bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil water storage in a semi-arid Eucalyptus populnea woodland invaded by woody shrubs, and the effects of shrub clearing and tree ringbarking.
Authors: Johns GG
Published: December 2005

Soil water was monitored over a six year period in an intact shrub invaded semi-arid Elrcalyptlts popztlrlea woodland (control) and on areas which had been treated by either shrub-clearing, or by ringbarking of trees and shrub-clearing. Measurements were made under both the shrubby thicket areas near the eucalypt, and the sparsely shrubbed interthicket areas more distant from the trees. Average soil water storage over the six years for all treatments was only 26 nun. Much of this water was stored in the upper 500 Inm of the profile and hence was susceptible to direct evaporation from the usually bare soil surface. In the intact n.oodland and following wet weather, significantly more soil water was stored under thickets than under the interthicket areas. With the return of dry weather this cxtra soil water was rapidly depleted, and thicket soils would often become drier than interthicket soils. After pro- longed dry weather, soil matric potentials of - 10 to -1 2 MPa were recorded at a depth of 500 mm. Matric potentials by this time were least negative under thickets. Shrub clearing without rinpbarking increased thicket and interthicket soil water storage by 17% and 2396 respectively. The ring- barking and shrub clearing treatment increased thicket profile storage more than that of the interthicket (81% and 64% respectively). The effect of ringbarkinp lvas often pronounced at a distance of 25 rn from the tree. The contrasting soil water response to the two treatments indicated that in this semi-arid environment only a relatively srnaU change in soil water balance may accrue from incomplete clearing. The ren~oval of both shrubs and trees is probably necessary to make a large difference to soil water storage.
An economic study of the Western Division of N.S.W.
Authors: Davies L
Published: December 2005

The Hassall Report was based on an economic survey of 150 landholders throughout the Western Division of New South Wales for the financial years 197711978, 197811979 and 1979/1980. The survey used taxation records, however. some attitudinal informa- tion was collected from face to face interviews with landholders. The survey examined the financial performance in relation to the carrying capacity of the property and in relation to five land- scape categories. The survey found that the financial performance of the landscape categorized as "tall dense woodlands with scrub" was significantly poorer than for other landscape categories. The report has been used as a major reference for the recently completed Joint Parliamentary Committee Enquiry into the Western Division of New South Wales and has influenced a number of the economic recommendations in this report. This paper gives a brief summary of the financial results, a comparison of these results to those of other agricultural areas and the major policy recom- mendations made in the report.
Seasonal distribution of herbage growth from sandplain Mulga country, Charleville.
Authors: Silcock RG , Williams LM , Lehane KJ , Smith FT
Published: December 2005

Sod moisture may be adequate for rapid plant growth for prolonged periods at any time of year In the Charleville district. However, in pastures growing on mulga soils (acid, red earths), the majority of herbage is produced during the warm summer season (October 1 - March 31). Winter rams have to be well above average for herbage grown during these months to exceed 50% of annual production. The predominance of summer-growing (C4) grasses and absence of cool season grasses in the regional flora is the main reason for this pattern.

The density of mulga scrub has no effect on seasonal distribution of herbage production despite major differences in botanical composition. Increased tree density reduced herbage yields but increased the protein and mineral content of this fodder
The erosion cell - A geomorphic approach to landscape classification in range assessment.
Authors: Pickup G
Published: December 2005

Man) met hods for dealing with soil erosion in range condition assessment have an inadequate geomorphic basis because they only considertheimmediate eroded area. A morecompleteapproach is to divide an area into erosion cells. each of which consists of sediment productionzone,asedimenttransferzoneanda sink. The land surfaces developed in each of these areas are likely to have different ages, disturbance regimes, water supplies and nutrient status. and therefore different vegetation structures. Many of these erosion cells are natural but they can be enhanced by grazing pressure and climaticchange. Once erosion cells are recognised they may be used in range condition assessment to stratify monitoring sites and to develop indices of landscape stability and soil loss.
The effects of burning, fertilizing and clipping on populations of Aristida armata, Thyridolepis mitchelliana and Monachather paradoxa in a mulga woodland pasture.
Authors: Brown RF
Published: December 2005

