Browsing by Author "Johnson, Markes E."
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- Palaeobiogeography of NE Atlantic archipelagos during the last Interglacial (MIS 5e): a molluscan approach to the conundrum of Macaronesia as a marine biogeographic unitPublication . Melo, Carlos S.; Marques da Silva, Carlos; Scarponi, Daniele; Martín-González, Esther; Rólán, Emilio; Rojas, Alejandra; Martinez, Sergio; Silva, Luís; Johnson, Markes E.; Cristina Rebelo, Ana; Baptista, Lara; Voelker, Antje; Ramalho, Ricardo S.; Ávila, Sérgio P.In order to understand the complex evolutionary processes and patterns that explain current island biodiversity, large datasets and long-term analysis are required. The Last Interglacial (LIG) was one of the warmest interglacials during the last million years. How species mobility changed during this period in the Macaronesia geographical region has long intrigued scientists. It is well established that the northward range expansion of tropical species occurred in the Macaronesian geographical region, but as a marine biogeographic unit, the term "Macaronesia" has not gained a consensus among the scientific community. For the first time, a thoroughly revised and updated checklist is presented for shallow-water marine molluscs from the Atlantic and Mediterranean during the LIG. Based on these wide ranging data, the status of Macaronesia as a marine biogeographic unit during the LIG was examined and our scientific understanding of how this unit evolved is improved. The analysis shows that during the LIG, the molluscan faunas of the Canary and Cabo Verde archipelagos were part of the same tropical Late Pleistocene Mediterranean West-African Province, whereas those in the Azores, Madeira and Selvagens archipelagos would be included in the subtropical Late Pleistocene French-Iberian Province. This contrasts with the present-day scenario, where the subtropical/warm temperate Azores and "Webbnesia" marine ecoregions (Lusitanian province) are biogeographically distinct from the Cabo Verde biogeographic subprovince, which in turn belongs to the West African Tropical biogeographic province. A further analysis of the coherence of "Macaronesia" as a marine biogeographical unit was accomplished by coupling Pliocene, LIG, and present-day data, showing that the term "Macaronesia", and for the marine realm, should only be used in a geographical connotation.
- Range expansion of tropical shallow-water marine molluscs in the NE Atlantic during the last interglacial (MIS 5e): Causes, consequences and utility of ecostratigraphic indicators for the Macaronesian archipelagosPublication . Melo, Carlos S.; Martín-González, Esther; da Silva, Carlos M.; Galindo, Inés; González-Rodríguez, Alberto; Baptista, Lara; Rebelo, A. Cristina; Madeira, Patrícia; Voelker, Antje; Johnson, Markes E.; Arruda, Samuel A.; Ávila, Sérgio P.Controlled by ecological and physical factors, marine species distribution may vary due to global climatic changes that result from range expansion or contraction (the latter caused by local disappearances, i.e., extirpations). Spanning from 13 degrees to 39 degrees N, the Macaronesian region encompasses five archipelagos located within warm-temperate to tropical climatic zones and influenced by a surface water current regime that favours a N-S range expansion of marine species. The extensive and well-preserved Macaronesian fossil record makes these islands excellent candidates for evolutionary studies. It documents a northward range expansion of tropical species with a Cabo Verdean-Mauritanian-Senegalese biogeo-graphic provenance during the Last Interglacial (LIG). For the first time, a thorough revision and update of marine molluscs' checklist from the Macaronesian archipelagos for the LIG is presented. On this basis, we hypothesize that the range expansion occurred during the last phase of glacial Termination 2 and was enhanced by ephemeral sea surface currents that created windows of opportunity for the long-distance dispersal of marine species along sweepstake routes. During these short intervals of time, numerous tropical and subtropical species expanded their geographic range northwards, towards what today are subtropical and temperate archipelagos. Simultaneously, however, a smaller number of northern species expanded their ranges southward, some reaching Cabo Verde. This work yields a set of 24 mollusc "ecostratigraphic indicators" (10 bivalve and 14 gastropod species) that are important to identify fossiliferous deposits from the Last Interglacial epoch in Macaronesian archipelagos. Longitudinal range expansions from West African shores to the Cabo Verde archipelago and the Canary Islands were also detected. These are related to coeval weaker upwelling systems which now constitute effective barriers for the exchange of species/individuals between continental and insular shores (e.g., Senegal/Cabo Verde; Morocco/Canaries). Finally, an ecological filter-effect also existed, which we associate with the increasingly longer distances to cover, as many of the most typical representatives of the warm water fauna with Cabo Verde/Senegalese affinities failed to reach the northern Azores and Madeira archipelagos. (C) 2022 Elsevier Ltd. All rights reserved.
- Reply to the comment by Meco et al. on “Range expansion of tropical shallow-water marine molluscs in the NE Atlantic during the last interglacial (MIS 5e): Causes, consequences and utility of ecostratigraphic indicators for the Macaronesian archipelagos”Publication . Melo, Carlos S.; Martín-González, Esther; da Silva, Carlos M.; Galindo, Inés; González-Rodríguez, Alberto; Baptista, Lara; Rebelo, A. Cristina; Madeira, Patrícia; H L Voelker, Antje; Johnson, Markes E.; Arruda, Samuel A.; Ávila, Sérgio P.It was with much interest that we read the comment made by Meco et al. (2022), regarding our work on “Range expansion of tropical shallow-water marine molluscs in the NE Atlantic during the last interglacial (MIS 5e): Causes, consequences and utility of ecostratigraphic indicators for the Macaronesian archipelagos”. We welcome the discussion generated by our paper and appreciate the recognition of its complexity and broad scope. In our opinion, the arguments offered by Meco et al. (2022) do not contradict our conclusions. Nevertheless, we take this opportunity to address their critiques regarding our list of “ecostratigraphic indicators” and parts of our hypothesized range expansions. Meco et al.
- Restructuring of the ‘Macaronesia’ biogeographic unit: a marine multi-taxon biogeographical approachPublication . Freitas, Rui; Romeiras, Maria; Silva, Luís; Cordeiro, Ricardo; Madeira, Patrícia; González, José Antonio; Wirtz, Peter; Falcón, Jesús M.; Brito, Alberto; Floeter, Sergio R.; Afonso, Pedro; Porteiro, Filipe; Viera-Rodríguez, María Ascensión; Neto, Ana Isabel; Haroun, Ricardo; Farminhão, João N. M.; Rebelo, Ana Cristina; Baptista, Lara; Melo, Carlos S.; Martínez, Alejandro; Núñez, Jorge; Berning, Björn; Johnson, Markes E.; Ávila, Sérgio P.The Azores, Madeira, Selvagens, Canary Islands and Cabo Verde are commonly united under the term "Macaronesia". This study investigates the coherency and validity of Macaronesia as a biogeographic unit using six marine groups with very different dispersal abilities: coastal fishes, echinoderms, gastropod molluscs, brachyuran decapod crustaceans, polychaete annelids, and macroalgae. We found no support for the current concept of Macaronesia as a coherent marine biogeographic unit. All marine groups studied suggest the exclusion of Cabo Verde from the remaining Macaronesian archipelagos and thus, Cabo Verde should be given the status of a biogeographic subprovince within the West African Transition province. We propose to redefine the Lusitanian biogeographical province, in which we include four ecoregions: the South European Atlantic Shelf, the Saharan Upwelling, the Azores, and a new ecoregion herein named Webbnesia, which comprises the archipelagos of Madeira, Selvagens and the Canary Islands.