The relative influence of catchment, riparian corridor, and reach-scale anthropogenic pressures on fish and macroinverte
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WATER BODIES IN EUROPE
The relative influence of catchment, riparian corridor, and reach-scale anthropogenic pressures on fish and macroinvertebrate assemblages in French rivers Anahita Marzin • Piet F. M. Verdonschot Didier Pont
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Received: 9 February 2012 / Accepted: 7 July 2012 / Published online: 24 July 2012 Ó Springer Science+Business Media B.V. 2012
Abstract This study compares the relative influences of physiography and anthropogenic pressures on river biota at catchment, riparian corridor, and reach scales. Environmental data, catchment and riparian corridor land use, anthropogenic modifications and biological data were compiled for 301 French sites sampled from 2005 to 2008. First, relationships between anthropogenic pressures and fish and macroinvertebrate assemblages were analysed using redundancy analysis. Second, the influences of physiography and the three scales of human pressures on biological assemblages were measured using variance partitioning. Distributions of fish and macroinvertebrate taxa along the pressure gradients agreed with bio-ecological knowledge. At the reach scale, assemblage variability among the 301 French sites was related to the presence of an impoundment and to poor water quality, while at larger scales it was linked to a gradient from forest to
Guest editors: C. K. Feld, A. Borja, L. Carvalho & D. Hering / Water bodies in Europe: integrative systems to assess ecological status and recovery A. Marzin (&) D. Pont Irstea, UR HBAN, HYNES (Irstea-EDF R&D), 1 rue Pierre-Gilles de Gennes, CS 10030, 92761 Antony Cedex, France e-mail: [email protected] P. F. M. Verdonschot Alterra, Wageningen University and Research, P.O. Box 47, 6700 AA Wageningen, The Netherlands
agricultural covers. In addition, a large proportion of the explained variability in assemblage composition was related to complex interactions among factors (*40%) and to physiographic variables (*30%). Furthermore, our results highlight that catchment land use better reflects local water quality impairments than hydromorphological degradations. Finally, this study supports the idea that human pressure effects on river communities are linked at several spatial scales and must be considered jointly. Keywords Redundancy analysis Land use Human pressures Fish Macroinvertebrate
Introduction At the river reach scale, aquatic biota respond to local environmental factors (e.g. physical habitat and water chemistry), that in turn are influenced by larger-scale pressures, such as riparian corridor condition or catchment land uses (Frissell et al., 1986; Poff, 1997; Angermeier & Winston, 1998; Bedoya et al., 2011). For instance, declines in forest cover and increases in agricultural and urban land uses are frequently related to degraded riverine habitat and biota (Allan et al., 1997; Snyder et al., 2003; Buck et al., 2004; Kroll et al., 2009). An increase in agricultural land use often results in nutrient enrichment and riffle sedimentation (Richards & Host, 1994; Snyder et al., 2003). Accordingly, the idea that
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