The effects of burning, clipping, applying nitrogenous fertilizer, and protection from grazing on populations of three perennial grasses were monitored over four years in permanent quadrats in a mulga (Acacia aneura) woodland pasture near Charleville. Queensland. The grasses were the weedy invader Aristida armata (wiregrass), and two desirable species, Thyridolepis mitchelliana (mulga grass) and Monachather paradoxa (mulga oats). They comprised 70%, 16%, and 12%. respectively, of the pasture at the start of the experiment. Rainfall had a greater effect on plant numbers. especially of A. armata, than any treatment other than repeated clipping. The greatest mortality amongst A. armata plants occurred during a protracted dry period between March 1982 and April 1983 but the losses were more than compensated by mass germination during April 1983. The other two species responded similarly but less markedly. Repeated clipping caused attrition of all three species but failed to improve pasture composition. Pasture recovery after burning was slow and accompanied by a minor deterioration in pasture composition as measured by the proportion of A. armata plants. Burning caused greater mortality in A. armata plants than in the other two species but this was offset by greater A. armata seedling regeneration. Both initial survival and subsequent seedling recruitment were reduced by slashing a week prior to burning. When left ungrazed. T mitchelliana and M. paradoxa were more drought tolerant than A. armata and their relative numbers in the ungrazed plots increased over the four years of the experiment. Thus, protection from grazing offers the best prospect of improving pasture condition as none of the other treatments reduced A. armata numbers without adversely affecting those of T. mitchelliana and M. paradoxa.
Digestibility of Alpine Pasture on the Bogong High Plains of Victoria.
Authors: Gwaiseuk WR , van Rees H , Holmes JHG
Published: December 2005

The digestibility of the diet of cattle on the Bogong High Plains, in Victoria, was above 70% from the beginning of the grazing season in December 1982 until mid-March 1983, then fell to 63.5% at the end of the season in late March. Nitrogen content declined steadily from 1.60% to 0.99% in shrubland, 1.40% to 0.93% in grassland, 1.28% to 0.85% in mossbeds. The management implications are discussed.
Effect of short- and long-acting growth promotants on grazing beef cattle in south-west Queensland.
Authors: Clarke MR , Wythes JR
Published: December 2005

The effects of a single implantation of a short-acting (< 120 days) growth promotant - 36 mg zeranol (Ralgro) - were studied with one, two and three year old steers grazing Mitchell (Astrebla spp.) grasslands from March to June 1981 (107 days) in south-west Queensland. Implantation increased (P<0.05) mean final liveweight by 9.7, 18.1 and 11.0 kg for the one, two and three year old steers, respectively (control groups 317.6 kg, 432.3 kg and 519.1 kg). Tn a second experiment, the effects of a single implantation of a long-acting (400 days) growth promotant - 45 mg oestradiol 17 beta (Compudose 400) - were studied with steers grazing Channel pastures from October 1983 to April 1985 (540 days) in far south-west Queensland. Implantation increased (P<0.01) both mean final liveweight by 30.7 kg (control group 577.1 kg) and carcass weight by 14.2 kg (control 306.4 kg). Daily liveweight gains for implanted and control steers were 0.48 kg and 0.43 kg per day respectively @<0.01). There was no significant difference between the implanted and control steers in dressing percentage (52.7 cf. 53.2%) and fat ;hicknes.s at the P8 rump sGe (20.2 cf. 18.9 mm).
Strategic decisions in pastoral management.
Authors: Smith DMS , Foran BD
Published: December 2005

Pastoral managers face a bewildering array of management options while striving to remain viable. Many researchers and extension officers are forced to specialise, and "do good science" at the expense of working within a broader picture of practical station management. As a result their information and advice is often directed towards only part of a property's total management system. The development of new advisory tools, many of them using micro-computers, offer government officers and pastoral managers alike greater opportunities for effective interaction. We present the philosophy and structure of one tool, which has evolved with these developments, RANGEPACK HerdEcon, a dynamic herd or flock model linked to property cash flows. It can operate at a simple level initially, but it is able to mimic complex situations just as easily. Designed to accommodate sheep, cattle or mixed enterprises, it will enable a pastoral manager or an extension officer to develop management strategies for a particular property, which deal effectively with climatic variation, resultant animal production and subsequent cash flows. RANGEPACK HerdEcon will run on IBM compatible personal computers with at least 512k of RAM.
Blade ploughs as an alternative to tined rippers for rabbit warren destruction in semi-arid areas.
Authors: Hunt LP
Published: December 2005

