Several factors can impact aquatic ecosystems within catchment and it can be difficult to untangle the effects of pollution from other influences. Using a multiple lines of evidence approach, CAPIM can identify what factors are causing impairment to aquatic ecosystems. This is achieved using a range of methods, including:
- Biological assessments (e.g. habitat surveys, ecosystem health evaluations, laboratory and field-based ecotoxicology)
- Chemical assessments (monitoring, pollution sourcing and the development of passive samplers).
Identifying the causes of ecosystem stress enables managers to prioritise areas for further investigation or remediation, and to ensure resources are directed towards solutions that provide better, cost-effective outcomes for the environment, such as with environmental offsets.
Examples of catchment based assessments conducted by CAPIM include:
- Dandenong Creek: Identifying the primary factors influencing aquatic ecosystem health (heavy metal pollution, episodic sewage discharge, habitat).
- Western Port: Pesticide sourcing and aquatic flora and fauna assessment (habitat, pesticide pollution).
- Jacksons Creek: Identifying the factors influencing aquatic ecosystem health (urban pollution, wastewater discharge, agricultural runoff, flows, habitat).
- Merri Creek: Linking land-use activies to point source pollution to assess the ecological degradation of the creek.