Biogeography of Mediterranean Hotspot
Biodiversity Re-Evaluating the 'Tertiary
Relict' Hypothesis of Macaronesian Laurel
Forests

Identifier

Title

Biogeography of Mediterranean Hotspot
Biodiversity Re-Evaluating the 'Tertiary
Relict' Hypothesis of Macaronesian Laurel
Forests

Subject

Description

The Macaronesian laurel forests (MLF) are dominated by trees with a laurophyll habit comparable to evergreen humid forests which were scattered across Europe and the Mediterranean in the Paleogene and Neogene. Therefore, MLF are traditionally regarded as an old, 'Tertiary relict' vegetation type. Here we address the question if key taxa of the MLF are relictual. We evaluated the relict hypothesis consulting fossil data and analyses based on molecular phylogenies of 18 representative species. For molecular dating we used the program BEAST, for ancestral trait reconstructions BayesTraits and Lagrange to infer ancestral areas. Our molecular dating showed that the origins of four species date back to the Upper Miocene while 14 originated in the Plio-Pleistocene. This coincides with the decline of fossil laurophyllous elements in Europe since the middle Miocene. Ancestral trait and area reconstructions indicate that MLF evolved partly from pre-adapted taxa from the Mediterranean, Macaronesia and the tropics. According to the fossil record laurophyllous taxa existed in Macaronesia since the Plio- and Pleistocene. MLF are composed of species with a heterogeneous origin. The taxa dated to the Pleistocene are likely not 'Tertiary relicts'. Some species may be interpreted as relictual. In this case, the establishment of most species in the Plio-Pleistocene suggests that there was a massive species turnover before this time. Alternatively, MLF were largely newly assembled through global recruitment rather than surviving as relicts of a once more widespread vegetation. This process may have possibly been triggered by the intensification of the trade winds at the end of the Pliocene as indicated by proxy data.

Source

PLoS ONE. Vol. 10 Issue 7, p1-17. 17p.

Publisher

PLoS ONE. Vol. 10 Issue 7, p1-17. 17p.

Date

7/14/2015

Format

PDF

Language

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Files

Biogeography of Mediterranean Hotspot.pdf

Citation

Kondraskov, Paulina Schütz, Nicole Schüßler, Christina de Sequeira, Miguel Menezes Guerra, Arnoldo Santos Caujapé-Castells, Juli Jaén-Molina, Ruth Marrero-Rodríguez, Águedo Koch, Marcus A. Linder, Peter Kovar-Eder, Johanna Thiv, Mike , “Biogeography of Mediterranean Hotspot
Biodiversity Re-Evaluating the 'Tertiary
Relict' Hypothesis of Macaronesian Laurel
Forests,” Uwekind Resource Centre, accessed June 22, 2024, http://library.uwekind.com/items/show/396.