ISSN 1067-4136, Russian Journal of Ecology, 2008, Vol. 39, No. 3, pp. 193–197. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © E.I. Filinova, Yu.A. Malinina, G.V. Shlyakhtin, 2008, published in Ekologiya, 2008, No. 3, pp. 206–210.
The construction of reservoirs creates new living
conditions for hydrobionts, which leads to signiﬁcant
qualitative changes in their fauna. An important role in
the formation of the benthic community belongs to
“bioecological provision,” i.e., to the presence of a
complex of organisms characteristic of the environment
historically formed in this region that, due to their eco-
logical properties, are capable of living and reproduc-
ing in the newly created water body (Zhadin, 1947).
The faunistic complex of large lowland reservoirs of the
Volga cascade has been formed under the effect of mea-
sures to restore the bottom fauna in order to improve
food supply to benthophagous ﬁshes.
Changes in the bottom fauna of the Volgograd
Reserve from the moment of its construction to the
present time have been analyzed on the basis of our
own studies on the zoobenthos (1979–2004) and pub-
lished data (Belyavskaya, 1965; Belyavskaya et al.,
1969; Konstantinov, 1969; Nechvalenko, 1976, 1977).
Species of invertebrate hydrobionts were identiﬁed by
keys to freshwater invertebrates (
The Volgograd Reservoir (ﬁlled between 1958 and
1960) is a very large reservoir of the valley type. On the
basis of geomorphological and hydrological features,
three segments are distinguished in it: the upper seg-
ment (Balakovo–Saratov) of a riverine type, the transi-
tional middle segment (Saratov–Kamyshin), and the
lower segment (Kamyshin–Hydroelectric Power Plant)
of a lacustrine type. The reservoir has a seasonal type of
ﬂow discharge regulation; a high index of replacement
(7.5 times a year); and a relatively constant water level,
which sharply increases only during ﬂoods (in April–
May). The change in the water level is distinct only in
the upper segment; the ﬂood wave in the middle and,
especially, lower segments is manifested weakly. The
postﬂood decrease of water storage continues until
mid-June. To date, riverine conditions have been
retained only in the upper segment of the reservoir.
A decrease in the river ﬂow rate after the construc-
tion of the reservoir resulted in the silting of bottom
grounds (Filinova et al., 2002). Consequently, the num-
ber of rheophilic species in the zoobenthos decreased,
and they were replaced by pelophilic species, which
had been previously conﬁned to ﬂoodplain water bod-
ies (Belyavskaya et al., 1969; Konstantinov, 1969).
As the reservoir ﬂooded vast areas in the ﬂoodplains of
the Volga and its tributaries, the bottom fauna in the reg-
ulated river section became markedly enriched with
phytophilic invertebrates (Belyavskaya, 1965; Kon-
stantinov, 1969; Nechvalenko, 1976). Regular monitor-
ing studies of the bottom fauna in the channel part of
the reservoir provide evidence that rheophilic forms
have survived in a small area near the dam. The species
list of zoobenthos increased from 106 (Nechvalenko,
1980) to 185 entries (Filinova, 2003), with most of
newly recorded species occurring rarely or as single
individuals. In 2003 and 2004, species new for the res-
ervoir but typical for this region and previously classi-
ﬁed with larger species groups were included in this
list. These were
gr. A, and
(De Geer, 1776).
As most large lowland reservoirs, Volgograd Reser-
voir after ﬁlling was characterized by drastic ﬂuctua-
tions in the biomass of food zoobenthos, which were
explained by its consumption by benthophagous ﬁshes,
Bioinvasions in Macrozoobenthos of the Volgograd Reservoir
E. I. Filinova
, Yu. A. Malinina
, and G. V. Shlyakhtin
State Research Institute of Lake and River Fishery, Saratov Division, ul. Chernyshevskogo 152, Saratov, 410002 Russia
Saratov State University, ul. Astrakhanskaya 83, Saratov, 410026 Russia
Received August 24, 2006
—On the basis of long-term monitoring of macrozoobenthos in the Volgograd Reservoir, the causes
of changes in its species composition were analyzed and invading species were identiﬁed. During the ﬁrst 20–
25 years after construction of the reservoir, invading species appeared at a rate of 0.4 species per year. In the
subsequent years, this rate increased to one species per year due to spontaneous expansion of species and the
remote effect of their introduction.
: invading species, macrozoobenthos, Volgograd Reservoir, acclimation.