Lupine Publishers- Environmental and Soil Science
Abstract
This study describes the species diversity, abundance and biomass of gastropods in the ecosystems of the southern part of
Western Siberia (Karasukskii district, Novosibirsk Oblast). Distribution and Quantitative Characteristics of Common Species of
Gastropoda are calculated. Twenty-one species of snails belonging to seven families were recorded, Lymnaeidae, Planorbidae,
Bulinidae, Physidae, Bithynhdae, Succineidae, and Zonitidae. The biodiversity of mollusks was studied using the Shannon- Weaver
index.
Introduction
The ecology of pond snails has been studied in the waterbodies
of the central part of European Russia [1], but the authors emphasize
the necessity of conducting similar studies in Siberia, and in other
regions of our country. Gastropoda are widely distributed in the
water bodies of the southern part of Western Siberia. They are
an important component of benthic communities and take part
in a number of trophic relationships. Some information about the
ecology of freshwater snails’ species is presented in the publications
[2-4] but many aspects are still poorly studied. In particular,
quantitative data on the communities of mollusks are scanty [5,6].
We, in a previous work [7] Jacquard index biodiversity gastropods
are calculated. The aim of the present investigation was to identify
the occurrence and distribution of freshwater snails in the lake,
rivers systems from the steppe zone the West Siberian Plain.
Materials and Methods
The species composition and biomass of snails in August of
2009 were studied (Novosibirsk Oblast, south of Western Siberia).
Samples were collected in different parts in the Karasuk River in
the upstream(near the villages of Bystrukha N 54026’ 53,2’’; E
800 55’ 50,5’ and Chernovka N 540 09’ 53,2’’; E. 800 02’ 54,2’) and
downstream near the villages of Gramotino and Sorochikha (N 500
45’ 19,4’’; E. 780 20’ 15,1’ and N 530 43’ 19,7’’; E 770 56’ 29,5’), and
in six lakes of the Karasuk system: Astrodym N 53036’ 59,4’’; E 770
48’ 04,7’, Krivoye (reaches: Blagodatnoye N 530 49’ 59,3’’; E. 780
03’ 17,3’’, Sopatoye N 530 48’ 28,7’’; E 78002’ 18,5’’ and Gusinoye
N 530 48’ 13,0’’; E 78004’ 00,8’’), Krotovo N 530 43’ 30’’; E 770 51’
31’’, Kusgan N 53044’ 23’’; E 770 53’25’’, Melkoye N 530 47’ 37,9’’; E
780 16’34,91’’, Titovo N 530 45’ 25,8’’; E 770 56’13,2’’.
The hydrological and hydrochemical characteristics of the
rivers and lakes in steppe zone in the West - Siberian Plain are
presented in the study by Savchenko (2010). The study was based
at the Karasuk Field Station (Institute of Systematics and Ecology
of Animals Russian Academy of Sciences; Karasukskii district,
Novosibirsk region). Mollusks were collected according to the
standard technique [8]. For a quantitative analysis of snails in the
lake-river systems they were collected by hand from sites of 0.25 m2
(50х50 cm). The control sites were in open parts and in macrophyte
stands at a depth of 0.1-1.1 m. To determine biomass, the collected
mollusks were dried on a filter paper for ≥1 min and weighed. The
species identification was made according to the shell and genital
system using the keys [9,10]. The ICA index (index of copulatory
apparatus) was one of the major criteria for the species definition
of mollusks. The species definition within the Lymnaeidae index for
mature specimens into account [6].
Results
Species Composition of Gastropods
In the Karasuk river - lakes system, of 21 species from 7
families of gastropods were recorded: Pond Snail - [Lymnaeidae];
Lymnaea (Radix) auricularia (L.,1758), L. (Peregriana) balthica (L.,
1758); L. (P.) fontinalis (Studer, 1820), L. (P.) ovata (Drap., 1805),
L. (P.) ampla (Hartmann, 1821), L. (P.) tumida (Held, 1836), and
Lymnaea (Stagnicola) saridalensis (Mozley, 1934) and Great Pond
Snails (Lymnaea) stagnalis (L., 1758), L. (L.) fragilis (L., 1758), L.
