Bryofloristic evaluation of the ecological status of Madeiran streams: Towards the implementation of the European water framework directive in Macaronesia)

摘要

The EU Water Framework Directive legislates for sustainable, catchment level water management across the European Union. Principal goals of the Directive are that water bodies achieve Good status by 2015 and the use of biological quality elements in routine monitoring of surface water bodies. The bryophytes form a significant biotic component of riparian systems and can be associated with particular environmental conditions. Detailed studies on riparian Macaronesian bryophytes are lacking, in particular on the island of Madeira. This study outlines associations between within-stream bryophytes and key physicochemical water parameters in the streams of Madeira island. Bryofloristic characterization, results of ecological status and conservation interest of the habitats from Madeira's principal streams, describing possible measures for the sustainable management of these areas are covered. Bryophytes were found to be effective bioindicators of water quality in these unique Macaronesian riparian habitats and suitable biological quality elements for WFD compliant biomonitoring programmes. Results show that stream reaches classified as having High Ecological Status were mostly located on the northern slopes of the island, in upstream sections ot the streans, where the indigenous Laurisilva or heath forests predominate. These areas represent reference conditions forming the basis for the development and implementation of future restoration measures in degraded streams with the same typology. Sections classified as having Bad Ecological Status were situated in urban areas with higher levels of human intervention, subjected to various types of contamination which was reflected in the physicochemical parameters. Such areas are clearly degraded and should be restored through programmes of measures laid out in mandatory WFD River Basin Management Plans. The findings from this study present a contribution towards achieving Good ecological status as stated in the WFD, based on the Madeiran bryoflora.