Modelling the effects of land use change on the nutrient dynamics in a coastal agricultural watershed: the Mar Menor case (Southeastern Spain)

Abstract

Martínez Fernández, J., Fitz, C., Esteve Selma, M.A., Guaita, N., Martínez-López, J. 2013. Modelling the effects of land use change on the nutrient dynamics in a coastal agricultural watershed: the Mar Menor case (Southeastern Spain). Ecosistemas 22(3):84-94. Doi.: 10.7818/ECOS.2013.22-3.12.

An integrated modelling approach on the nutrient dynamics has been developed for its application in the agricultural watershed of the Mar Menor coastal lagoon (South-eastern Spain), in order to analyse the long-term effects of land-use change on the nutrients inputs into the lagoon and associated wetlands. A lumped dynamic model has been developed which focuses on the socio-economic factors and land-use changes and their effects on the watershed-scale nutrient flows. In addition, a preliminary application of the ELM (Ecological Landscape Model), an eco-hydrological spatial dynamic model, has been carried out as an ongoing improvement of the hydrological modelling module. Simulation results for the 1970-2012 period showed a noticeable increase in nutrient inflows into the Mar Menor lagoon, highlighting the high inter-annual variability and the role of associated wetlands to remove part of the nutrients. The modeling approach was applied to explore the potential effects of several management measures aiming at reducing the export of nutrients from the agricultural fields into the Mar Menor lagoon, particularly studying measures to reuse agricultural leakages and plans for wetlands restoration. Results showed that wetlands restoration achieves a higher reduction in the inflow of nutrients into the lagoon, doubling those achieved by reusing agricultural leakages.