Ramblas in south-east Spain:: threatened and valuable ecosystems

1. The term 'rambla' defines watercourses with specific geomorphological features that make them different from all other temporary streams. Most ramblas represent extreme habitats for plants and animals that have to be adapted to high salinity and extreme hydrological fluctuations with severe dry periods and floods. Both factors shape the structure and functioning of the whole aquatic ecosystem. 2. Biological communities in ramblas are diverse and rich in endemic species. Habitats of interest within the EU are extensively represented in ramblas and their associated wetlands. Ramblas also fulfil previously unrecognized functional and cultural values, such as helping to control non-point-source pollution in agricultural areas and to provide a variety of historic and educational resources. However, they are a threatened ecosystem because of the diversity of uses and derived impacts. 3. To characterize and describe the diversity of ramblas in south-east Spain, an extensive survey was carried out in 2000-2001 in the province of Murcia. Based on the lithology where ramblas are located, they were grouped in three categories: ramblas of marl, limestone and metamorphic basins. 4. Rambla categories differ in structural parameters, hydrology, water chemistry, biological communities and their vulnerability to a range of human impacts, thus requiring a flexible approach to their management and conservation. Copyright (C) 2005 John Wiley & Sons, Ltd.