Water Framework Directive Intercalibration Technical Report: Lake phytobenthos ecological assessment methods

The European Water Framework Directive (WFD) requires the national classifications of good ecological status to be harmonised through an intercalibration exercise. In this exercise, significant differences in status classification among Member States are harmonized by comparing and, if necessary, adjusting the good status boundaries of the national assessment methods. Intercalibration is performed for rivers, lakes, coastal and transitional waters, focusing on selected types of water bodies (intercalibration types), anthropogenic pressures and Biological Quality Elements. Intercalibration exercises were carried out in Geographical Intercalibration Groups - larger geographical units including Member States with similar water body types - and followed the procedure described in the WFD Common Implementation Strategy Guidance document on the intercalibration process (European Commission, 2011). In a first phase, the intercalibration exercise started in 2003 and extended until 2008. The results from this exercise were agreed on by Member States and then published in a Commission Decision, consequently becoming legally binding (EC, 2008). A second intercalibration phase extended from 2009 to 2012, and the results from this exercise were agreed on by Member States and laid down in a new Commission Decision (EC, 2013) repealing the previous decision. Member States should apply the results of the intercalibration exercise to their national classification systems in order to set the boundaries between high and good status and between good and moderate status for all their national types. Annex 1 to this Decision sets out the results of the intercalibration exercise for which intercalibration is successfully achieved, within the limits of what is technically feasible at this point in time. The Technical report on the Water Framework Directive intercalibration describes in detail how the intercalibration exercise has been carried out for the water categories and biological quality elements included in that Annex. The Technical report is organized in volumes according to the water category (rivers, lakes, coastal and transitional waters), Biological Quality Element and Geographical Intercalibration group. This volume addresses the intercalibration of the cross-GIG phytobenthos ecological assessment methods

The Cascading Reservoir Continuum Concept (CRCC) and its application to the river Tietê-basin, São Paulo State, Brazil

Major changes in the water quality and basic features of phytoplankton assemblages in a series (cascade) of 7 reservoirs int he middle Tiete river, south-east Brazil were investigated in February 1998 (rainy season). The biologically non-affected variables change rapidly in the upstream reservoirs and then remain constant while biologically affected ones showed a prolonged response that can be explained only if considering the cascade as an entire system. The changes in the first reservoir in the system accord to the predictions of the serial discontinuity concept (SDC): the river continuum (RCC) is basically affected. However, changes on the downstream reservoirs become continuous again and show that the same processes remain operative throughout the entire river continuum. Therefore, a cascading reservoir continuum concept (CRCC) can be proposed for handling the ecological processes at a system level. A comparison of the present data with those recorded previously for some of the reservoirs show a fast growing eutrophication of the upper reservoirs in the cascade. On the basis of the CRCC and the present ecological status and water quality of the Tiete cascade a progressive downstream eutrophication can be forecasted thus calling attention for urgent need of restoration measures at the headwaters

Relationship between gill raker morphology and feeding habits of hybrid bigheaded carps (Hypophthalmichthys spp.)

Bigheaded carps and especially silver carp have been considered as an effective biological control for algal blooms, thus were introduced to several countries in the last decades, including Hungary. Our aim was to explore the feeding habits of bigheaded carps in Lake Balaton (Hungary), where the stock consists mainly of hybrids (silver carp × bighead carp). We examined the relationship between filtering apparatus (gill raker) morphology and size-distribution of planktonic organisms in the food. We failed to find any significant relationship between gill raker parameters and plankton composition in the filtered material. Bigheaded carps with various types of gill rakers consumed food within the same size-spectrum, independently of the rate of hybridization. However, the linkage between the proportion of different planktonic size classes in the water and in the diet of fish was detectable in case of both phytoplankton and zooplankton consumption, suggesting that the seasonally variable availability of different food items was an important factor in determining the food composition of bigheaded carps. We can deduce that bigheaded carps consume high amounts of zooplankton to meet their energy requirements, and the diet overlap among bigheaded carps and other planktivores may exert negative effects on native fish populations

