Development of an Index for the assessment of biocenotically relevant river habitat structures
In a project for the Northrhine-Westphalian Environmental State Agency (LANUV NRW) chromgruen and umweltbüro essen developed a method, which improves the usability of river habitat data for the analysis of biocenotic analyses. The result is published in the August issue of Korrespondenz Wasserwirtschaft (Foerster, J., Halle, M. und Müller, A. (2017): Entwickung eines Habitatindex zur Beurteilung biozönotisch relevanter Gewässerstrukturen. Korrespondenz Wasserwirtschaft 8/2017, S. 466-471).
The habitatindex is defined as a combination of biocenotically relevant parameters of the river habitat survey method of LANUV NRW. Parameters were selected with regard to functional criteria with subsequent statistical validation.
Starting point of this development was an analysis to identify hydromorphological components that show strong responses of biological elements as defined in the WFD. Research was based on comprehensive sets of biological, chemical as well as hydromorphological monitoring data.
It was shown that although some parameters of river habitat survey show quite strong correlations to ecological state assessments these correlations do not represent relevant cause-effect-relations, because the impacts are only indirect (e.g., land use, river curvature). On the other hand the developed habitat index not only showed stronger correlations. The correlations were also the consequence of immediate functional effects.
The task was part of a perennial project where multiple ecological aspects were researched based on biological, chemical and hydromorphological monitoring data. Results are to be published in 2017 as a LANUV report.
The authors will present some of the results in this year's conference of German Society of Freshwater Science – DGL (25. bis 29.9.2017 in Cottbus).