The contribution of macroalgae to the assessment of the ecological quality of the rivers in Wallonia based on macrophytes indicator values in the British and French approaches.

In accordance with the water Framework Directive (WFD, European Parliament & The Council of the European Union, 2000) defining the overall ecological status of rivers, many hundred sites were analysed in the Walloon network. Within each sample, macroalgae data were gathered at species/or at genus level and the main water quality parameters were collected several times per year from 2005 to 2009.
<br /><br />Seventeen species and genera cited in the French and English lists of macrophyte methods used to assess the ecological quality of rivers were considered. Within these sites, the ratio of the macroalgae among the contributory species was examined and the impact of these on the final scores of the River Macrophytes Nutrient index (United Kingdom, Wilby et al.,2006) and the biological macrophytic index in rivers (France, Haury et al., 2006) was analysed.At the same time, a ranking of these macroalgae along a trophy gradient has been established thanks to a principal component analysis of the physico-chemical parameters and a weighting of the species presence in a given waterbody by its abundance.The relationships between macroalgae scores and those found in France and in United Kingdom were studied using the Spearman rank correlation coefficient.
<br /><br />Literature:
<br /><br />European Parliament & The Council of the European Union, 2000. Directive 2000/60/EC of the European Parliament and of the Council establishing a framework for the Community action in the field of water policy. Official Journal of the European Communities 327: 1-72.Haury, J., M.-C. Peltre, M. Trémolières, J. Barbe, G. Thiébaut, I. Bernez, H. Daniel, P. Chatenet, G. Haan-Archipof, S. Muller, A. Dutartre, C. Laplace-Treyture, A. Cazaubon & E. Lambert-Servien, 2006. A new method to assess water trophy and organic pollution – the Macrophyte Biological Index for Rivers (IBMR): its application to different types of river and pollution. Hydrobiologia 570: 153-158. Willby, N., J. Pitt & G. Phillips, 2006. Summary of approach used in LEAFPACS for defining ecological quality of rivers and lakes using macrophyte composition. Draft Report January 2006.