Structure and association in the Mulga (Acacia aneura) lands of south-western Queensland

Abstract

Results of a detailed botanical survey in two mulga (Acacia aneura) areas of semiarid south-western Queensland are presented. Two 20 mile belt transects permanently identified for future relocation were used to record woody vegetation. The results for each of the study areas are interpreted by means of association analysis. Several site groups were recognized, in which increasing elevation from the flats to the ridges seems to be the main factor consistent with community changes. The density of seedling and young mulga is considered inadequate for future drought reserves at one site. No large species groups exist on either site, and both areas represent small mosaics. It is suggested that microtopography is an important determinant of species distribution in the sites studied.

Objective `Safe' Grazing Capacities for South-West Queensland Australia: Development of a Model for Individual Properties.

“…In south-west Queensland, inappropriate livestock numbers and pressure from unmanaged herbivores (feral goats, kangaroos and rabbits) have reportedly caused pasture degradation and productivity losses in the region. Concern over the decline in agricultural productivity of the region has been expressed by a number of authors e.g., Ratcliffe (1937), Burrows and Beale (1969), Pressland (1976Pressland ( , 1984, Mills (1986), Warrego Graziers Association (1988, Mills et al (1989), Miles (1989), Passmore and Brown (1992) and Anon. (1993).…”

Fire after a mast year triggers mass recruitment of slender mulga (Acacia aptaneura), a desert shrub with heat‐stimulated germination

“…This finding probably reflects that soils under these shrubs had not been heated sufficiently to break seed dormancy, irrespective of seedbank densities at the time of fire. In addition, it is likely that even if a small fraction of the seedbank of unburnt shrubs had germinated without heat‐stimulation (as often occurs in mulga seeds (Fox, 1985)), seedling emergence would have been impeded by the dense phyllode litter mats that characteristically occur on the ground layer of unburnt mulga stands (Burrows and Beale, 1969; Winkworth, 1973).…”

Development of Ecosystem Research

“…Canopy dynamics of overstorey strata and associated subshrubs were investigated in Acacia communities in the arid zone of South and Central Australia [125,126]. A thinning experiment to encourage the growth of the grassy understorey by reducing the density of mulga trees was established at Charleville in south-western Queensland [127,128]. The ability of C4 grasses, such as Astrebla spp., to survive desiccation in the arid zone-and to resurrect after rain-was explored [118,119].…”