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2M - Monitoring of function and structure (WEP/155) Can we assess ecosystem function using the relationship between in situ bioassays and DMB models? Nogueira, António1, Baird, Donald2, Jak, Robbert3, Maltby, Lorraine4, Soares, Amadeu1, 1 Universidade de Aveiro, Aveiro, Costa de Prata, Portugal2 University of Stirling, Stirling, Scotland, UK3 TNO, Den Helder, North Holland, The Netherlands4 University of Sheffield, Sheffield, England, UK ABSTRACT- Toxic substances inhibit feeding, resulting in reduced fecundity and survival, thus compromising individual fitness in resident populations, which may ultimately lead to local extinctions. This causality chain can be used to interpret measurements made using in situ bioassays, over short time periods in terms of the risk to populations. Where those populations play an important role as dominant or keystone species within ecosystems, the bioassays may give an indication of potential impairment of ecosystem function. For example, toxic effects on shredding invertebrates can reduce rates of detritus processing. These effects also propagate through the food web by interfering with the availability of resources for other consumer organisms. Dynamic mass Budget (DMB) models can be used to link short-term observations (e.g. feeding) & long-term responses (e.g. reproductive success) of individuals. Outputs from DMB models can be used as inputs to population models, to predict population impacts. Thus linking field bioassays with DMB models can be used to evaluate the functional impairment of the ecosystem. A set of DMB models representing three trophic categories of river invertebrates (shredders, collectors, and filter feeders) will be presented and the implications of localised impairment discussed in relation to ecosystem functioning and its importance within the European Water Framework Directive. Key words: functional assessment, rivers, in situ bioassays, DMB models |
