National

The project focus on the evolution of soil and vegetation in two mediterranean salt marshes of SE of Spain. In previous studies (1991-1993) we identified plant zonation and edaphic gradients in these salt marhes. Now, the objectives are as follow: 1.- to identify the evolution of soils (salinity, water regime and nutrients) and vegetation (cover and species diversity) in the last 10 years, and to relate these changes with human activities (agriculture practices and others) in nearby areas.

The presence of mining wastes in semiarid areas of Southeast Spain is considered an important environmental concern due to the risk of metal transfer to the biota and human population. The revegetation or phytostabilization of these areas has been proposed as an effective measure to avoid

According to the research priorities within the actual Spanish National Programmes, a detailed study about the soil-water-plant interactions in areas with high biodiversity is proposed. The research will be developed in two salt-marshes located in the coastal area of the Mar Menor (SE Spain). These sites are characterised by soils polluted by metal mine wastes and by eutrophicated water flowing across them.

To achieve these objectives, a field work stage and a pot experiment were performed. The first field survey was focused on the description of the edaphic and ecological gradients along a transect from a control non-polluted site to the mine tailings. The edaphic patch distribution was found to be determining for the selective establishment of spontaneous vegetation.

Specific objectives are:
1. Determine to what extent the decomposition of the "litter" from different plant species is influenced by the presence of high nitrogen, phosphorus and dissolved organic carbon contents in eutrophicated waters and if this is related to the season of the year in which flooding-drying phases ocurr

The Intergovernmental Panel on Climate Change (IPCC) predicts increasing levels of atmospheric CO2 and air temperatures as well as decreasing soil moisture, the soils being among the most affected components of terrestrial ecosystems, especially in the Mediterranean area. Due to the importance of soil functions (organic matter/nutrient cycling, productivity, etc.), its response against such changes is crucial for assessing how terrestrial ecosystems might adapt and/or contribute to mitigate global warming.

The risks of toxicity by metals/metalloids due to mining wastes pollution take place in the mine tailings, but also in lowland areas such as wetlands due to the erosion of the tailings and the transportation of wastes to these topographically depressed positions. In this Project, we work in field and experimental conditions, performing toxicity tests with seeds, seedings, young/adult plants and soil invertebrates.

Groundwater withdrawal by desalination plants might lead to a drop of the piezometric levels of aquifers,causing negative impacts, especially in water-dependent ecosystems. Management strategies are necessary to overcome these potential problems, particularly in abandoned solar saltworks, wetlands which are particularly prone to degradation by desiccation. This proyect aims to asses a pioneer programme of irrigation with seawater to correct the environmental impacts of two desalination plants in Agua Amarga salt marsh, SE Spain.

A detailed study of soil-plants-hydromorphy interactions is proposed which includes ecotoxicologycal aspects jointly with the identification of biomarkers of pollution in areas with high biodiversity. The research will be developed in two salt-marshes located in the coastal area of the Mar Menor (SE Spain). These sites are characterised by soils polluted by metal mine wastes, they have a high biodiversity and they suffer an intense human pressure.