Macroinvertebrates of the Natural Substrate of the Sava River – Preliminary Results

Momir Paunović1, Jelena Tomović1, Simona Kovačević2, Katarina Zorić1, Krešimir Žganec3, Vladica Simić2, Ana Atanacković1, Vanja Marković1, Margareta Kračun1, Sandra Hudina3, Jasna Lajtner3, Sanja Gottstein3 and Andreja Lucić3

 


1 University of Belgrade, Institute for Biological Research “Sinisa Stankovic”, 142 Despota Stefana Boulevard, Belgrade, Serbia, E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

2 University of Kragujevac, Faculty of Science, Institute for Biology and Ecology, Radoja Domanovića 12, Kragujevac, Serbia

3 University of Zagreb, Faculty of Scence, Division of Biology, Rooseveltov trg 6, Zagreb, Croatia

 

Abstract

The objective of this study is to present the comparable data on macroinvertebrate communities from the natural bottom substrate along the middle and lower stretch of the Sava River. The study was carried out in September 2011 at eight sites of the sector between Zagreb - Martinska Ves and Belgrade – at the confluence into the Danube. The data presented could be used as baseline information for any future management of the main course of the Sava River.

Keywords: Aquatic macroinvertebrates, Sava River, community structure, species richness

 

 

Introduction

The Sava River is the second largest tributary of the Danube. The river basin is shared by four countries: Slovenia, Croatia, Bosnia and Herzegovina and Serbia. Despite its importance as a large transboundary river, macroinvertebrate communities of its main course have not been systematically studied recently. Up until this study, the most detailed research of macroinvertebrates of the Sava River was performed by Matoničkin et al. (1975). Since then, the macroinvertebrate community has been studied within limited stretches (e.g. in the Belgrade region). Published results concerning macroinvertebrates of the Sava River were related mostly to restricted stretches, annual investigation (Jakovcev 1988, 1989, 1991; Martinovic-Vitanovic et al., 1999; Paunovic, 2004; Paunovic et al., 2008) or specific research topics (e.g. non-indigenous taxa), thus offering limited data.

The aim of this paper is to present the preliminary results of investigating the macroinvertebrate community of the natural substrate along the middle and lower reach of the Sava River, in the sector between Zagreb (Martinska Ves) and Belgrade (confluence into the Danube). Existing data on macroinvertebrate fauna of the Sava River are lacking and insufficient to be effectively used for water management purposes, such as sectioning of the river (typology), water body delineation, defining ecological status class boundaries, design of water status screening system, harmonization of ecological status assessment methods between the Sava countries, as well as improvement of large river sampling methodologies.

The above mentioned activities are related to the implementation of the EU Water Framework Directive (WFD, 2000). Thus, this work offers a basis of comparable data for further consideration along a considerable stretch of this large river.

 

Study Area

The Sava River Basin (SRB) covers an area of 95,719 km2 and is situated in the southern part of the Danube Basin (Figure 1). Together with its tributaries, this 940 km long watercourse represents a mighty river system. The Sava begins in mountains of Slovenia and flows throughout the lowlands of Croatia, Bosnia and Herzegovina, and Serbia, and confluences the Danube in Belgrade (river km 1171). According to average discharge (1,513 m3/s at station Sremska Mitrovica, about 100 km from the confluence to the Danube – SRBA 2009), it is the largest tributary of the Danube. Further, by its catchment area, the Sava is the second largest sub-basin of the Danube after the Tisa River Basin. The Sava River Basin is shared by Bosnia and Herzegovina (40.0 % of the basin area), Croatia (26.0 %), Serbia (15.4 %), Slovenia (11.0 %), Montenegro (7.5 %), and Albania (0.1 %). About 8.8 million people live in the basin (Sava RBMP, 2011). More than 50 % of the Sava watercourse is navigable, from the mouth up to the Kupa confluence.

1
Figure 1: Sampling sites along the investigated stretch

 

The elevation of the Sava River Basin with a mean of 545 m a.s.l. ranges between 71 m.a.m.s.l. at the mouth of the Sava River in Belgrade (Serbia) and 2,864 m.a.m.s.l. (Triglav, Julian Alps in Slovenia).

The Sava River Basin is heterogeneous concerning overall environmental conditions. Due to its geographic position, diverse climate, petrographic and pedological variety, and orographic characteristics, it is one of the most complex regions in Europe concerning the distribution of plants and animals (Lopatin and Matvejev, 1995).

According to the register of areas important for biodiversity conservation, 165 sites along the Sava River were identified with total surface area of more than 18,226 km2 (Sava RBMP, 2011). In lowland areas, agricultural activities and urban wastewater (nutrient and organic pollution) may contribute to the degradation of protected areas (PA).

Pesticides and overuse of fertilizers in regions with intensive agriculture contributes to water pollution. Groundwater depletion, mostly due to the exploitation of river bed material (sand and gravel extraction), as well as changes in the water regime (e.g. flood control prevention of periodical flooding as a consequence of embankment and damming) the structure and functioning of floodplain wetlands depend on, can threaten water dependent PAs, especially lowland forests.

 

Material and methods

Macroinvertebrates sampling was performed during September 2011 at eight sampling sites on the stretch between 622 km and 17 km along the Sava River (Figure 1, Table 1).

 

tab1
Table 1: Sampling sites along the investigated stretch

 

Quantitative samples (n=10) were collected using hand nets (mesh size 500 μm) on the area of 0.0625 m2, in a shallow bank region (up to the depth of 1.5 m). Substrate at the sampling site has not been changed by any form of channelization and thus corresponds to natural substrata along the assessed river reach. Samples were collected from all available types of substrate (mainly gravel, sand and mud), taking into consideration the relative contribution to each microhabitat and the number of samples collected from particular microhabitats within each reach corresponds to the relative contribution of this microhabitat to the substrate of assessed river reach (10% = 1 sample). Approximate length of assessed reach at each sampling site was 100 m of the shore region.

Asterics software Version 3.3.1. (AQEM, 2002) was applied for calculating classes of the species in regard to saprobic preference, current, substrate type, river zonation and feeding type composition while the autecological data are used from AQEM (2002).

To present the spatial distribution of the macroinvertebrate community, correspondence analysis (Pielou, 1984) was applied. "Statistica for Windows 5.1 (Edition '97)" was used for statistical processing of the data.