A tractor-mounted blade plough was used to control rabbits in semi-arid South Australia by destroying their warrens. This implement was compared with a conventional two-tine ripper on the basis of effectiveness and cost. The blade plough was slightly less effective (overall mean 88% warrens destroyed) than the ripper (91% destroyed) three weeks after treatment but this difference was not significant. Warrens treated with the blade plough also had a slightly higher rate of reopening although the difference between treatments was not significant until 54 weeks after treatment. The blade plough was significantly faster in destroying warrens (mean 6.93 min cf. 9.88 min) despite frequent bogging of the tractor. The choice of a more suitable tractor should overcome this problem. Costs were similar but a small saving can be made by using a blade plough if a suitable tractor is already owned by the landholder. Including one follow-up treatment the cost of destruction per warren was $2.30 with the blade plough compared with $2.61 for the ripper. For properties where stock numbers are restricted, the return on an investment in rabbit control was estimated to be 13% per annum for the blade plough and 12% per annum for the ripper. Where stock numbers can be increased returns should be greater.
Rangeland restoration projects in western New South Wales.
Authors: Green DR
Published: December 2005

The semi-arid to arid Western Division of New South Wales has suffered significant levels of land degradation due to overstocking by domestic animals and rabbits. Three major forms of land degradation are identified, soil erosion, woody weed growth and pasture quality decline. Restoration techniques developed and applied by the New South Wales Soil Conservation Service are presented and discussed. The successful techniques presented are contour furrowing and waterponding for sheet eroded or scalded areas, fire and blade ploughing for woody weed control and grazing management to reverse pasture decline. The lack of knowledge on pasture species responses to grazing management stimuli is highlighted.
Quality and storage characteristics of the seeds of important native pasture species in South-West Queensland.
Authors: Silcock RG , Williams LM , Smith F
Published: December 2005

Seeds of native plants can be difficult to germinate reliably. In addition, the useful life of a carefully harvested seed lot needs to be known. This paper reports on the laboratory germination over eight years of seed of 27 native pasture species hand-harvested near Charleville after the 1972-73 summer and stored in a laboratory without special conditions. The legumes had prolonged hard-seededness and high viability. Forb species varied in their degree of hard-seededness and the level of initial dormancy, Most perennial grasses produced high quality seed which attained best germination between one and three years after harvest. The Andropogoneae had much poorer seed fill than most other species. Laboratory germination of annual and small seeded grasses was often low, even after scarification. Thus, the use of freshly harvested or old, untested seed of native rangeland species in - research programmes is very unwise.
Grazing Management Strategies for Reseeded Rangelands in the East Kimberley Region of Western Australia.
Authors: Hacker RB , Tunbridge SB
Published: December 2005

Grazing management strategies involving continuous grazing, wet season rest, dry season rest and a range of stocking rates of steers were evaluated on reseeded rangeland at Ord Regeneration Research Station by the use of temporary exclosures within continuously grazed paddocks. The rangeland is a patchwork of plant communities in various stages of regeneration.

Under continuous grazing, liveweight gain in three of the four years of the trial was more closely related to botanical differences between paddocks than to stocking rate although all paddocks were confined to the one land unit. Animals generally selected those parts of the pasture where regeneration of perennial grasses was least advanced and the vegetation was characterized by short annual and semi-perennial species. Differences in the yield of these species between paddocks accounted for much of the variation in liveweight gain. Perennial species contributed most to animal production when seasonal conditions were poor.

