A Field Guide to Assessing Australia’s Tropical Riparian Zones through the National Action Plan for Salinity and Water Quality (Tropical Rapid Appraisal of Riparian Condition (TRARC))
Description and method logic
TRARC is a user friendly field-based method to quickly assess riparian condition, in Tropical Australia, at small scales (100mt), i.e. sections of creeks and rivers that are less than 10km long.
This Field Guide draws on Tropical Savannas CRC research first published by Land & Water Australia.
The TRARC provides a standardised approach to assessing riparian health that can be used by a broad range of user groups. It can be used to rapidly assess the health of riparian locations across tropical areas in northern Australia. The TRARC is a visual assessment of the riparian zone immediately adjacent to creeks and rivers. It is not designed for floodplains or wetlands. Indicators are grouped into five categories (sub-indices) that can be analysed individually or combined to give an overall score (1-5) for the study area.
The TRARC assesses the ecological condition of riparian habitats using indicators that reflect functional aspects of the physical, community and landscape features of the riparian zone. The method describes a field-based approach to quickly assess riparian condition at small scales, i.e. sections of creeks and rivers that are less than 10km long.
This method is specifically designed for a 100m length of river bank (transect), and can be repeated several times within an area with the same management regime. The more assessments that are made, the more accurate the overall assessment of condition will be.
Assessments can be repeated over time to monitor changes in condition. The timeframe between these assessments will need to be trialled. A starting point would be at two to five year intervals.
TRARC requires the user to visually assess 21 indicators along a transect. These indicators are based on the functions of the riparian zone. Each indicator is given a score from 1-5 based on predefined condition categories. Indicator scores can be weighted. The entire assessment is a visual measurement of features (indicators) in and around the riparian zone that indicate good or poor condition. It also identifies threats or pressures to the riparian zone. Each indicator is given a score between 1 and 5.
Criteria groupings of the method
Cover: riparian width, canopy continuity, overstorey cover, ground cover, grass cover, bare grounds
Debris: fine woody, coarse woody, standing dead
Natives: overstorey, ground cover, grass, deleterious weeds
Regeneration: dominant canopy juveniles, sub-dominant juveniles, community structure
Disturbance: slumping erosion, gully erosion, fire impact, animal impact, other impact
Site surveys of: Vegetation cover and structural complexity, dominance of natives versus exotics, standing dead trees, fallen logs and leaf litter, indicative features erosion and other impacts.
TRARC is not resource intensive, requiring a practitioner to visually survey the transect area. Basic ecological knowledge, GIS, mapping and GPS skills may also be desirable, depending on the scope of the assessment.
Observers should be consistent and conduct all assessments. They may need to undertake some training beforehand, to ensure consistency of data collection. The observer will need to have some experience in discriminating native and exotic plant species, and may benefit from previous experience in habitat surveys.
TRARC general data entry spread sheet (see links). Access to supporting maps and information and land access. General survey equipment is required, as well as provisions for measuring vegetation, soil, hydrology attributes, maps, identification resources and if necessary GPS equipment.
The entire assessment is a visual measurement of features (indicators) in and around the riparian zone that indicate good or poor condition. It also identifies threats or pressures to the riparian zone. Each indicator is given a score between 1 and 5.
All the indicators that are assessed in the field are grouped into categories (sub-indices). The scores for
these indicators are summed together within their respective subindex (Plant Cover, Regeneration, Erosion and Weeds).
Pressure categories are summed and converted to a score, where a higher score implies greater pressure (or threats).
Criteria by category
Physical and chemical
The method and outputs can be used for a variety of applications by Government, NRM Groups and Non Government Organisations. Examples include determining relationships between riparian condition and management practices, or surveying overall condition within a catchment to determine priorities for future rehabilitation works in the catchment.
TRARC: Trialling of the Tropical Rapid Appraisal of Riparian Condition method in the Burdekin River catchment, northeast Queensland.
Dowe, J, Dixon, I & Douglas, M (2004), Trialling of the Tropical Rapid Appraisal of Riparian Condition method in the Burdekin River catchment, northeast Queensland. RipRap Edition 26.. [online], Land and Water Australia, Canberra. Available at:.
Last updated: 18 January 2021
This page should be cited as:
Department of Environment and Science, Queensland (2021) A Field Guide to Assessing Australia’s Tropical Riparian Zones through the National Action Plan for Salinity and Water Quality (Tropical Rapid Appraisal of Riparian Condition (TRARC)), WetlandInfo website, accessed 13 May 2021. Available at: https://wetlandinfo.des.qld.gov.au/wetlands/resources/tools/assessment-search-tool/a-field-guide-to-assessing-australia-s-tropical-riparian-zones-through-the/