Vasiliki Tsiaoussi

• Head of Department at Greek Biotope/Wetland Centre

This report provides a guide for assessing the hydromorphological quality of natural and artificial lake water bodies in accordance with the requirement of the Water Framework Directive (WFD). First, 60 metrics are described for characterizing the mandatory lake hydromorphological quality elements comprising those that are hydrological (i.e., quan...

This study investigates the performance of published bio-optical remote sensing indices/algorithms for monitoring water quality changes in Lake Karla, Greece, caused by Storm Daniel after the September 2023 flooding event. Commonly applied indices were utilised to estimate chlorophyll-a (Chl-a) and total suspended solids (TSS) using Sentinel-2 high...

Aquatic vegetation is an essential component of lake ecosystems, used as a biological indicator for in situ monitoring within the Water Framework Directive. We developed a hierarchical object-based image classification model with multi-seasonal Sentinel-2 imagery and suitable spectral indices in order to map the aquatic vegetation in a Mediterranea...

The objective of this study was to investigate the effects of substrate type in macroinvertebrate assemblages in Mediterranean lakes. Samplings have taken place in the littoral zone of 21 lakes in Greece, between 2015 and 2018. We compared benthic macroinvertebrate assemblages among three substrate types of their littoral zones; sandy, covered with...

Mediterranean lakes present particular challenges when developing ecological assessment techniques, due partly to long histories of human activity in their catchments but also to strong interactions with climate, intensifying in recent decades due to global warming. A survey of diatoms in lakes in Greece revealed both a strong nutrient gradient and...

This study provides an annotated checklist of the freshwater fish species recorded in lentic ecosystems of Greece. Species distributional data were derived from an extensive review of published and unpublished sources and were evaluated for their consistency, adequacy and reliability. Overall, 650 freshwater lentic ecosystems (149 natural and 501 a...

A new multimetric index (HeLLBI) based on littoral benthic macroinvertebrates is presented in this paper for classification of Greek natural lakes, in compliance with the requirements of Water Framework Directive (WFD). The method was developed based on the collection of littoral benthic invertebrate fauna and environmental data from 109 sampling s...

The EU Water Framework Directive foresees the ecological assessment of surface waters against identified pressures. Nutrient loading is the main pressure impairing the ecological quality of lake ecosystems, and aquatic macrophytes are considered good indicators of ecological response. In this study, we statistically assessed different aspects of aq...

The “One Out–All Out” (OOAO) principle imposed by the WFD selects the worst ecological status assessed by different biological quality elements (BQEs). Since it is a precautionary rule that can lead to problems of underestimation of the overall status, its amendment has been a matter of debate for WFD 20⁺. The use of fuzzy methods that express the...

Cyanotoxins (CTs) produced by cyanobacteria in surface freshwater are a major threat for public health and aquatic ecosystems. Cyanobacteria can also produce a wide variety of other understudied bioactive metabolites such as oligopeptides microginins (MGs), aeruginosins (AERs), aeruginosamides (AEGs) and anabaenopeptins (APs). This study reports on...

Eutrophication caused by nutrient enrichment is a predominant stressor leading to lake degradation and, thus, the set-up of boundaries that support good ecological status, the Water Framework Directive’s main target, is a necessity. Greece is one of the Member States that have recorded delays in complying with the coherent management goals of Europ...

Transitional ecosystems along the Aegean coastline are formed at the interface between land and sea, connecting the terrestrial and marine environment. They are grouped in four major types: coastal marshes, coastal lagoons, river mouths/estuaries, and river deltas. Along the Aegean coastline, in continental Greece, we identified and mapped 254 larg...

Aims : This study aims to contribute to the knowledge of European freshwater lake ecosystems with updated and new information on aquatic plant communities, by conducting national-scale phytosociological research of freshwater lake vegetation in Greece. Moreover, it investigates the relationship between aquatic plant communities and lake environment...

Aims: This study aims to contribute to the knowledge of European freshwater lake ecosystems with updated and new information on aquatic plant communities, by conducting national-scale phytosociological research of freshwater lake vegetation in Greece. Moreover, it investigates the relationship between aquatic plant communities and lake environmenta...

The objective of this project is to provide comprehensive monitoring of hydrological, chemical and hydrobiological characteristics of the water bodies in the Ohrid Lake watershed, and input for better understanding of the ecological status of the water bodies and the hydrological regimes, in line with the requirements of the EU Water Framework Dire...

Modern water resource management requires biomonitoring of the structure and functioning of freshwater ecosystems, which may be better illuminated by functional trait distribution patterns and responses across human-induced pressure gradients. In this study, we applied the RLQ, the fourth-corner and their novel combination methods, in order to asse...

The national monitoring network of waters in Greece, in the context of Water Framework Directive (WFD), comprises 50 lake water bodies, both natural and artificial. The aims of the study are: (i) to present the pressures resulting from land cover and population density at river basin level; and (ii) to link catchment area features with physicochemi...

The Water Framework Directive (WFD) requires Member States to develop appropriate assessment methods for the classification of the ecological status of their surface waters. Mediterranean region has lagged behind in this task, so we propose here the first developed method for Greek lakes, Hellenic Lake Macrophyte (HeLM) assessment method. This meth...

Presentation on the sampling methodology for monitoring lake macrophytes

First effort for evaluation assessment of four Greek lakes, using data from monitoring macrophytes

Forests are expected to be affected by climate change; consequently, adaptation of forest management to climate change is considered necessary in order to enable the conservation of healthy, productive forests. In the framework of the EU LIFE+ AdaptFor project (www.life-adaptfor.gr), an effort was made to assess vulnerability of four selected Greek...

We develop a conceptual framework for determining insurance values associated with a gene bank and we apply the methodology to the Greek Gene Bank (GGB), the largest ex situ conservation program in Greece. To evaluate the insurance value generated by the holdings of the GGB genetic resources, the current study examined scenarios for alternative arr...

One of the key actions identified by the Water Framework Directive (WFD; 2000/60/EC) is to develop ecological assessment tools and carry out a European intercalibration (IC) exercise. The aim of the Intercalibration is to ensure that the values assigned by each Member State to the good ecological class boundaries are consistent with the Directive’s...

Greece, as part of the Mediterranean Basin, is projected to be among the most vulnerable countries to climate change. It is therefore quite urgent to adapt forest management to the changing climate in order to enhance biodiversity and to enable the conservation of healthy and productive forests. In the framework of the project LIFE+ AdaptFor (www.l...

Human-induced pressures are known to be one of the main causes of biodiversity loss. In order to readily assess policy impacts on biodiversity, a cost-effective evaluation tool is developed, using species sensitivity scores. We demonstrate the potential effects of a selected policy option, being woody bioenergy crop production, on a wide range of s...

ΤΥΠΟ-ΧΑΡΑΚΤΗΡΙΣΤΙΚΕΣ ΣΥΝΘΗΚΕΣ ΑΝΑΦΟΡΑΣ: Περιγραφή των βιολογικών στοιχείων ποιότητας (σύµφωνα µε την ορολογία της Οδηγίας 2000/60/ΕΕ), όπως απαντούν στους τύπους υδατικών σωµάτων της Ελλάδας σε φυσικές συνθήκες (αδιατάρακτες από τον άνθρωπο). Ανάπτυξη δικτύου και παρακολούθηση των εσωτερικών, µεταβατικών και παράκτιων υδάτων της χώρας-αξιολόγηση /...