Indicator organisms are those that can be collected or observed, and provide

 

insight into ecological processes within that system, the health of biological communities and/or the general health of the system as a whole. Aquatic macroinvertebrates (animals without spines) are one of the most commonly used indicator groups worldwide, and at Aquateco we often use these organisms during baseline and impact assessments.

 

As leaders in our field, we recognise both the strengths and limitations of macroinvertebrates, and we supplement or substitute other indicator organisms when these are more appropriate.These include:

 

• fish communities

• microcrustaceans (zooplankton)

• algae (attached and planktonic)

• diatoms (a special group of algae)

• aquatic vegetation, and

• estuarine / marine benthos.

 

Aquatic macroinvertebrates (animals without spines) are excellent indicators of waterway health because they:

 

• live in the water for most or all of their lives - often for more than a year

• have limited mobility and stay in areas suitable for their survival

• are easy to collect and identify

• differ in their tolerance to disturbance and integrate environmental conditions

 

Indicator organisms can tell us much more about the health of a system than water or sediment quality data alone, but to get the best information out of ecological indicators requires an excellent knowledge of aquatic communities and processes. Without this it is not possible to design and implement a sampling program that will give meaningful results.  Choosing the most appropriate indicators is the first step and is where most waterway managers go wrong, and it’s all downhill from there. For example, aquatic macroinvertebrates are routinely sampled by almost every organisation operating in areas where waterways are ephemeral, yet they are inappropriate indicators that reveal little about the health of these systems or the potential impacts of a project!

 

The use of ecological indicators in assessing and monitoring aquatic ecosystems is an area where Aquateco is exceptionally strong. We have led a large number of projects that use this approach, including:

 

• Upper Nerang Aquatic Ecosystem Health Assessment: South East Queensland.

• Bowen River Aquatic Ecology Baseline Survey: Central Queensland.

• Condamine River and Tributaries Aquatic Ecology Baseline and Impact Assessment: South East Queensland.

• Loogana Retention Ponds Ecological Health: Tasmania.

• Impacts of a Road Bridge Upgrade on Tidal Creek Ecology: South East Queensland