P. Leukart et D. Mollenhauer, STUDIES ON ALGAL DRIFT IN A SMALL SOFT-WATER STREAM IN THE SPESSART MOUNTAINS, GERMANY, Nova Hedwigia, 65(1-4), 1997, pp. 431-442
Bimonthly drift samples were taken over the course of a year at three
stations in a small soft-water stream, the Bieber (Spessart mountains,
Germany), which has been under observation for many years. The statio
ns were located upstream and downstream of the first village, and upst
ream of the mouth. 29 algal taxa (excluding diatoms and some unicellul
ar green algae) were identified, (3 Rhodophyta, 16 Chlorophyta, 2 Chry
sophyceae, 2 Tribophyceae, 5 Cyanophyceae, 1 Cryptophycae). There were
no differences in the total number of taxa in the drift samples from
the three stations, but the taxal composition varied. Taxa detected in
the drift samples were compared to those growing at the stations. At
station 2 and 3 the number of taxa in the drift was twice as high as t
he number growing at the stations. Some taxa were found more frequentl
y at one rather than at another station. With respect to seasonal occu
rrence, some taxa were found all year round whereas others occurred on
ly once. The number of taxa found only once increased from station 1 t
o station 3. Coincidence in taxa composition was low between the three
stations but higher between their drift samples. This points to the p
ossibility that taxa which were present in the drift may not be able t
o establish themselves in all parts of the stream. Station 2 and 3 res
embled each other in taxa composition and seasonal occurrence in the d
rift samples, whereas station 1 was different. One reason for the simi
larity of stations 2 and 3 might be water quality. This part of the Bi
eber is impaired by waste water, whereas the water is pure at station
1.