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| Titel |
Spatially explicit analysis of gastropod biodiversity in ancient Lake Ohrid |
| VerfasserIn |
T. Hauffe, C. Albrecht, K. Schreiber, K. Birkhofer, S. Trajanovski, T. Wilke |
| 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 ; 8, no. 1 ; Nr. 8, no. 1 (2011-01-26), S.175-188 |
| Datensatznummer |
250005353
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| Publikation (Nr.) |
 copernicus.org/bg-8-175-2011.pdf |
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| Zusammenfassung |
The quality of spatial analyses of biodiversity is improved by (i) utilizing
study areas with well defined physiogeographical boundaries, (ii) limiting
the impact of widespread species, and (iii) using taxa with heterogeneous
distributions. These conditions are typically met by ecosystems such as
oceanic islands or ancient lakes and their biota. While research on ancient
lakes has contributed significantly to our understanding of evolutionary
processes, statistically sound studies of spatial variation of extant
biodiversity have been hampered by the frequently vast size of ancient
lakes, their limited accessibility, and the lack of scientific
infrastructure. The European ancient Lake Ohrid provides a rare opportunity
for such a reliable spatial study. The comprehensive horizontal and vertical
sampling of a species-rich taxon, the Gastropoda, presented here, revealed
interesting patterns of biodiversity, which, in part, have not been shown
before for other ancient lakes.
In a total of 284 samples from 224 different locations throughout the Ohrid
Basin, 68 gastropod species, with 50 of them (= 73.5%) being endemic,
could be reported. The spatial distribution of these species shows the
following characteristics: (i) within Lake Ohrid, the most frequent species
are endemic taxa with a wide depth range, (ii) widespread species (i.e.
those occurring throughout the Balkans or beyond) are rare and mainly occur
in the upper layer of the lake, (iii) while the total number of species
decreases with water depth, the proportion of endemics increases, and (iv)
the deeper layers of Lake Ohrid appear to have a higher spatial homogeneity
of biodiversity. Moreover, gastropod communities of Lake Ohrid and its
feeder springs are both distinct from each other and from the surrounding
waters. The analysis also shows that community similarity of Lake Ohrid is
mainly driven by niche processes (e.g. environmental factors), but also by
neutral processes (e.g. dispersal limitation and evolutionary histories of
species). For niche-based mechanisms it is shown that large scale effects
such as type of water body or water depth are mainly responsible for the
similarity of gastropod communities, whereas small scale effects like
environmental gradients affect gastropod compositions only marginally. In
fact, neutral processes appear to be more important than the small scale
environmental factors, thus emphasizing the importance of dispersal
capacities and evolutionary histories of species. |
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