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| Titel |
Native Dreissena freshwater mussels in the Balkans: in and out of ancient lakes |
| VerfasserIn |
T. Wilke, R. Schultheiß, C. Albrecht, N. Bornmann, S. Trajanovski, T. Kevrekidis |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 10 ; Nr. 7, no. 10 (2010-10-11), S.3051-3065 |
| Datensatznummer |
250005008
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| Publikation (Nr.) |
 copernicus.org/bg-7-3051-2010.pdf |
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| Zusammenfassung |
The Balkans is a biogeographically highly diverse region and a worldwide
hotspot of endemic freshwater diversity. A substantial part of this
diversity is attributed to well recognized and potential ancient lakes in
its southwestern part. However, despite considerable research efforts,
faunal relationships among those lakes are not well understood. Therefore,
genetic information from native representatives of the mussel genus
Dreissena is here used to test the biogeographical zonation of the southwestern
Balkans, to relate demographic changes to environmental changes, to assess
the degree of eco-insularity, to reconstruct their evolutionary history, and
to explore the potential of native taxa for becoming invasive.
Phylogeographical and population genetic analyses indicate that most studied
populations belong to two native species: D. presbensis (including the distinct genetic
subgroup from Lake Ohrid, "D. stankovici") and D. blanci. In addition, the first confirmed
record of invasive D. polymorpha in the southwestern Balkan is presented.
The distribution of native Dreissena spp. generally coincides with the
biogeographical zonations previously suggested based on fish data. However,
there is disagreement on the assignment of the ancient lakes in the area to
respective biogeographical regions. The data for Lake Ohrid are not
conclusive. A closer biogeographical connection to lakes of the Vardar region
and possibly the northern Ionian region is, however, suggested for Lake
Prespa.
The reconstruction of the evolutionary history of Dreissena spp. suggests that
populations underwent demographic and spatial expansions in the recent
past. Expansions started around 320 000–300 000 years ago in
"D. stankovici", 160 000–140 000 years ago in D. blanci, and 110 000–70 000 years ago in D. presbensis.
These time frames are discussed within the context of available
paleogeological data for lakes Ohrid and Prespa. It is suggested that
regional environmental changes may have had pronounced effects on the
population histories of native Dreissena spp., though the high buffer capacity of Lake
Ohrid may have lessened these effects in "D. stankovici". In addition, local events
influencing individual lakes had very likely considerable effects on the
demographic histories of Dreissena spp. as well. The observed patterns of immigration
and emigration in and out of ancient lakes may suggest that limited gene flow
enabled the survival of few isolated subpopulations and that later on
eco-insularity (selective advantages of locally adopted groups) may have
prevented excessive hybridization and sympatry of closely related taxa.
As for the potential invasiveness of native Dreissena spp., the inferred spatial
expansions are not human-mediated and all taxa still appear to be restricted
to their native ranges. A concern, however, is that today D. presbensis and D. blanci also occur
in artificial water bodies, and that invasive D. polymorpha has reached the area. |
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