Landsberg J (Cooperative Research Centre for Tropical Savannas Management, Cairns); Crowley G (Queensland Parks and Wildlife Service, Cairns)
0958101418
Rangeland; Savannas; Biodiversity; Biological indicators; Plants; Native plants; Exotics; Weeds; Introduced species; Species abundance; Species diversity; Spatial distribution; Geographical distribution; Botanical composition; Surveys; Case studies
Plants are relatively sensitive to many of the pressures acting on rangeland biodiversity and also relatively amenable to measurement. Metrics based on plants therefore have considerable potential as highly efficient indicators of rangeland biodiversity condition and should be included in biodiversity monitoring frameworks. A hierarchical approach that incorporates low intensity, broad-scale monitoring to provide context and high intensity local-scale monitoring to provide an understanding of processes is recommended. Seven of the eleven core set of indicators recommended by the National Land and Water Resources Audit (NLWRA) rely on plant-based metrics. These are: progress towards an adequate and representative reserve system, extent of clearing, cover of native perennial ground layer vegetation, the distribution and abundance of exotic plant species, the distribution and abundance of fire sensitive species, and the distribution and abundance of grazing-sensitive species. Case studies of thecurrent state of knowledge about the seven indicators in the Gascoyne-Murchison Strategy area and Cape York Peninsula showed it would be possible to monitor most of them at the regional scale. However, current monitoring programs fail to achieve that. The case studies also identified two possible additions to the set of indicators: explicit indicators of grazing pressure and fire regimes and explicit inclusion of minimally disturbed reference areas to provide a standard against which to assess the biotic integrity of areas under pressure (A).
