Assessment Framework

How the wetlands assessment framework works

The theory behind the framework is:

Human activities can affect components of wetlands and result in a component becoming a stressor on the ecosystem. Changes in pressures, acting through stressors can result in different condition responses.

The basic principle is:

For each individual stressor there are human activities that cause a change to an actual pressure acting on a wetland which in turn cause a change to the physical-chemical state of the system. This physical-chemical change results in a corresponding change (impact) to the biological condition of the wetland. There are pressure mediating factors (i.e. management practices) which reduce the likelihood of human activities impacting a wetland, as well as intrinsic mediating factors (i.e. a wetland’s vulnerability to a stressor) which determines the consequence of any change to a stressor.

Establishing Indicators for all of these elements (with a few exceptions) allows the risk of a wetland being affected by human activities as well as its current ‘level of’ health to be determined. Therefore, as the links between these elements, from human activities to biological impact, are better understood, the management activities needed to reduce the risk can be determined.

For example, for the stressor nutrients:

Note that there are many human activities and management practices that can affect the actual nutrient load that enters a wetland and that there are many condition responses that occur as a result of an increased nutrient load. A simple example is provided above.

Stressor based conceptual models

Stressors are defined as components of the environment that when changed can affect the condition of the ecosystem. For example, nutrients (the stressor) are naturally found in wetlands but the actual amounts entering the wetland, and hence the actual concentrations occurring in the wetland, can change as a result of human activities. Water run-off from crops which have had fertiliser applied can enter a wetland and alter its nutrient concentrations. A change in nutrient levels puts a stress on the system which may impact condition.

For each stressor a conceptual understanding of the links between human activities and wetland condition has been examined and conceptual models developed.

Identifying what stressor to monitor

Key stressors for particular wetland(s) need to be identified in order to determine what indicators to monitor.

One method is to look at the information provided in the stressor conceptual models and relate it to how the wetland functions, using the wetland conceptual models (natural process and components).

It can also be done by monitoring all the pressure indicators listed and determining the risk to the wetland in relation to each of the stressors. This process will take some time but most of the pressure information required should be relatively accessible and will result in the identification of the key stressors in an unbiased way. The condition indicators of only these key stressors can then be monitored, assessed and reported.

Identifying indicators

For each of the 14 stressors identified both pressure and condition indicators which link together and are specifically relevant to that stressor have been determined for monitoring. The recommended indicators are provided for each stressor in their conceptual models. The indicators are listed under six categories:

• stressor source (human activity)
• management practice
• direct pressure
• vulnerability
• physical-chemical state
• biological impact

Once a list of indicators, based upon relevant stressors, has been identified for a particular wetland(s)/region then a specific monitoring program for particular wetlands can be developed.

Scoring of indicators

To report on each indicator the assessment framework uses a scoring table based on a five point scoring scale, with a score of 1 being the ‘best’ and 5 the ‘worst’. The scores applied to condition indicators are generally based on how they compare to the guideline/reference or baseline value, or to the value obtained from the previous sampling period (trend/change data).

All scoring is based on current best understanding and uses information from the literature or expert knowledge. The actual scoring categories for each indicator are currently under review but can be examined by request from wetlands♲derm.qld.gov.au.

Assessment of risk and health

The primary purpose of a monitoring program using indicators identified through the processes described here is to provide information about the risk to, and health of, a wetland. The assessment framework allows scores of individual indicators to be combined to give overall risk and condition scores for each stressor, as well as the risk to, and health of, the wetland as a whole. The assessment framework allows indicators to be weighted and stressors ranked in addition to reporting on data confidence and dependability (i.e. how many indicators have been monitored and used in the final risk and health assessment).

A software system that performs all the necessary calculations and provides a report card output has been developed and is currently undergoing trialing. The software, called VPSIRR, also provides much of the background information needed to perform an assessment. For further information on VPSIRR please contact wetlands♲derm.qld.gov.au.