The impact of anthropogenic soil sealing on the soils of protected coastal lagoons (Albufera de Valencia, Spain)

Abstract

Anthropogenic soil sealing is one of the most worrying soil degradation factors to European level. Its development is a persistent threat in Mediterranean environments where socio-economic changes have produced the concentration of most productive activities in the alluvial coastal plains. Such trends may also affect soils in protected coastal lagoons. In this work a methodology based on the spatial and temporal analysis of artificial layers (concrete, asphalt, etc.) is developed. Data used have consisted in the extraction of soil sealing covers in polygon layers for the years 1991 and 2007, a layer with municipal limits and a layer with the limits of the protected area of the Albufera Natural Park, the study area located to the south of the city of Valencia, Spain. The analysis has consisted in the development of a set of statistics describing the situation of soil sealing and land fragmentation, understanding the first as the direct measure of soil losses and the later as a measure of loss of soils functionality. Results show that in 1991almost 15% of the total administrative area studied was sealed and that it has increased to almost 19%, with variable trends according to individual municipalities. Such behaviour is identified in the soil of the protected area with smaller values, ranging from 3.75% in 1991 to 5.20% in 2007. The extension of the sealed surfaces has been also reflected in the fragmentation of soils with a considerable increase of soil patches and the subsequent reduction of their average size.