Ground Cover - Regional Comparison Report

For a selected Lot(s) on Plan in Queensland, the Ground Cover – Regional Comparison report:

• presents the seasonal ground cover levels for each of the dominant GLM land types for the selected Lot(s) on Plan.
• compares ground cover levels for these land types on the selected Lot(s) on Plan, with the same land types in the local region (within 25 to 50 km radius depending on the size of the property) from year 1990 to the present. This comparison can be made either as:
• percentage cover levels for both the land type on the Lot(s) on Plan and the same land type in the surrounding region.
• a ranking (percentile) against the region.

For more details, see the section - FORAGE Report: Ground Cover – Regional Comparison of the FORAGE User Guide (PDF, 2.8 MB).

This report provides information to:

• compare property ground cover levels against the surrounding region.
• identify land types which may be subject to high or low grazing pressure when compared to the district average.

• The information in this report can be used as:
  • an objective source for viewing property ground cover levels compared with others in the surrounding district.
  • a basis for discussion that may encourage further investigation of selected property cover levels (e.g. visually and in association with other FORAGE reports, such as the monthly Ground Cover report) to re-evaluate management of a particular land type.
  • motivation to re-evaluate management if percentile cover levels are lower than those in the surrounding district (in association with other FORAGE reports, such as the monthly Ground Cover report).
• If a significant management change date and a significant ownership change date are provided, they can be displayed on all cover graphs throughout the report.

• The Ground Cover – Regional Comparison report uses what is known as ‘fractional’ ground cover.
• An algorithm is applied to the Landsat satellite imagery which classifies the ground cover into the green and non-green cover components (or ‘fractions’), and bare ground.
• The green and non-green fractions are summed to obtain total cover. The non-green ground cover levels reported may also include grass or tree litter (a useful component for soil enrichment and adds protection against erosion) but may not offer useful nutrition content to livestock. Equally, the green fraction will be a composite of all plant types and could include undesirable pasture species or weeds.
• The satellite imagery does not distinguish between pasture composition, biomass or feed on offer.

• Seasonal ground cover data is derived by gathering imagery over a season to produce a composite image that is representative of the median levels of cover measured throughout the season.
• The ground cover value reported is the median of the range of measured values within the 3-month season.

The calculation excludes areas identified, based on Queensland Land Use Mapping Program (https://www.qld.gov.au/environment/land/vegetation/mapping/qlump/) data, as non-grazed areas such as national parks. Stock routes are also excluded from the calculation.

• High tree cover areas (>45% tree foliage projected cover) are excluded from the calculation due to difficulties of assessing ground cover in such areas.
• The selected Lot(s) on Plan is also excluded from the calculation of the regional percentiles.

• The use of a 25 km localised radius is used generally for property comparison. It is intended to reduce the influence of climate variability on any comparisons as it assumes the local region will have experienced similar rainfall and climate.
• When properties are larger, a 50 km radius is considered ‘local enough’ to reduce regional rainfall effects, but broad enough to include a large enough region to make a meaningful ground cover comparison.
• Beyond a 50km radius may lead to an inaccurate comparison analysis, due to differences in rainfall or ecological systems.