Over the study as a whole, year-in-year-out stocking rate was much more important than management system (proportion of wet season grazing) in determining vegetation changes. Nevertheless, selective grazing of the short grass patches will prevent the use of a continuous grazing strategy in these pastures. However, continued regeneration should be feasible under a tactical management system in which grazing is managed to ensure that a minimum level of cover is maintained on the short grass phase and that the end of dry season utilization level for the key perennial species does not exceed an average (over years) of about 30 per cent.
Effect of a Single Clipping on the Seed Production Response of Astrebla Spp.
Authors: Orr DM , Evenson CJ
Published: December 2005

A field study was conducted to examine the process by which grazing promotes seed production in Astrebla spp. (predominantly A, lappacea). To simulate grazing, plots within an area of lightly grazed Astrebla grasslands were clipped once, at a range of severities, at the end of the dry season. Grazing pressures ranging from 10% to 90% utilization of A. lappacea were simulated by the clipping treatments.

Increasing the severity of clipping gave increased seed production, by increasing the density of inflorescences borne on secondary tillers. In contrast, inflorescence density on main tillers was unaffected by clipping. We concluded that grazing promotes seed production in Astrebla spp. through its effect on inflorescence density on secondary tillers.
An Evaluation of Cover Type as a Predictor of Soil Surface Roughness in a Semi-Arid Grassland.
Authors: Eldridge DJ
Published: December 2005

Sites dominated by perennial grasses were significantly rougher than sites dominated by ephemerals and the the character of the surface cover did not explain the variation in surface roughness at most sites. Rougher sites dominated by grasses have a greater water storage capacity, enhanced and are probably more biologically active than sites dominated by ephemerals.
The influence of kangaroos and forage on sheep productivity in the semi-arid woodlands.
Authors: Wilson AD
Published: December 2005

Problems of pasture degradation and competition from kangaroos in the semi-arid woodlands were investigated in a grazing trial conducted in western New South Wales. The trial area of 200 ha was subdivided into 12 paddocks, varying in size from 7.5 to 30 ha and grazed with matched groups of six merino hoggetts, with and without a similar number of western grey kangaroos. Stocking rates were 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8 sheep per hectare and 0.2, 0.27, 0.33, 0.4, 0.47 and 0.53 sheep per hectare, with an equal number of western grey kangaroos. Wool growth and weight gain of the sheep, and the yield of forage species and components, were recorded quarterly over a three year period. Rainfall received over these years was close to the 30, 90 and 50 percentile levels respectively. The results were analysed by regression modelling. Both wool growth and sheep weight gain were reduced by increasing stocking rates of sheep or kangaroos, except when forage was abundant. The relative effect of kangaroo grazing was greatest in the year of lowest rainfall, with an equivalence of one sheep: 0.6 kangaroo of equal weight. Forage biomass declined as stocking rates increased with kangaroos having the equivalent effect of 0.75 sheep on a weight for weight basis. More than 80 per cent of the variation in clean fleece weight (CFW, kg/year) and annual sheep weight gain (WG, kg/year) was explained by the average yield of green herbage leaf (GL, kgtha) in the expressions and CFW = 1.30 + 0.72 In GL WG = 5.6 In GL These results show that sheep productivity can be increased by controlling kangaroo numbers in the drier years. They also indicate that productivity can be raised by increasing the abundance of palatable perennial species, which maintain green leaf during periods of moderate and low rainfall.
Forage utilization by sheep and kangaroos in a semi-arid woodland
Authors: Wilson AD
Published: December 2005

The utilization of forage species by sheep and western grey kangaroos, and their contribution to the diets of those animals, were determined in a mulga (Acacia aneura) woodland in western New South Wales. Utilization was determined from measurements of forage yield, on pastures that were grazed by either sheep, sheep and kangaroos together or kangaroos, at a range of stocking rates. The sheep and kangaroos had similar preferences for the major grasses, with high utilization of species such as Monachather paradoxa and low utilization of the more fibrous species such as Eragrostis eriopoda. At times of forage abundance, annual and perennial forbs were a major component of sheep diet but a relatively minor component of kangaroo diet. Differences in species preference thus arose mainly in species that were uncommon or of seasonal occurrence. The overall diets of sheep and kangaroos were similar, with a year-round predominance of the same group of perennial grasses such as Thyridolepis mitchelliana. In the treatment where sheep and kangaroos grazed together, kangaroos had access to areas exclosed from sheep and their use of these areas increased with increase in stocking rate. Thus the exclosures received a similar grazing pressure by kangaroos alone, to that of the surrounding paddocks grazed by a mixture of sheep and kangaroos. It is concluded that there is direct competition between sheep and kangaroos for the main forage species. There are also long-term effects of high kangaroo populations on sheep production because the movement of kangaroos to rested paddocks negates any pasture management practice that requires periodic resting of pastures from grazing.
Trends in the recruitment of Astrebla spp. in relation to seasonal rainfall.
Authors: Orr DM
Published: December 2005