(L.) doriana (Bourguignat, 1862); Ramshorn snails, Planorbis
planorbis (L., 1758), Anisus vortex (L., 1758), A. contortus (L.,1758),
Segmentina nitida (Mull., 1774) [Planorbidae], and Planorbarius
corneus (L., 1758) [Bulinidae]; Physa fontinalis (L., 1758), Aplexa
nypnorum (L., 1758) [Physidae]; Bithynia tentaculata (L., 1758)
and B. troscheli (Paasch, 1842) [Bithyniidae]. Terrestrial gastropods
were defined by genus, Succinea sp. [Succineidae] and Zonitoides sp.
[Zonitidae].
Figure 1: Distribution (%) of gastropods in the Karasuk River and lakes of the Karasuk system
Table 1: Abundance and biomass of gastropods and the Shannon index in water objects from the Karasuk system.
Sixteen gastropod species were recorded in the river and 20 in
the lakes (Figure 1). Fifteen species were common for both the river
and the lakes. The snails L. (P.) ovata were found in the river only and
five species were found only in the lakes: (L. (L.) doriana and L. (P.)
ampla, only in the Astrodym lake; S. nitida only in the Krotovo lake;
A. nypnorum only in the Melkoye lake). Ramshorn snails P. corneus
were found in the Krivoye Krotovo and Titovo lakes. Gastropoda in
modern freshwater water bodies (the steppe zone West Siberian
Plain) are represented by Pulmonata and Prosobranchia species.
Both secondary aquatic pulmonate snails (four families) and
terrestrial species (two families) were recorded in the study area.
The terrestrial snails inhabit plants that grow close to the water’s
edge and appear in the samples of aquatic species. Prosobranchia
snails are primarily aquatic; they are the most ancient colonizers
of the continental water bodies and are represented by only one
family, Bithyniidae. Both bithyniid snails were recorded only in the
upper stream of the Karasuk River (close to Bystrukha Village) and
in Krotovo Lake [11].
Assessment of the Abundance and Biomass of Gastropods
The abundance of snails in the river varied from 10 up to
192 ind./m2 (Table 1). Lymnaeidae snails dominated, followed by
Bithyniidae snails were sub-dominants. The Shannon-Weaver
index, as calculated under the gastropod population density,
indicated an increase of the species diversity from 1.4-1.5 bit/ind.
(upper stream) up to 1.8-1.9 bit/ind. (lower stream). The maximum
abundance of snails in the lakes varied from 49 up to 400 ind./m2.
(Blagodatnoye reach and Melkoye). In lakes the Shannon-Weaver
index varied from 0.56 bit/ind. (Kusgan) up to 1.9 bit/ind. (Titovo;
Sopatoye reach). The maximum biomass of gastropods in the river
varied from 21.7 to 142.9 g/m2; or in lakes from 9.4 to 369.8 g/
m2 (Blagodatnoye reach and Melkoye). Lymnaeidae snail’s biomass
were dominated by, both in the river and in the lakes [12,13]. It
should be mentioned that high abundance did not always correlate
with high biomass. Thus, the high abundance (192 ind./m2) of
L. stagnalis corresponded to the biomass 1.26 g/ m2, which can
be explained by the prevalence of young snails in the samples.
Although an adult L. stagnalis can weigh 4.9 grams.
Twenty-one species of snails belonging to seven families
were recorded, Lymnaeidae, Planorbidae. Bulinidae, Physidae,
Bithynhdae, Succineidae, and Zonitidae. All the recorded mollusk
species are common in water bodies that are characterized by slow
cur rents, in stagnant (mostly perennial) and semilotic water pools;
they are common species in the southern part of Western Siberia.
Lymnaeidae snail’s biomass were dominated by, both in the river
and in the lakes.
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