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| Titel |
Strangers in Paradise: The biogeographic range expansion of the foraminifera Amphistegina in the Mediterranean Sea |
| VerfasserIn |
M. R. Langer, A. E. Weinmann, D. Rödder, S. Lötters |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250063482
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| Zusammenfassung |
| Species distribution models (SDMs) have become important tools in biogeography and
biodiversity research over the last decades. They are mainly based on the fundamental niche
concept and allow the correlative prediction of species’ potential distributional ranges by
combining occurrence records with information on environmental (e.g. climatic) conditions.
The generated environmental envelope of a species is projected into geographic space, thus
defining areas of adequate habitat suitability. Here we apply a species distribution model
(SDM) to assess potential range expansions of Amphistegina spp. in the Mediterranean Sea
under current und future climate conditions. The model uses an environmental
envelope of information from localities where amphisteginids are currently known to
occur.
Amphisteginid foraminifers are a group of circumtropically distributed, larger
symbiont-bearing, calcareous foraminifera that have a well-documented record as detectors
of historical climate change. They are currently expanding their biogeographic range in the
Mediterranean Sea and rapidly progressing northwestward, closely approaching the Adriatic
and the Tyrrhenian Sea. The shift in range locally leads to profound ecological changes where
amphisteginids have become the dominant species along entire stretches of coastline. Mass
deposits of amphisteginids reflect an increased carbonate production and reduced assemblage
diversity, and these are likely to trigger major changes in ecosystem functioning.
It is anticipated that the ongoing warming trend will convey the northwestward
migration of amphisteginid foraminifers. Our model indicates that further warming is
likely to cause a northwestward range extension and predicts dispersal through
the straits of Sicily, Messina and Otranto into the Tyrrhenian and Adriatic Sea.
Rapid proliferation and the extreme abundances of amphisteginid foraminifera
affect the dynamic equilibrium of established foraminiferal biotas. In the eastern
Mediterranean, diverse assemblages of shallow-water foraminifera are being replaced
by monocultures of rapidly spreading amphisteginids. Climate change, through
long-term temperature increase, will continue to promote the homogenization of
foraminiferal fauna, ultimately leading to a meridionalization of the Mediterranean Sea. |
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