Integrated Assessment of the Ecological Status of Bulgarian Lowland and Semi-Mountain Natural Lakes

Detelina Belkinova,Emilia Varadinova,Svetoslav Cheshmedjiev,Lilyana Yurukova,Gana Gecheva

doi:10.4236/jep.2013.46a004

Detelina Belkinova, Emilia Varadinova + Show 3 more

Open Access

https://doi.org/10.4236/jep.2013.46a004

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Abstract

This work focuses on an integrated approach for lake ecological status assessment, elaborated according to the requirements of the European Water Framework Directive (WFD). Data from five lowland and semi-mountain lakes in Bulgaria (Southeast Europe) collected from two years (2011-2012) form the basis for an integrated assessment and the definition of reference conditions. Several metrics were applied in combination, to classify lakes into five ecological status classes. Assemblages of aquatic organisms: phytoplankton, macrophytes and benthic macroinvertebrates, together with 11 supporting physico-chemical parameters were studied. The assessed unique conditions suggested that reference conditions of Bulgarian lakes have natural variability. This first baseline study illustrated specific cases within the lake types that should be assessed in details before providing standardized classification systems in compliance with the requirements of WFD.

Highlights

As a result of human activities, natural lakes have been rapidly diminishing in Bulgaria, while man-made water bodies have emerged
This work focuses on an integrated approach for lake ecological status assessment, elaborated according to the requirements of the European Water Framework Directive (WFD)
The assessed unique conditions suggested that reference conditions of Bulgarian lakes have natural variability

Summary

Introduction

As a result of human activities, natural lakes have been rapidly diminishing in Bulgaria, while man-made water bodies have emerged. Bulgaria is relatively poor in natural lakes: about 250 water bodies of surface area 9500 ha (only 0.09% of the Bulgarian territory), mostly glacial, coastal and lowland [1]. Our research followed the concept that reference conditions are a representation of biological integrity, which can be defined as the ability to support and maintain a balanced, integrated, adaptive community of organisms having a species composition, diversity and functional organization comparable to that of the natural habitat of the region [2]. Most biological assessment systems are based on the concept of comparing the current biological community to the “reference conditions”—biological conditions associated with no or very low human pressure

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