Differences in both the occurrence and size of the recruitment of Astrebla spp. (mainly A. lappacea) in Astrebla grassland have been reported from three geographically different locations. The studies reported in this paper were undertaken to develop an understanding of the factors affecting the recruitment of Astrebla spp. at Cunnamulla and Julia Creek at the southern and northern extremities of Astrebla grasslands in Queensland. The germinable seed bank of Astrebla spp. at Cunnamulla in October 1981 was 250 seeds/m2 compared with only 60 seeds/m2 at Julia Creek while the germinable seed bank of Iseilema spp. was 3020 seeds/m2 at Julia Creek compared with < 1 seed/m2 at Cunnamulla. Grazing had no effect on the germinable seed banks of Astrebla spp. but grazing at Julia Creek increased the germinable seed bank of Iseilema spp. Recruitment of Astrebla spp. was recorded at both locations. At Cunnamulla, an unusually large recruitment of 15.0 plants/m2 of Astrebla spp. was recorded in July 1983 following a severe drought in the previous summer. At Julia Creek, a density of 1.4 seedlings/m2 of Astrebla spp. was measured in 1984 and this may have been the first recorded recruitment of Astrebla spp. in the ten year history of the permanent quadrats. Recruitment at Julia Creek was associated with a low density (< 3 plants/m2) of Iseilema spp. I conclude that the seasonal pattern of rainfall, as it influences the size and composition of the soil seed bank, is the major factor affecting recruitment of Astrebla spp. An integrated understanding of Astrebla spp. persistence across its range is presented.
Patterns of waterbird use in wetlands of the Paroo, A river system of inland Australia.
Authors: Maher MT , Braithwaite LW
Published: December 2005

The significance of inland wetlands to Australian waterbirds has been overlooked until recently. One important area identified from regular aerial survey centres on the Paroo River in north-western New South Wales. Between April 1983 and December 1985, a period covering a major flood, waterbird populations were estimated on five wetland systems associated with the Paroo during 14 trips. Fifty- three waterbird species were recorded with the anatids, Anas gibberifrons and Malacorhynchus membranaceus, accounting for 75 per cent of total estimated populations. Most breeding events were observed in those wetlands dominated by Muehlenbeckia florulenta (lignum). Breeding accounted for shifts in waterbird populations between wetland systems. A model of waterbird usage of the five wetland systems in relation to a complete flood event is described. The importance for waterbird conservation of wetlands used for breeding and maintenance of populations between flood events, and threats to the integrity of these wetlands are discussed.
Mound Springs: South Australian Conservation Initiatives.
Authors: Harris CR
Published: December 2005

The mound springs of inland Australia are of outstanding scientific and cultural importance. Natural outlets for the waters of the Great Artesian Basin, they are found mostly on or near its margins. The most numerous and active are in the far north of South Australia. Parts of westem Queensland still have active springs, but almost all in north-westem New South Wales are now extinct, presumably because of aquifer draw-down in the wake of bore sinking. As permanent sources of potable water in a desert environment they have been a focus for human activity over many years. Aboriginal occupation has been documented to at least 5000 years BP and almost all the springs are rich in archaeological material and mythological associations. Since European settlement they have been of strategic importance in exploration and in the location of pastoral stations, the Overland Telegraph and the old Ghan narrow gauge railway from Marree to Oodnadatta. Biologically, they represent unusually specialised aquatic habitats, the discontinuity being analogous to islands and the isolation just as great for species with limited dispersal abilities. The result is an assemblage of plants and animals of evolutionary, biogeographic and ecological interest, with many endemic and relict species. Heavily degraded by aquifer draw-down and over a century of pastoralism, the springs were given little attention until relatively recently. In the past decade two key areas have been acquired for the national parks system and ten important springs on pastoral country outside of the parks have been fenced. Important research has also been carried out, with a particular focus on the endemic elements of the invertebrate fauna. These are positive achievements, but the remoteness of the localities where the springs occur presents a continuing difficulty for on-going conservation and management programs.
Diet of red foxes (Vulpes vulpes) in South-west New South Wales, with relevance to lamb predation.
Authors: Lugton IW
Published: December 2005

