Impacts of Water Scarcity and Drought on Iberian Aquatic Ecosystems

Abstract

The climate of most of the Iberian Peninsula (Spain and Portugal) is Mediterranean and undergoes cyclical droughts. Climate change in this region will likely exacerbate the frequency and span of droughts. The historical development of irrigation and the recent economic development put additional pressure on the scarce freshwater resources. Consequently, most of the rivers, lakes, estuaries, and wetlands are impacted by the reduction and regularization of the flow regime and overexploitation of aquifers, especially in the south and on the Mediterranean coast. The main responses of Iberian aquatic ecosystems to increased water stress are reported to be: changes in biotic community structure, changes in habitat availability, alteration of ecosystem metabolism, increase of eurytolerant and invasive species, increase of pollution, and reduced resilience against global change impacts. One of the main measures to be implemented for mitigating the effects of water scarcity in Mediterranean aquatic ecosystems is the establishment of a proper environmental flow regime. Future research should focus on quantifying the ecological effects of water scarcity and the role of environmental flows in maintaining ecosystem structure and function.