The MARS Diagnostic Analysis Tool: diagnosing the causes of ecological degradation
The MARS Diagnostic Analysis Tool visualises probable multiple stressor occurrence based on ecological data from a water body.
Rivers and lakes across Europe are subject to multiple human stressors, which can interact to impact freshwater ecosystem health and status. As a result, a key problem for environmental managers seeking to conserve and restore water bodies is identifying the multiple causes of ecological stress and degradation.
Modern ecological assessments are increasingly sophisticated and informative, but they generally do not give a picture of the causes of multiple human stressors acting on an ecosystem. This is because such assessments are generally ‘integrative’ and do not focus on individual stressors.
Over the last four years, the EU MARS project has developed a Diagnostic Analysis Tool (DAT) to help water body managers and policy makers to identify and rank potential causes of ecological degradation at the catchment, reach and water-body scale.
The DAT is freely accessible through the online Freshwater Information Platform. Users can enter values or ranges of biological metrics which indicate ecological status in a water body. Metrics that can be inputted into the DAT include community-based indices (e.g., percentage of EPT macroinvertebrate taxa), assessment indices (e.g., saprobic index) and ecological traits (e.g., feeding types).
The DAT uses a Bayesian network to calculate the probability of different causes of ecological degradation being present in a water body. This probability can be visualised through graphs and tables. In effect, the DAT works like a doctor’s ‘health check’ for water bodies, in which the causes of illness are diagnosed based on a patient’s symptoms.
The DAT ‘diagnoses’ the probable causes of ecological degradation, based on their inputted ecological ‘symptoms’. Possible drivers of multiple stressors – arable and urban land use, riparian degradation, channel straightening, flow regulation, fine sediment pollution, habitat loss – are ranked in order of probability.
Descriptions of each driver, and possible mitigation approaches, are then provided through the tool’s interactive interface. This provides potentially valuable information for water managers seeking to minimise biodiversity losses and ecosystem alterations in their water bodies.
The DAT has been developed based on MARS research and modelling for mid-sized sand-bottom lowland rivers of Central Europe. However, it can be tailored by interested users to work for other water body types. Full documentation on how to modify the DAT can be found here (pdf) and guidance can be given by MARS scientist Christian Feld by email.
The Freshwater Blog 