Decline in grazing land condition in the Northern Gulf region of Queensland 1990–2018

Abstract

The cattle industry in the Northern Gulf region of Queensland, Australia, is based primarily on extensive grazing of native pastures on pastoral leasehold land. Large leasehold areas managed by few people make maintaining rangeland productivity and landscape function difficult for land managers. Seventeen discreet land types were identified and assessed across the Northern Gulf region over three periods (2004 [260 sites], 2012 [260 sites] and 2016 [252 sites]) to derive regional trends in rangeland condition. Further, detailed data from Queensland state-government QGRAZE sites (1992–2018) were analysed to assess long-term land condition changes on identified ‘at risk’ land types. Land condition attributes monitored included woodland thickening, pasture composition, soil surface condition and exotic weed incidence. Last, remote sensing was used to analyse woody cover dynamics across 23 regional land types and 30 QGRAZE sites from 1990 to 2018. Combined, analyses showed continued land condition decline across the region. Since 2004, the proportion of retained original carrying capacity is estimated to have declined from 72% to 66%. Land condition of high-value land types was slightly lower than that of low-value types. Estimates suggest that 50% of original carrying capacity will be lost by 2046 if current land condition trends continue, with the primary degradation factors being loss of preferred pasture species and woodland thickening. These results are possibly replicated in other extensively grazed regions of Queensland; however, lack of objective data suggests the need for an expanded monitoring program and a concerted response to address continuing land condition decline. The recommended hybrid monitoring methodology, including historical data, rapid assessments and remote sensing is low-cost, and could effectively be implemented elsewhere to show land condition change without needing to collect management information. Remediation will not be possible without the active engagement of industry, government and agencies. Effective management practices are discussed.