Browsing by Author "Dirkse, Gerard"
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- Climate threat on the Macaronesian endemic bryophyte floraPublication . Patiño, Jairo; Mateo, Rubén G.; Zanatta, Florian; Marquet, Adrien; Aranda, Silvia C.; Borges, Paulo A. V.; Dirkse, Gerard; Gabriel, Rosalina; Gonzalez-Mancebo, Juana M.; Guisan, Antoine; Muñoz, Jesús; Sim-Sim, Manuela; Vanderpoorten, AlainOceanic islands are of fundamental importance for the conservation of biodiversity because they exhibit high endemism rates coupled with fast extinction rates. Nowhere in Europe is this pattern more conspicuous than in the Macaronesian biogeographic region. A large network of protected areas within the region has been developed, but the question of whether these areas will still be climatically suitable for the globally threatened endemic element in the coming decades remains open. Here, we make predictions on the fate of the Macaronesian endemic bryophyte flora in the context of ongoing climate change. The potential distribution of 35 Macaronesian endemic bryophyte species was assessed under present and future climate conditions using an ensemble modelling approach. Projections of the models under different climate change scenarios predicted an average decrease of suitable areas of 62–87% per species and a significant elevational increase by 2070, so that even the commonest species were predicted to fit either the Vulnerable or Endangered IUCN categories. Complete extinctions were foreseen for six of the studied Macaronesian endemic species. Given the uncertainty regarding the capacity of endemic species to track areas of suitable climate within and outside the islands, active management associated to an effective monitoring program is suggested.
- Climate-driven vicariance and long-distance dispersal explain the Rand Flora pattern in the liverwort Exormotheca pustulosa (Marchantiophyta)Publication . Rodrigues, Ana S. B.; Martins, Anabela; Garcia, César Augusto; Sérgio, Cecília; Porley, Ron; Fontinha, Susana; González-Mancebo, Juana M.; Gabriel, Rosalina; Phephu, Nonkululo; Van Roy, Jacques; Dirkse, Gerard; Long, David; Stech, Michael; Patiño, Jairo; Sim-Sim, ManuelaThe ‘Rand flora’ is a biogeographical disjunction which refers to plant lineages occurring at the margins of the African continent and neighbouring oceanic archipelagos. Here, we tested whether the phylogeographical pattern of Exormotheca pustulosa Mitt. was the result of vicariance induced by past climatic changes or the outcome of a series of recent long-distance dispersal events. Two chloroplast markers (rps4-trnF region and psbA-trnH spacer) and one nuclear marker (ITS2) were analysed. Phylogenetic and phylogeographical relationships were inferred as well as divergence time estimates and ancestral areas. Exormotheca possibly originated in Eastern Africa during the Late Oligocene/Early Miocene while Exormotheca putulosa diversified during the Late Miocene. Three main E. pustulosa groups were found: the northern Macaronesia/Western Mediterranean, the South Africa/Saint Helena and the Cape Verde groups. The major splits among these groups occurred during the Late Miocene/Pliocene; diversification was recent, dating back to the Pleistocene. Climate-driven vicariance and subsequent long-distance dispersal events may have shaped the current disjunct distribution of E. pustulosa that corresponds to the Rand Flora pattern. Colonization of Macaronesia seems to have occurred twice by two independent lineages. The evolutionary history of E. pustulosa populations of Cape Verde warrants further study.
- The moss Homalothecium mandonii as a model for assessing bryophyte response to climate change in MacaronesiaPublication . Vanderpoorten, Alain; Mateo, Rúben G.; Sim-Sim, Manuela; Ruas, Sara; Dirkse, Gerard; Gabriel, Rosalina; Borges, Paulo A. V.; González-Mancebo, Juana M.; Calvo, Silvia; Patiño, JairoOs briófitos possuem características ecofisiológicas e biológicas únicas que os tornam excelentes indicadores das alterações climáticas. Com o auxílio de modelos de nicho ecológico, analisou-se em que medida as alterações climáticas podem afectar a brioflora endémica da Macaronésia, em particular o musgo Homalothecium mandonii. A projecção do nicho actual desta espécie sobre as camadas macroclimáticas da última glaciação máxima, indicam que a área de distribuição da espécie seria superior em cerca de 200% relativamente à área actual. As projecções paleoclimáticas identificam ainda que a região noroeste de África e a Península Ibérica possuem condições climáticas favoráveis ao desenvolvimento desta espécie, sugerindo que se poderá tratar de um paleoendemismo. Em conformidade com observações prévias, os resultados obtidos sugerem que a Macaronésia representa um refúgio para as espécies actualmente extintas de zonas continentais. No entanto, as projecções do nicho climático da espécie para o futuro, predizem um declínio da área favorável de 29-53% em 2080. Tais predicções sugerem então que o papel de refúgio climático que a Macaronésia tem desempenhado se encontra fortemente ameaçado como resultado das alterações climáticas em curso.