The diets of 212 foxes (Vulpes vulpes) in the far south-west of New South Wales were determined between 1985 and 1989 and compared with other Australian studies. Mammalian remains, at an overall occurrence of 99.1%, formed the basis of the diet during the autumn and winter months. The most frequently occurring mammals were rabbits (Oryctolagus cuniculus) (34.9%), sheep (Ovis aries) (30.7%) and macropods (Macropus spp.) (20.3%). Insects occurred in 31.1% of stomachs and formed a substantial proportion of the diet. Fresh newborn lamb was identified in only 3.8% of all stomachs, but evidence of lamb consumption was 10 times greater (35.2%) from foxes collected near lambing flocks. Other studies around lambing flocks have also shown a high occurrence of fresh lamb in fox stomachs and there is circumstantial evidence that predation of lambs by foxes can be common. It was concluded that lamb predation is likely to be severe where the fox population density is high, where older foxes predominate, and where alternative preferred foods are scarce. More research is required to confirm these observations.
A Glasshouse Study of Competition Between Astrebla Lappacea (Curly Mitchell Grass) and Two Associated Species.
Authors: Orr DM , Evenson CJ
Published: December 2005

Recruitment of Astrebla spp. (Mitchell grass) may be restricted by high densities of the summer, annual grass Iseilema spp. (Flinders grass). This paper reports a glasshouse study undertaken to assess the competitive ability of A. lappacea in relation to that of Iseilema spp. and also that of the summer, annual forb Hibiscus trionum (Bladder ketmia). Astrebla lappacea was equally competitive with H. trionum but more competitive than Iseilema sp. However, it is concluded that, in the field, the recruitment of Astrebla spp, may be restricted by high densities of Iseilema spp. It is unlikely that the density of summer forb species are sufficient to restrict Astrebla spp.
Some Effects of Fire on the Survival of Sifton Bush (Cassinia Arcuata R.br.).
Authors: Semple WS , Koen TB
Published: December 2005

A number of buming procedures were investigated over three seasons for their potential to kill individual sifton bushes (Cassinia arcuata). The methods compared were an unburnt control, a foliage-only bum and a factorial arrangement of two basal buming energies (20 and 56 kW) for three durations (3, 6 and 9 seconds). Burning shrub bases generally killed more shrubs than burning the foliage. This was attributed to thin bark and lack of below-ground shoot meristems. Within the range of intensities used (195 kW/m and 545 kW/m), duration of the basal bum had more influence than intensity in killing shrubs. Small shrubs (<800 mrn) were generally more easily killed by buming. Shrubs were more susceptible to all burning treatments in spring 1990. Subsequent dry conditions were suggested as a probable reason for this. The results and observations following fires in stands of sifton bush indicate that it is a seed regenerator following fire. Unless some means of controlling seedlings is available, caution should be exercised when using fire to control this species.
Distribution and Relative Abundance of Feral Goats in the Rangelands of Eastern Australia.
Authors: Southwell C , Weaver K , Sheppard N , Morris P
Published: December 2005

An aerial survey of 966,000 km2 of the arid/semi-arid rangelands of Queensland and New South Wales in the winter of 1992 indicated a minimum feral goat population of almost 1 million animals (density 0.97�0.12/km2). Observed density (f standard error) was higher in New South Wales (1.51�0.23/km2) than in Queensland (0.47�0.09/km2).
Managing Sheep for Optimum Productivity in Astrebla Pastures in North-West Queensland.
Authors: Cobon DH , Connelly PT , Bailey JV , Newman PA
Published: December 2005

