Browsing by Author "González-Mancebo, Juana M."
Now showing 1 - 6 of 6
Results Per Page
Sort Options
- 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.
- A comparison of bryophyte diversity in the Macaronesian Islands: island versus habitat approachPublication . González-Mancebo, Juana M.; Gabriel, Rosalina; Otto, Rüdiger; Sim-Sim, Manuela; Luís, Leena Margarida; Sérgio, Cecília; Garzón-Machado, Víctor; Aranda, Silvia C.; Capelo, Jorge; Vanderpoorten, AlainIn this paper, we present a comparison of richness patterns and floristic similarity for bryophytes in the five most important altitudinal habitat types in the Macaronesian islands. We evaluate the importance of different factors discussed in the literature in predicting species diversity applying the traditional island approach and within the framework of the new habitat approach, including area, isolation, climatic factors, geological age and human influence. From the analysis of patterns of bryophyte species distribution for selected habitats across islands and archipelagos, we specifically test the hypothesis that (i) floristic similarity is primarily determined by climatic factors, but not by geographical distance due to high dispersal ability in this species group and (ii) bryophyte richness is best predicted by area, but not by geological age of the habitat due to very low endemicity or speciation rate and high colonization rate.
- Distribution patterns of Leucodon species in Macaronesia, with special reference to the Canary IslandsPublication . González-Mancebo, Juana M.; Patiño, Jairo; Werner, Olaf; Gabriel, Rosalina; Ros, Rosa M.The genus Leucodon is represented in Macaronesia by three species, L. sciuroides, L. canariensis and L. treleasei, the latter two being endemic to this region. An analysis of distribution, frequency and habitats for all three species in this region shows singular patterns for each species, mainly related to habitat conservation and type of habitat. Leucodon canariensis is the most restricted species as regards habitat conditions, with a confirmed presence only on Madeira and the Canary Islands, although more abundant in the latter. Leucodon treleasei exhibits the widest habitat amplitude, especially on Madeira, and it is present in all three northern archipelagos. Leucodon sciuroides is the most tolerant species to aridity and is mainly found on Madeira and the Canary Islands, although its occurrence was confirmed in all the Macaronesian archipelagos.
- 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.
- Scaling a- and b-diversity : bryophytes along an elevational gradient on a subtropical oceanic Island (La Palma, Canary Islands)Publication . Hernández-Hernández, Raquel; Borges, Paulo A. V.; Gabriel, Rosalina; Rigal, François; Ah-Peng, Claudine; González-Mancebo, Juana M.QUESTIONS: We addressed three questions: (1) what is the variation of a- and b-diversity of bryophyte communities across spatial scales in an elevational gradient; (2) is spatial variation characteristic of different phylogenetic (mosses/ liverworts) and/or ecological groups (terrestrials/epiphytes); and (3) what is the CONTRIBUTION of species richness and species replacement (true turnover) to b-diversity along the elevational gradient? LOCATION: La Palma, Canary Islands, Spain. METHODS: An elevational transect spanning 0–2200 m a.s.l was sampled at altitudinal intervals of ca. 200 m, two 10 m 9 10 m plots were established at each elevation and inside each plot three 2 m 9 2 m quadrats were randomly selected. Within each quadrat, bryophytes were sampled in three replicate microplots of 10 cm 9 5 cm, for each substrate: soil, rocks, leaves, humus, decaying wood and tree trunks at three heights. We evaluated a- and b-diversity at plot and elevational level for all bryophytes and for phylogenetic and ecological Groups. Values of b-diversity were further decomposed into replacement and richness differences. We tested the relationship between a- and b-diversity and elevation using linear models with and without a quadratic term (elevation2) in an AICc-based framework. RESULTS: A total of 121 species were recorded along the transect. Alpha-diversity showed a hump-shaped pattern with elevation for all bryophytes, liverworts and epiphytic species, however, terrestrial species and mosses displayed no clear pattern. Species replacement was the main driver of b-diversity for all bryophytes and also for mosses and terrestrial species, and at different scales (elevational belt and quadrat). The contribution of species replacement increased with elevation, except for epiphytes and terrestrials. CONCLUSIONS: Our study contributes towards an understanding of the spatial organization of bryophyte diversity at different scales along an insular elevational gradient. We showed that bryophyte diversity was mostly influenced by species replacement at the largest scale. The observed differences in b-diversity decomposition between bryophyte phylogenetic and ecological groups could be dependent on climatic conditions and substrate availability. The strong differences observed along the elevational gradient related to true turnover are especially important in the current global change scenario.
- The taxonomic status and the geographical relationships of the Macaronesian endemic moss Fissidens luisieri (Fissidentaceae) based on DNA sequence dataPublication . Werner, Olaf; Patiño, Jairo; González-Mancebo, Juana M.; Gabriel, Rosalina; Ros, Rosa M.The taxonomic identity and the geographical relationships of the Macaronesian endemic moss Fissidens luisieri have been studied using the chloroplast trnGUCC intron, the spacer between trnM and trnV, together with the trnV intron and ITS1 and ITS2 sequences. A comparison of F. luisieri with the most closely related species, F. serrulatus, from the same geographical areas reveals that the distribution pattern of F. serrulatus and F. luisieri, rather than their morphological differences, explains the observed differences. Therefore, we conclude that both names correspond to the same species. One of the primers for the chloroplast trnGUCC intron and both primers for the trnM–trnV region were designed for this study; they can all be widely used within bryophytes because they provide similar degrees of variability as other regions of the chloroplast genome such as the atpB–rbcL intergenic spacer.