Resisting annihilation: relationships between functional trait dissimilarity, assemblage competitive power and allelopathy

Abstract Allelopathic species can alter biodiversity. Using simulated assemblages that are characterised by neutrality, lumpy coexistence and intransitivity, we explore relationships between within-assemblage competitive dissimilarities and resistance to allelopathic species. An emergent behaviour from our models is that assemblages are more resistant to allelopathy when members strongly compete exploitatively (high competitive power). We found that neutral assemblages were the most vulnerable to allelopathic species, followed by lumpy and then by intransitive assemblages. We find support for our modeling in real-world time-series data from eight lakes of varied morphometry and trophic state. Our analysis of this data shows that a lake's history of allelopathic phytoplankton species biovolume density and dominance is related to the number of species clusters occurring in the plankton assemblages of those lakes, an emergent trend similar to that of our modeling. We suggest that an assemblage's competitive power determines its allelopathy resistance

Floodplain management in temperate regions : is multifunctionality enhancing biodiversity?

Background: Floodplains are among the most diverse, dynamic, productive and populated but also the most threatened ecosystems on Earth. Threats are mainly related to human activities that alter the landscape and disrupt fluvial processes to obtain benefits related to multiple ecosystem services (ESS). Floodplain management therefore requires close coordination among interest groups with competing claims and poses multi-dimensional challenges to policy-makers and project managers. The European Commission proposed in its recent Biodiversity Strategy to maintain and enhance European ecosystems and their services by establishing green infrastructure (GI). GI is assumed to provide multiple ecosystem functions and services including the conservation of biodiversity in the same spatial area. However, evidence for biodiversity benefits of multifunctional floodplain management is scattered and has not been synthesised. Methods/design: This protocol specifies the methods for conducting a systematic review to answer the following policy-relevant questions: a) what is the impact of floodplain management measures on biodiversity; b) how does the impact vary according to the level of multifunctionality of the measures; c) is there a difference in the biodiversity impact of floodplain management across taxa; d) what is the effect of the time since implementation on the impact of the most important measures; and e) are there any other factors that significantly modify the biodiversity impact of floodplain management measures? Within this systematic review we will assess multifunctionality in terms of ESS that are affected by an implemented intervention. Biodiversity indicators included in this systematic review will be related to the diversity, richness and abundance of species, other taxa or functional groups. We will consider if organisms are typical for and native to natural floodplain ecosystems. Specific inclusion criteria have been developed and the wide range of quality of primary literature will be evaluated with a tailor-made system for assessing susceptibility to bias and the reliability of the studies. The review is intended to bridge the science-policy interface and will provide a useful synthesis of knowledge for decision-makers at all governance levels

Strength and uncertainty of phytoplankton metrics for assessing eutrophication impacts in lakes

Phytoplankton constitutes a diverse array of short-lived organisms which derive their nutrients from the water column of lakes. These features make this community the most direct and earliest indicator of the impacts of changing nutrient conditions on lake ecosystems. It also makes them particularly suitable for measuring the success of restoration measures following reductions in nutrient loads. This paper integrates a large volume of work on a number of measures, or metrics, developed for using phytoplankton to assess the ecological status of European lakes, as required for the Water Framework Directive. It assesses the indicator strength of these metrics, specifically in relation to representing the impacts of eutrophication. It also examines how these measures vary naturally at different locations within a lake, as well as between lakes, and how much variability is associated with different replicate samples, different months within a year and between years. On the basis of this analysis, three of the strongest metrics (chlorophyll-a, phytoplankton trophic index (PTI), and cyanobacterial biovolume) are recommended for use as robust measures for assessing the ecological quality of lakes in relation to nutrient-enrichment pressures and a minimum recommended sampling frequency is provided for these three metrics