We develop new cost-effective techniques, such as QuickScan sampling (e.g. activity traps, eDNA), that are applicable in effective monitoring schemes in space and time. Water quality assessment is innovated using trait-based diagnostic tools (e.g. Multimetric Amoebe), passive sampling and effect-directed analysis.
Examples of projects
- Typology: Limburg, Gelderland, Overijssel, Natuurdoeltypen, beheertypen Index NL
- Assessment: EU-AQEM, EU-STAR, Definitiestudie KRW, Graadmeters aquatische natuur, Kaart aquatische natuur, MNP graadmeters
Monitoring: KRW monitoring, SNL monitoring
- Methods: MEP-GEP natuurdoelen, KRW Verkenner, Quick-Scan Rivierenland, QuickScan Rijnland, macrofaunacursus
Both national and European approaches to assess ecological water quality require an unbiased estimate of the quality exceeding that of a single site or reach. The selection of sampling sites is often based on its assumed representativeness for the entire water body or on more practical matters, like accessibility of the site. The problem with such a non-probability site choice is that statistically-based inferences about trends at higher/lower spatial scales cannot be made and the selection bias can result in erroneous conclusions. Probability sampling is well suited to eliminate selection bias since, by construction, every site has a known nonzero probability of being selected. Since we are obliged in the Netherlands to make inferences at water body/national level we need to apply probability sampling to draw statistically sound conclusions. By developing a ‘Quick Scan’ methodology that can be used in a probability sampling scheme to scan larger regions for ecological problems both cost-effectiveness and spatial coverage are strongly improved.
Multimetric AMOEBE: diagnostic assessment tool
Tools to not only assess but also to diagnose the ecological status of streams and drainage ditches in The Netherlands are currently lacking. Therefore, multimetric indices based on functional features of macroinvertebrates were developed. Based on a large datasets from regional water district managers degradation gradients were composed. Subsequently, a stepwise process was used to evaluate the discriminatory efficiency of a variety of diversity, abundance/ composition, tolerance/ sensitivity, and functional metrics for assessing ecological degradation. After evaluating metric range, strength of correlation to the stressor gradient, degree of redundancy, and sample- and seasonal repeatability, metrics were selected for incorporation into the multimetric index. We represent the multimetric-indices graphically with the AMOEBE technique, to provide a quick overview of the relative contribution of different types of disturbances to ecological degradation.
Smart passive sampling by using activity traps
We tested the effectiveness of activity traps for macroinvertebrate monitoring in shallow, heavily vegetated drainage ditches was tested. Based on the taxon accumulation curves, a trapping duration of 168 h was highly efficient and resulted in a large number of taxa collected. Of the attractants offered in the traps, only bait caused differences in the macroinvertebrate assemblage recorded when short trapping time was used. Because of their relatively low labour requirements and high level of standardization, activity traps appear to be a valuable tool in lentic biodiversity surveys, especially when deployed for a longer period than has usually been reported. The use of bait is advisable only if capture of specific taxa is required and not for standard monitoring purposes.
- Verdonschot, R.C.M., Keizer-Vlek, H.E., Verdonschot, P.F.M. (2012) Development of a multimetric index based on macroinvertebrates for drainage ditch networks in agricultural areas. Ecological Indicators 13: 232-242
- Keizer-Vlek, H.E. , Verdonschot, P.F.M. , Verdonschot, R.C.M. , Goedhart, P.W. (2012) Quantifying spatial and temporal variability of macroinvertebrate metrics Ecological Indicators 23 (2012) ISSN 1470-160X - p. 384 - 393
- Verdonschot, R.C.M. (2010) Optimizing the use of activity traps for aquatic biodiversity studies. Journal of the North American Benthological Society 29(4): 1228-1240
- Verdonschot R.C.M., Keizer-Vlek H.E. & Verdonschot P.F.M. (2011) Biodiversity value of agricultural drainage ditches; a comparative analysis of the aquatic invertebrate fauna of ditches and small lakes. Aquatic Conservation: Marine and Freshwater Ecosystems (2011) 21: 715-727
- Verdonschot, P.F.M. (2006) Beyond biological monitoring: an integrated approach. In G. Ziglio, M. Siligardi, & G. Flaim (eds), Biological monitoring of rivers; applications and perspectives (Water Quality Measurements Series) (pp. 435-459). Chichester (UK): John Wiley
Publications, tools, presentations
- Keizer et al (2013) KRW QuickScan macrofauna ‘overige wateren’. H2O 1306-01
- Verdonschot P., Nijboer R. & Elbersen J. (2004) Integratie van water en natuur door Kaderrichtlijn Water, Waternood en Natuurdoeltypen. H2O 37 (6): 21-23
- Elbersen J., Verdonschot P., Nijboer R. & Hartholt H. (2003) Typologie, maatlatten en referenties bij Kaderrichtlijn Water. H2O 36 (20): 24-27
- Nijboer R. & Verdonschot P. (1999) Natuurwijzer water. H2O 21: 19-21