Impact of land use in catchment and human activities on water, sediment and vegetation of Mediterranean temporary pools.

The vegetation and physical and chemical characteristics of the water and sediment in ten temporary pools submitted to various anthropogenic disturbance were studied in Morocco over two hydrological cycles (1997-1998 and 1998-1999). Results of multivariate and parametric analyses show that disturbance has a significant impact on water and sediment. Agriculture in the catchment resulted in higher levels of N and the use of detergent to higher levels of phosphorus in both water and sediment. Mineral extraction resulted in higher depth and longer duration of flooding. Vegetation characteristics were better correlated to hydrology (water depth, duration of flooding) than to nutrient variables. These results suggest that although agriculture in the catchment contribute in modifying the sediment characteristics, the impact on vegetation and its conservation value is limited. However, care should be taken of the long-term effects of agriculture through cumulative effects and of the possible consequences of changing the agricultural practices.