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Integrated assessment tools to gauge local functional status within freshwater ecosystems

Objective

Problems to be solved Biological monitoring of river ecosystems within Europe is based almost entirely on measures of community structure and ignores functional aspects of the systems being studied. However, rivers are managed in order to maintain essential 'ecosystem services', which are dependent on the functional integrity of the system. It is surprising, that complementary measures for assessing ecosystem function have yet to be developed. This project aims to redress the balance by developing an integrated set of tools that can be used to aid management-decision making by supplying information on the state of ecological processes that maintain key ecosystem services, and by providing a reference database that can be used to inform the setting of ecological quality targets. Scientific objectives and approach Tools development will reflect species functionally representative of the 3 ecoregions studied (in Portugal, The Netherlands and the UK). Two types of bioassay will be employed:
(i) measures of energy supply (i.e. primary production, detritus processing);
(ii) measures of energy consumption and transfer (i.e. algal (periphyton and phytoplankton) grazing and detritivore (shredder and collector) feeding). Methods will be adapted for in site deployment. Individual-based models (e.g. dynamic energy budget models) will be used to project the consequences of short-term changes in feeding rate measured in site bioassays for individual vital rates. Two types of model systems, representing high flow conditions, and low-flow conditions, will be used to validate in site tools. Two training courses will be organised, so that all partners can be instructed in the application of the developed tools. The tools will initially be tested in the absence of contaminants. Four reference compounds will be tested in each system using a regression design. Seasonal deployment of in site tests will be performed at least twice at selected sites to gain insight into temporal variability in response. Environmental information will be collected for each site. Data will be stored in a standard database format. Univariate and multivariate techniques will be used to characterise reference conditions for each tool and investigate relationships between site-specific environmental factors and response. A suite of in site tests will be deployed at each of a series of impacted sites, degraded by inputs from agricultural, mining, industrial and urban activities. A network of local steering groups will be established, consisting of water managers, from local, regional and/or national organisations; members will participate in the selection of sampling sites and will contribute to the project by supplying data (i.e. recent monitoring data) and expert knowledge on sampling sites. An interactive project internet site will be developed, with an open access area, to communicate project objectives and results to the public, and a restricted access area, password-protected front-end, to allow access to the database of information collected. At the end an Ecological Quality Manual, will be CD-ROM produced, to encourage the use of the bioassay techniques developed here. Expected impacts TARGET cuts across many inter-linked Community social objectives, from the preservation of environmental quality through protection of biodiversity and wildlife habitat and the sustainable and wise use of freshwater ecosystems, to the clear social and economic benefits, to the public and to the chemical industries involved, that may result from the use of functionally-based monitoring schemes. This will contribute to an overall improvement in the quality of life. The loss of biodiversity within Europe arises mainly from changes in traditional land use, habitat fragmentation by industrial infrastructure, urbanisation and exposure to mass tourism, misuse of chemical risk assessment programs and inappropriate monitoring tools. Since freshwater systems are currently managed in order to maintain essential "ecosystem services" that are dependent on the maintenance of functional integrity, monitoring tools are often based upon structural information alone. By explicitly linking the degree of impairment of an ecosystem to potential effects on the long-term sustainability of key ecosystem functions, sustainable use of freshwaters is appropriately addressed for the first time. Thus, the research output of TARGET will contribute to the preservation of environmental quality, enabling improved assessment of conservation requirements at local and national scale, meeting management needs and informing action from legislation at European scale to practical considerations at the stakeholder level.
Scientific achievements: Key processes influencing the economy and hence sustainability of running waters are detritus processing, detritivore feeding rates, algal production and grazer feeding rates. Thus in any assessment of the functioning of rivers, it is vital to incorporate these elements. TARGET focused on energy supply and transfer processes in running waters. During TARGET several techniques have been developed and/or refined, and SOPs (for both culture methods and in situ bioassays) were produced for: shredders -amphipods (Gammarus pulex, Echinogammarus. meridionalis and Atyaephyra desmaresti), cased-caddis (Sericostoma personatum, Calamoceras marsupus)-, column grazers (D. magna), collectors (Chironomus riparius), benthic grazers (Lymnaea peregra), primary production (immobilised algae), and detritus processing (leaf pack method). In situ bioassays were seasonally deployed at both reference and contaminated, across different ecoregions. Mathematical models were produced for species from four different functional levels: shredder (G. pulex), column grazer (D. magna), benthic grazer (L. peregra) and collector (C. riparius). These mathematical models are basic tools that share the same conceptual approach of internal resource partitioning.

Outputs from simulations allow the user to perform life table analysis for each species and infer the levels of functional impairment of an ecosystem. In addition to the bioassay data, characterization of all deployments, from reference and contaminated sites, included water chemistry, habitat and geographical information and invertebrate community structure. All this information was entered into the on-line database, developed by the project, and used later for numerical analysis. The database information was structured and organised as a set of relational databases. General location parameters including geographical characterization are grouped together. In all databases information can be selectively extracted and exported for further analysis and manipulation with appropriate statistical packages. Results indicate that the distribution of the bioassay values follows closely the distribution of the bmwp/aspt scores, that some sampling sites were erroneously classified as reference or impacted sites and, more importantly, that the use of some bioassays is potentially applicable to assess the ecological status of freshwaters (see also below).

In conclusion: Despite the existence of wide variability in response of the bioassays, results were consistent within deployments and across sites clear patterns of impairment of ecosystem function were observed. Some of the bioassays employed proved to discriminate between reference and contaminated sites, or even between different eco-regions, particularly the bioassays assessing the following functional groups: column grazer (i.e. Daphnia bioassays), shredder (i.e. amphipod bioassays) and, although less evident due to the fact that this type of bioassays was not used in all cases, to the benthic grazer (i.e. Chironomus bioassays). The gradient associated with the bioassays response follows the gradients of the BMWP/BMWP' and ASPT/ASPT' scores. Although requiring technical training bioassays do not require taxonomic expertise, such as the one required to use BMWP/BMWP' and ASPT/ASPT' scores. Moreover, bioassays can and should be conducted with native species maintained in the laboratory or collected from field sites known to be clean, thus increasing the ecological relevance of the bioassays. This is a major advantage for the potential future implementation of the developed tools to assess the ecological status of freshwaters.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UNIVERSITY OF COIMBRA
Address
Largo Marques De Pombal
3004-517 Coimbra
Portugal

Participants (3)

NETHERLANDS ORGANISATION FOR APPLIED SCIENTIFIC RESEARCH - TNO
Netherlands
Address
Laan Van Westenenk 501
7300 AH Apeldoorn
UNIVERSITY OF SHEFFIELD
United Kingdom
Address
Western Bank
S10 2TN Sheffield
UNIVERSITY OF STIRLING.
United Kingdom
Address

Stirling