My bachelor thesis
structure of European sculpin (Cottus
the contact area of Danube, Odra and Elbe river basins
In this study, an allozyme survey was used to compare populations of Cottus
gobio across the three main drainage systems Elbe, Danube and Odra in
area of the Czech Republic where all three drainages are in close contact. The
results of former studies in Germany and the fact that C. gobio is non-migratory, bottom-dwelling species led us to expect
larger differences among populations from different drainage systems.
The analysis showed larger differentiation between populations of Odra
drainage system on the one side and Elbe and Danube systems on the other one.
The mean value of genetic distances found out in our area between the
populations of Elbe and Danube basins was lower than those between the same
basins in Germany. Although the most different populations were those from Odra
River basin, the differences (and thereby the divergence time calculated from
genetic distances) were also smaller than I expected according to different
geographic history of this area and according to hypothesis, that C.
gobio has colonised this area via different (eastern) colonisation route and
so has diverged earlier. Smaller differences could be explained by mixing
populations from different drainages via stream captures in bordering areas in
the evolutionary history. Different colonisation route could be the reason of
larger differentiation of Odra basin populations but supposed secondary contact
could lower the values to the found level.
study was supported by the Grant Agency AS CR (S 504511) and by an internal
grant of IAPG (ÚFG/00/13).
Abstract and topic of my master thesis
OG THE ALPS AS A BARRIER TODISPERSAL IN COLD-ADAPTED FRESHWATER FISHES:
PHYLOGEOGRAPHIC HISTORY AND TAXONOMIC STATE OF THE BULLHEAD (COTTUS GOBIO)
IN THE ADRIATIC FREWSHWATER DRAINAGE
study dealed with phylogeographic history of Cottus populations in the
southern Europe with main focus on the perialpine area, Dinaric Mountains and
rivers of the Northern Adriatic freshwater drainage. The aim of the study is to
answer the questions of the highest European Mountains - the Alps - as a
geographical barrier to dispersal of cold - adapted freshwater fish Cottus
gobio. It should answer the question of origin of Northern Adriatic
populations of Cottus, their relationship with Cottus from
adjacent river basins and their taxonomic status as the area of our interest
covers the distribution area of a doubtfull species Cottus ferrugineus.
The freshwater faunas
of the Italian peninsula are isolated from the rest of Europe by the geographic
barrier of the Alps and consequently have developed many endemic forms and
contain few non-endemic species. However, some non-endemics may either represent
recent invaders of the Adriatic basin or cryptic endemic species. To test these
two hypotheses against each other, we studied the origin and phylogenetic
relationships of bullheads, cold adapted freshwater .shes of the genus Cottus,
from both sides of the Alps and Dinaric Mountains. From the Adriatic basin,
Cottus ferrugineus (Heckel and Kner, 1858) was described as an endemic species,
but the present analyses of sequences of the complete mitochondrial control
region of 146 individuals from 43 localities showed no major di.erentiation
between bullheads from both sides of the Alps. The very low diversi.cation
between representatives across the Alps suggests active transfers of haplotypes
across this geographic barrier from the glacial cycles up to recent times. The
transfers are most likely based on stream capture, since the cold-adapted
bullhead is able to colonise the highest stretches of the water courses. No
other freshwater .sh in Europe is known to have experienced such an extensive
gene .ow across the highest European Mountains. In contrast, the Dinaric
Mountains seem to have been a much more e.ective barrier between the Danube and
the Adriatics. Our data reject the hypothesis of C. ferrugineus as an endemic
species in the whole Adriatic drainage.
thanks I owe to J. Bohlen, for his constant help throughout the whole study in
all respects - collecting material, interpretation of data as well as a
psychological support. On
the next place, my thanks belong to J. Freyhof as to initiator of this study and
author of its original idea. Next,
I would like to express my thanks
to G. Delmastro, J. Freyhof, L. Kalous, M. Kottelat, M. Mrakovcic, A. Nolte, H. Persat
& J. Schöffmann for help in the field, for provision of
samples or for help with obtaining the samples. Very helpful advises regarding
the laboratory work and the data analyses came from I. Doadrio, C. Cunha, A. Marchodom,
A. Nolte, A.
Perdices & K-E. Witte. Earlier drafts of the manuscript improved much due to
the critical comments of P. Koltík, M. Macholán, P. Rab V. Slechta.
V., J. Bohlen, J. Freyhof, H. Persat, G.B. Delmastro (in press): The Alps as
barrier to dispersal in cold-adapted freshwater fishes? Phylogeographic history
and taxonomic status of the bullhead in the Adriatic freshwater drainage. Mol.Phyl.Evol.,