A yearly management program for sheep in north-west Queensland has increased lambing percentage by > 20% compared with the district average. Greasy wool production of ewes over 4 years (1988-91) averaged 4.3 kg and wethers over 2 years (1990-91) averaged 5.7 kg. Managing sheep using this program increased wool production of the flock compared with the district average. The economic advantages of running breeding ewes or wethers was influenced by wool and sheep markets. During low wool prices ($2.82/kg net selling costs, 1990; $2.44/kg net selling costs, 1991) it was estimated that a 65% lamb weaning rate was needed for returns from the ewe and wether flock to be equal. Gross margins ($/DSE) for the ewe flock were 21.80, 17.07, 8.53 and 5.42 in years 1988, 1989, 1990, 1991 respectively and 5.82 and 5.01 for wethers in 1990 and 1991 respectively. Gross margin ($/DSE) of combined ewe and wether enterprises on properties representing the district, averaged 16.50, 14.20, 8.00 and 5.00 in years 1988, 1989, 1990 and 1991 respectively. The management program implemented at Toorak generated higher gross margins than the district average particularly during the years of higher wool prices.
Recolonisation by Rabbits (Oryctolagus Cuniculus) After Warren Ripping or Warren Fumigation.
Authors: Parer I , Milkovits G
Published: December 2005

Attempts were made to exterminate rabbits at six separate sites; recolonisation was measured over the following two years. Three sites were treated by repeated warren ripping and three by repeated warren fumigation. At all sites the warren treatments were supplemented by shooting and dogging. Two years after treatment, the density of rabbits was 56% of the original density on fumigated sites and 50% on ripped sites. In the first year after treatment, reopened warrens were found more commonly than newly dug warrens; in the second year there were more new warrens than reopened ones. More of the treated warrens reopened on fumigated sites (40%) than on ripped sites (21%). For individual warrens, the number of entrances at treatment and the distance a warren was from untreated rabbit populations were the main factors influencing the probability of reopening. Population density on the periphery of the sites was the main factor influencing the rate of recolonisation of the sites and group control schemes are recommended to minimise recolonisation after control.
Estimating Safe Carrying Capacities of Extensive Cattle-Grazing Properties Within Tropical, Semi-Arid Woodlands of North-Eastern Australia.
Authors: Scanlan JC , Mckeon GM , Day KA , Mott JJ , Hinton AW
Published: December 2005

A methodology is presented to estimate the safe carrying capacity of properties in extensive cattle- grazing regions within tropical, semi-arid woodlands of north-eastern Australia. Carrying capacities for 45 properties were calculated from resource information collected from the properties. These calculated carrying capacities were then compared with graziers' estimates and with Queensland Department of Lands' ratings. The rated carrying capacities were not correlated with either the calculated values or the graziers' estimates, and in general were much lower than both other values. The graziers' estimates and the calculated values were highly correlated with a slope not significantly different from 1 (p>0.1). This methodology could form the basis of a review of rated carrying capacities on an objective basis. Refinements would be necessary to improve the determination of individual cases with particular emphasis on spatial variability of resource use and fine scale variability in soil fertility and tree and shrub density.
Comparison of Wheel Point and Point Frame Methods for Plant Cover Measurement of Semiarid and Arid Rangeland Vegetation of New South Wales.
Authors: Arzani H , King GW
Published: December 2005

Ground cover is frequently estimated in rangeland monitoring and it is an important intermediate measurement between biomass estimation and satellite imagery. As a preliminary phase in a longer term program, wheel point and point frame methods were used to measure vegetation cover on four permanent Soil Conservation Service transects at each of four land systems in western New South Wales, at Nyngan (410 mm average annual rainfall), at Cobar (364 mm average annual rainfall) and two at Fowlers Gap (200 mm average annual rainfall) north of Broken Hill. The majority of this work used 400 wheel point hits per transect and 100 point quadrats sub sampled 9 - 13 times along each of four transects. There was no statistically significant difference between these techniques for total foliage cover over a combined analysis of all sites under pre-drought conditions, and for pre-drought and post-drought at Cobar. However, there was a 10% difference estimated between the techniques for total foliage cover at Nyngan when it was analysed in isolation. There were no consistent differences in technique for cover estimation for more than 40 plant species including annual grasses and herbs, perennial grasses and saltbushes. Significant differences between techniques were found for Medicago sp. and Thyridolepis mitchelliana on one occasion. We believe that these differences were due to the problems of finding small plants in tall grass and identifying heavily grazed grasses during drought conditions at Cobar and, in the latter case, this was also associated with a significantly greater estimate of mean cover for all grasses and thus total foliage cover. Although there was generally no statistical difference between techniques our observations suggest that the point frame tends to give lower estimates of cover than the wheel point in the situations measured. This may be associated with the circumference of the marker pins on the wheel point or perhaps observer error but as this effect appeared to be more noticeable with grasses we suspect that the former is most likely. The wheel point is less time consuming, more convenient and simpler to use than the point frame, and will readily accommodate most temporal and spatial variation in sampling requirements in similar land forms in western New South Wales.
Perceptions of Beef Cattle Producers and Scientists Relating to Sustainable Land Use Issues and Their Implications for Technology Transfer.
Authors: Macleod ND , Taylor JA
Published: December 2005

