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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))

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Developer

Tropical Savannas CRC with the West Australian State and Australian Governments through the National Action Plan for Salinity and Water Quality

Latest documentation

2015

Designed for use in

Australia

Ongoing

Yes

Assessment purpose

Condition, Prioritisation, Processes and components

Assessment criteria

Physical and chemical, Flora

Method type

Field

Timescale

Rapid term – The methodology a field-based method to quickly assess riparian condition at small scales,

Scale

Landscape/Catchment, Site/habitat

Wetland system

Riverine

Description and method logic

Method purpose

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.

Summary

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.

Method logic

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

Data required

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.

Resources required

Expertise required

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.

Materials required

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.

Method outputs

Outputs

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).

Uses

  • Determining relationship between riparian condition and land management practices
  • Determining priorities for rehabilitation works in the catchment
  • To evaluate the effectiveness of existing programs
  • To prioritise works for future programs.

Criteria by category

    Physical and chemical

    • Disturbance
      • Animal impact
      • Fire impact
      • Gully erosion
      • Other impact
      • Slumping erosion

    Flora

    • Cover
      • Bare ground
      • Canopy continuity
      • Grass cover
      • Ground cover
      • Overstorey cover
      • Riparian width
    • Debris
      • Coarse woody
      • Fine woody
      • Standing dead
    • Natives
      • Deleterious weeds
      • Grass
      • Ground cover
      • Overstorey
    • Regeneration
      • Community structure
      • Dominant canopy juveniles
      • Sub-dominant juveniles

Review

Recommended user

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.

Strengths

  • Has been extensively trialled across northern Australia
  • Easily interpretable results
  • Can be modified for specific projects.

Limitations

  • Criteria are largely qualitative
  • Weightings can be adjusted to give prejudicial results, reducing objectivity
  • Results can be affected by seasonal changes, fluctuations in stocking rates, natural flow of plant dispersal, establishment, growth and senescence
  • Best suited for savanna streams with a well-defined channel, further research and field validation is required for different river types
  • Caution is needed when interpreting the final score.

Case studies

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: https://wetlandinfo.des.qld.gov.au/resources/static/pdf/assessment-toolbox/riprap-26.pdf.

Links


References

  1. Dixon, I & Douglas, M (2007), A Field Guide to Assessing Australia’s Tropical Riparian Zones.. [online], Tropical Savannas CRC, Darwin. Available at: https://wetlandinfo.des.qld.gov.au/resources/static/pdf/assessment-toolbox/field-guide-assessing-australia-tropical-riparian-trarc.pdf.
  2. Dixon, I, Douglas, M, Dowe, J & Burrows, D (2006), Tropical Rapid Appraisal of Riparian Condition Version 1 (for use in tropical savannas). [online], vol. River and Riparian Land Management Technical Guideline, no. 7., Land and Water Australia, Canberra. Available at: http://lwa.gov.au/products/pr061169.
  3. Dixon, I, Douglas, M, Dowe, J, Burrows, D & Townsend, S (2005), 'A rapid method for assessing the condition of riparian zones in the wet/dry tropics of northern Australia', Proceedings of the 4 th Australian Stream Management Conference: Linking Rivers to Landscapes, pp. 173-173-178, Department of Primary Industries, Water and Environment, Hobart, eds. I D Rutherford, I Wiszniewski, M Askey-Doran & J R Glazik.

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/

Queensland Government
WetlandInfo   —   Department of Environment and Science