Resumen de Avaluació dels efectes del canvi global sobre la qualitat ecològica de l'aigua de les conques fluvials mediterrànies
Mediterranean river basins are exposed to a great water demand to meet the needs of the increasing population and other anthropogenic activities related such as the development of industry, intensive agriculture and tourism activities. In addition, these areas have strong inter-annual climatic variability mainly characterized by a dry period in summers, which represents an evident variability in rivers discharge annual regime, from permanent to temporal and a variation in the water quality status.
From this Global Change context, springs up the need to build new indicators to evaluate the impacts of Global Change in two Mediterranean river basins such as Tordera and Besòs river basins (North-East Iberian Peninsula). These two river basins are contiguous but have different hydrological regimes and population sizes, so pressures and impacts are diverse and are considered as two study cases which contributes to increase transferability to other Mediterranean river basins.
For that purpose, three main scopes are analysed three main scopes: the ecological through the evolution of the ecological quality status in both study areas; the anthropogenic, assessing the influence of wastewater treatment plants effluents on the ecological status and exploring the main Global Change effects through Land Use Land Cover (LULC) changes; and the social, exploring relationships between local perceptions and ecological quality status.
A model is run for developing the new approach, correlating water quality indicators stablished by the Water Framework Directive (2000/60/EC) such as biological indicators (macroinvertebrates, riparian vegetation and diatoms), physicochemical indicators (ammonium, nitrates, nitrites, phosphates and conductivity) to assess the ecological status of the water systems with the Land Use and Land Cover Changes Analysis (forest grassland and shrubs, urban, bare forested soil, crops and continental waters areas). In addition, climatic and topographic variables such as the slope, the altitude and the Water Availability Index (WAI) were added to this model as important explanatory variables to the variation of the water quality indicators.
The results show that this new and comprehensive assessment has the potential to assess the Global Change effects in a Mediterranean context. This tool could be profitable to provide a wider vision of a studied area and to detect the locations to focus future management plans and measures.
