the Archipelagos of Aegean Sea and the Ionian Sea [1]. Islands are natural laboratories for the study of the evolution and ecology of wild plants and endemisms [2][3][4].…”

A new Hypericum (sect. Drosocarpium, Hypericaceae) from the Cyclades Islands (Greece)

“…Furthermore, the two species inhabit similar dry habitats, while H. perfoliatum grows in ± wet places. However, this conclusion is incongruent with the general palaeogeographical history of the Aegean, as the main plant biogeographical connection of the central Aegean area is with with mainland Greece, while the connection between the central Aegean and Crete is much more weak (Kougioumoutzis et al 2017).…”