page_title: SPEARpesticides
section_title: Calculation
hierarchical_section_title: SPEARpesticides / Calculation
caption_attribution_description: English: Concept diagram of the bioindicator SPEAR.
context_page_description: SPEARpesticides is a trait based biological indicator system for streams which quantitatively links pesticide contamination to the composition of invertebrate communities. The approach uses species traits that characterize the ecological requirements posed by pesticide contamination in running waters. Therefore, it is highly specific and only slightly influenced by other environmental factors. SPEARpesticides is linked to the quality classes of the EU Water Framework Directive
context_section_description: SPEARpesticides estimates pesticide effects and contamination. The calculation is based on monitoring data of invertebrate communities as ascertained for the EU Water Framework Directive (WFD). A simplified version of SPEARpesticides is included in the ASTERICS software for assessing the ecological quality of rivers. A detailed analysis is enabled by the free SPEAR Calculator. The SPEAR Calculator provides most recent information on species traits and allows specific user settings. 
  The SPEARpesticides index is computed as relative abundance of vulnerable 'SPecies At Risk' (SPEAR) to be affected by pesticides. Relevant species traits comprises the physiological sensitivity towards pesticides, generation time, migration ability and exposure probability. The indicator value of SPEARpesticides at a sampling site is calculated as follows:
  with n = number of taxa; xᵢ = abundance of taxon i; y = 1 if taxon i is classified as SPEAR-sensitive; y = 0 if taxon i is classified as SPEAR-insensitive.
  An application is available as download for PC. Web address to download the SPEAR calculator
caption: Concept of SPEARpesticides
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