Multi-habitat sampling method for benthic macroinvertebrate communities in different river types in Bulgaria

 Svetoslav Cheshmedjiev1, Rabia Soufi2, Yanka Vidinova3, Violeta Tyufekchieva4, Ivanka Yaneva5, Yordan Uzunov6, Emilia Varadinova7

1 SI Eco Consult Ltd.; Postal address: 64 Ralevitza St., entr. III (B), app. 49, 1320 Sofia, Bulgaria; Telephone: +359 887 922 586; Fax number: +359 2 9548783; E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

2 Institute for Biodiversity and Ecosystem Research (at the Bulgarian Academy of Sciences), Telephone: +359 889607577, E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

3 Institute for Biodiversity and Ecosystem Research (at the Bulgarian Academy of Sciences), Telephone: +359 887603814, E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

4 Institute for Biodiversity and Ecosystem Research (at the Bulgarian Academy of Sciences), Telephone: +359 2 71 87 67, E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

5 University of Sofia, Faculty of Biology, Telephone: +359 889198849, E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

6 Institute for Biodiversity and Ecosystem Research (uat the Bulgarian Academy of Sciences), E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

7 Institute for Biodiversity and Ecosystem Research (at the Bulgarian Academy of Sciences), E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

 

Abstract

 

The multi-habitat sampling method (adapted version), combining the techniques according to the AQEM/STAR methodology, EN 27828:1994, EN ISO 5667-1:2006/AC: 2007, EN ISO 5667-3:2003/AC: 2007, EN 28265:1994, was developed in compliance with type-specific river conditions in Bulgaria. A number of specifics with the original sampling method were defined. Ten replicas are sampled per monitoring site with sizes 25 х 25 cm or larger 30 х 30 cm. These replicas (sampling frames) should be allocated according to the percentage ratio of the main bottom substrata. The operator should place the sampling net on the bottom, against the velocity, covering a slightly larger area than the projection of the handnet frame (e.g. from 25 cm x 25 cm to reach 30 cm x 30 cm) to carry out wash sampling (stones, gravel, macrophytes) or kick sampling (stones, pebbles, gravel, sand, silt, etc.). In the beginning, a balance between the number of frames for kick-sampling and wash-sampling should be made. Usually the ratio is 50:50 between kick-sampling and wash-sampling for mountain and semi-mountain river types, but the ratio could depend on the operator judgement. When washing macrophytes, the macrophyte types, e.g. emergent/submerged/helophytes have to be recorded. Finally the macroinvertebrate results are calculated as number/m2. A multi-layer concept is developed to translate macroinvertebrate abundance data from "3-D" large water macrophytes (relative macrophyte biovolume or m3) to area in m2.

 

Keywords: multi-habitat sampling, benthic macroinvertebrates, river types, Water Framework Directive

 

 

 

Introduction

The European Water Framework Directive (WFD) 2000/60/ЕС requires mandatory monitoring of the benthic macroinvertebrate communities (macrozoobenthos) and the ecological status/potential assessment of rivers. Most of the Geographic Intercalibration Groups (GIG) under the WFD compare macroinvertebrate data sets using as a measurement the number of individual macroinvertebrates per square meter, based on the so-called multi-habitat sampling.

Within the national river monitoring system in Bulgaria, the international sampling standard EN 27828:1994 is used for a 5 minute sampling time, which correlates with multi-habitat methods based on the sampling area approach.

Development of coherent sampling techniques to assess the benthic macroinvertebrates in rivers according to the requirements of the Water Framework Directive 2000/60/EC is a crucial challenge for each European country, particularly concerning local type-specific river conditions. However, counting all the invertebrates from numerous replicas in the multi-habitat samples that are usually collected for ecological status assessment is time-consuming and costly. In order to standardize biological assessment of surface waters in Europe, a standardized multi-habitat method for sampling, sorting and identification of benthic macroinvertebrates in running water was developed during the AQEM project (2002). The AQEM method has proven to be relatively time-consuming. Hence, this study explored the consequences of a reduction in sample size on efforts/costs and bioassessment results.

A multi-habitat sampling method (adapted version), combining techniques of the AQEM/STAR methodology as well as the following EN and ISO standards: EN 27828:1994, EN ISO 5667-1:2006/AC: 2007, EN ISO 5667-3:2003/AC: 2007, EN 28265:1994, has been developed in compliance with type-specific river conditions in Bulgaria (Cheshmedjiev et al. 2010a, 2010b). In the process of research, certain specifics of the sampling method have been defined which should be distinguished by the original methods (AQEM 2002; Barbour at al., 1999).




Material and methods

 

Sampling techniques based on both EN 27828:1994 for a time of 5 minutes (kick – and wash-sampling) and the multi-habitatmultihabitat approach (AQEM/STAR methodology) have been compared taking into consideration existing micro-habitats (bottom substrata) in rivers,river, i.e. megalithal (stones > 40 cm), mesolithal (cobbles 6-20 cm), microlithal (gravel 2-6 cm), akal (2 mm – 2 cm), psammal (sand), psammopelal (sand and clay), agrilal (silt, mud), xylal (wooden debris), etc. Eight mineral micro-habitats and ten biotic micro-habitats werehave been involved in the sampling method. In case of implementing the multi-habitatmultihabitat sampling method, the number of sub-samples (replicas) conforms to the percentage ratio of the bottom habitats, and a final composite sample representingrepresented for the monitoring site is prepared.

 

 

Fifteen representative monitoring sites from two ecoregions (ecoregion 7 Eastern Balkans Balkan and ecoregion 12 Pontic Province) having long historic data series from both types of sampling (for time series or per sq. meter), were selected. In 2009 a comparative analysis washas been carried out to assess the correlation between the nationally adopted for macroinvertebrate sampling used on a national level in accordance with EN 27828:1994 (sampling for time series),) and the multi-habitatmultihabitat method (per sq. meter), which is an adapted version of the AQEM/STAR methodology. Based on sound pragmatic principles, the original European multi-habitatmultihabitat method has been adapted to type-specific river conditions of the ecoregion 7 Eastern Balkans Balkan and ecoregion 12 Pontic Province.

 

 

 

Picture 1: Handnet kick sampling and quantitative sampling of river macroinvertebrate communities (S. Cheshmedjiev, 2009)

Picture 1: Handnet kick sampling and quantitative sampling of river macroinvertebrate communities (S. Cheshmedjiev, 2009)