Mapping the condition of Queensland’s grazing lands

Abstract

Grazing land condition is the ability of grazing land to convert rainfall into useful forage and is determined by changes in pasture, soil, and woodland condition. The Grazing Land Management framework defines four condition classes (A, B, C or D), indicating maintenance of 100%, 80%, 50% and 20% of productive potential respectively. The Queensland Government is currently funding a six-year program to map grazing land condition in key Great Barrier Reef catchments. The work incorporates assessment of thousands of grazing land sites using the Land Condition Assessment Tool (LCAT), modelling the ABCD land condition class at those sites and generating modelled land condition maps across the targeted regions. Modelling and mapping land condition across large areas presents some significant challenges. For example, land condition is a multidimensional outcome that can be hard to mathematically fit to a unidimensional scale like ABCD, and spatial data that might predict some of these dimensions is either absent or limited. This has led the project to investigate and trial a number of approaches to delivering land condition mapping. This paper outlines the project’s progress and some of our key learnings so far. These include an outline of LCAT sampling to date, an overview of the modelling and validation process and details around the planned rollout of the mapping.