The exposure to toxicants is shaping the species composition of our streams. We develop the indicator system SPEAR which link community structure with the toxic pressure, and study the risk of ecosystems.
Species with certain physiological, behavioural and life cycle traits are particularly impaired by toxicants. For instance, recurring contamination with pesticides in spring affect especially species being present in the streams at this season and cannot recover due to long generation times.
The portion of such sensitive species ("SPEcies At Risk") indicates the toxic pressure in a stream . Unlike other indicator systems, this SPEAR index is based on traits instead of taxa, and therefore hardly disturbed by the naturally varying species composition, as well as by additional stressors .
The SPEAR concept was developed in this department and has been countinuously improved. The SPEAR and TU calculators are online available.
With this indicator system we study the risk of toxicants on the landscape level, as demonstrated in the model LanduseInformer. E. g. we model the effects of buffer strips or the influence of climate change on insecticide exposure of our watercourses .
- Liess M, Schäfer R, Schriever C, 2008. The footprint of pesticide stress in communities - species traits reveal community effects of toxicants. Science of the Total Environment, 406, 484-490.
- Beketov MA, Liess M, 2008. An indicator for effects of organic toxicants on lotic invertebrate communities: independence of confounding environmental factors over an extensive river continuum. Environmental Pollution, 156(3), 980-987.
- Kattwinkel M, Kühne J-V, Foit K, Liess M, 2011. Climate change, agricultural insecticide exposure, and risk for freshwater communities. Ecological Applications, 21, 2068–2081.