Macrophyte communities in unimpacted European streams: variability in assemblage patterns, abundance and diversity

Macrophytes are an important component of aquatic ecosystems and are used widely within the Water Framework Directive (WFD) to establish ecological quality. In the present paper we investigated macrophyte community structure, i.e., composition, richness and diversity measures in 60 unimpacted stream and river sites throughout Europe. The objectives were to describe assemblage patterns in different types of streams and to assess the variability in various structural and ecological metrics within these types to provide a basis for an evaluation of their suitability in ecological quality assessment. Macrophyte assemblage patterns varied considerably among the main stream types. Moving from small-sized, shallow mountain streams to medium-sized, lowland streams there was a clear transition in species richness, diversity and community structure. There was especially a shift from a predominance of species-poor mosses and communities dominated by liverwort in the small-sized, shallow mountain streams to more species-rich communities dominated by vascular plants in the medium-sized, lowland streams. The macrophyte communities responded to most of the features underlying the typological framework defined in WFD. The present interpretation of the WFD typology may not, however, be adequate for an evaluation of stream quality based on macrophytes. First and most important, by using this typology we may overlook an important community type, which is characteristic of small-sized, relatively steep-gradient streams that are an intermediate type between the small-sized, shallow mountain streams and the medium-sized, lowland streams. Second, the variability in most of the calculated metrics was slightly higher when using the pre-defined typology. The consistency of these results should be investigated by analysing a larger number of sites. Particularly the need of re-defining the typology to improve the ability to detect impacts on streams and rivers from macrophyte assemblage patterns should be investigated.

[1]  J. Svenning,et al.  A review of natural vegetation openness in north-western Europe , 2002 .

[2]  M. Winterbourn.  The river continuum concept — reply to Barmuta and Lake , 1982 .

[3]  R. Margalef,et al.  Information theory in ecology , 1958 .

[4]  Leonard Sandin,et al.  Overview and application of the AQEM assessment system , 2004, Hydrobiologia.

[5]  Tenna Riis,et al.  Historical changes in species composition and richness accompanying perturbation and eutrophication of Danish lowland streams over 100 years , 2001 .

[6]  R. Butcher.  Studies on the Ecology of Rivers: I. On the Distribution of Macrophytic Vegetation in the Rivers of Britain , 1933 .

[7]  M. Trémolières,et al.  Aquatic macrophyte communities as bioindicators of eutrophication in calcareous oligosaprobe stream waters (Upper Rhine plain, Alsace) , 1990, Vegetatio.

[8]  P. Verdonschot,et al.  Testing the European stream typology of the Water Framework Directive for macroinvertebrates , 2004, Hydrobiologia.

[9]  K. R. Clarke,et al.  Statistical Design And Analysis For A Biological Effects Study , 1988 .

[10]  C. Preston.  Pondweeds of Great Britain and Ireland , 1995 .

[11]  C. Mesters.  Shifts in macrophyte species composition as a result of eutrophication and pollution in Dutch transboundary streams over the past decades , 1995 .

[12]  P. Verdonschot,et al.  Establishing reference conditions for European streams , 2004, Hydrobiologia.

[13]  Jan Lepš,et al.  Multivariate Analysis of Ecological Data , 2006 .

[14]  Mark V. Lomolino,et al.  Species Diversity in Space and Time. , 1996 .

[15]  S. Larsen,et al.  Plant distribution and abundance in relation to physical conditions and location within Danish stream systems , 2001, Hydrobiologia.

[16]  P. Legendre,et al.  SPECIES ASSEMBLAGES AND INDICATOR SPECIES:THE NEED FOR A FLEXIBLE ASYMMETRICAL APPROACH , 1997 .

[17]  M. Barrat-Segretain.  Strategies of reproduction, dispersion, and competition in river plants: A review , 1996, Vegetatio.

[18]  K. Sand‐Jensen,et al.  Plant communities in lowland Danish streams: species composition and environmental factors , 2000 .

[19]  P. Chambers,et al.  Habitat partitioning in riverine macrophyte communities , 1996 .

[20]  A revised classification system for British rivers based on their aquatic plant communities , 1998 .

[21]  Andrea Buffagni,et al.  The Development of a System to Assess the Ecological Quality of Streams Based on Macroinvertebrates – Design of the Sampling Programme within the AQEM Project , 2003 .

[22]  S. Haslam.  River plants of western Europe , 1978 .

[23]  J. Wilson,et al.  Methods for fitting dominance/diversity curves , 1991 .

[24]  M. O'hare,et al.  Community Structure of In-Stream Bryophytes in English and Welsh Rivers , 2005, Hydrobiologia.