Assessment of environmental management effects in a shallow water basin using mass-balance models
Brando, V.E.; Ceccarelli, R.; Libralato, S.; Ravagnan, G. (2004). Assessment of environmental management effects in a shallow water basin using mass-balance models. Ecol. Model. 172(2-4): 213-232 In: Ecological Modelling. Elsevier: Amsterdam; Lausanne; New York; Oxford; Shannon; Tokyo. ISSN 0304-3800; e-ISSN 1872-7026, more Also appears in:Christensen, V.; Maclean, J.L. (Ed.) (2004). Placing fisheries in their ecosystem context. Ecological Modelling, 172(2-4). Elsevier: Amsterdam. 103-440 pp., more |   |
| Keywords | Eutrophication
Trophic relationships
Marine/Coastal |
| Authors | | Top | - Brando, V.E.
- Ceccarelli, R.
- Libralato, S.
- Ravagnan, G.
| | |
| Abstract | Comparative analysis of trophic networks was carried out to evaluate environmental management actions aimed at counteringan environmental crisis in Orbetello Lagoon, Italy. Two mass-balance models of this shallow water coastal systemwere constructed, for 1995 and 1996. During this period, there was an observed change in the composition of the submergedvegetation that indicated a significant improvement in the lagoon’s ecology. Mass-balance models were built usingthe Ecopath modelling software in order to explain the energy transfer through the trophic levels (TLs) of the lagoon’s ecosystem.Comparative analysis of the two trophic networks allowed a complete description of the lagoon, and gave clear indicationsregarding the ‘eutrophication level’ sensu Nixon and the stage of system maturity sensu Odum of the ecosystem for the 2 years.The turnover rate (production/biomass ratio) of pleustophytes was proposed as an indicator of “environmental health” at theecosystem level because it allows positioning the submerged vegetation as a whole along an axis of adaptation strategies tonatural selection. All the indices of ecosystem maturity and stability examined showed that the lagoon was in a more stablecondition in 1996 than in 1995, although the system was still in a condition of stress.The effects of management actions carried out in the system were quantified by estimating the changes in primary productionand accumulation of detritus in the system. Management of the lagoon as an extensive aquaculture operation was assessed byanalysing the fishery catch, the transfer efficiencies at different trophic levels and the impact of cormorants, and it was found tocontribute to system stability. |
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