Selected results are presented for two sub-groups drawn from a postal survey of perceptions of sustainable grazing management issues in the beef cattle-grazed rangelands of Queensland. The sub- groups include beef cattle producers and research scientists, both of which are key stakeholders for effective technology transfer from R&D projects that address sustainable grazing land management problems. Some important similarities and differences are highlighted between the sub-groups which are believed potentially to impact on the design and operation of R&D projects, the principal aim of which is to improve sustainable management practices. These relate to land use objectives and perceived sustainability of current grazing practices, and to the feasibility of rectifying present land degradation problems. Similarities are evident in the high proportions of both groups which do not believe that present practices are sustainable and with the same perceptions about the principal causes of grazing land degradation and the feasibility of rectifying present land degradation problems. Major differences relate to the perceived management objectives of beef producers, the scale at which land degradation problems occur, and the key sources of information or knowledge on which sustainable grazing systems might be developed.
Natural Regeneration of Ground Storey Vegetation in a Semi-Arid Woodland Following Mechanical Disturbance and Burning. 2. Response of Individual Species.
Authors: Walker PJ , Koen TB , Gittins R
Published: December 2005

A study was made over a period of 12 years of the natural regeneration of vegetation along a corridor cleared for the construction of a natural gas pipeline in a semi-arid woodland in central-western New South Wales. Total cover, proportion of grasses, and species composition were assessed on the infilled trench and areas from which topsoil had been bladed, as well as on adjacent undisturbed areas or areas burned by a wildfire. All areas were grazed continuously by sheep under normal station management. The effects of mechanical disturbance and of burning on individual species were measured in terms of species dominance and occurrence. Some insight was also gained in to the successional process on bared sites and in to the effects of the timing of seasonal rainfall on species composition. Of the 75 major species recorded, 15 were found to have greater occurrence on trenched sites, 46 decreased in occurrence and 14 showed no clear trend. Perennial grasses and small annual plants were the main decreasers, whilst Medicago spp., Erodium crinitum, Hordeum leporinum and certain 'weedy' annuals were the main increasers. Some of the early colonisers lasted only a few years or even less in any quantity, thereafter to be replaced by other increasers. Burning had little effect on the long-term occurrence of Stipa variabilis, Wahlenbergia spp., Helipterum spp., Calotis cuneifolia and some minor species. Eragrostis lacunaria appeared to decrease, while several annual plants were more common on burned areas.
Grazing Management: Technology for Sustaining Rangeland Ecosystems?
Authors: Heitschmidt RK , Walker JW
Published: December 2005

This paper examines the ecological, economic, and social aspects of grazing management technology as it relates to sustaining rangeland ecosystems. We adopt FAO's definition of sustainable agriculture, that is, 'The management and conservation of the resource base and the orientation of technological and institutional changes in such a manner as to insure the attainment and continued satisfaction of human needs for present and future generations. Such sustainable development is environmentally non-degrading, technically appropriate, economically viable and socially acceptable." We explore the ecological aspects of grazing management as they relate to the need to balance solar energy capture and harvest efficiency so as to maximize productivity on a sustained basis. The long- term success or failure of all grazing strategies hinges around management's ability to control the frequency and severity of defoliation of individual plants over time and space. This is a particularly formidable challenge in rangeland environments because of high levels of environmental uncertainty. We then focus attention on the social aspects of grazing management. Grazing management is a social process by virtue of its human component and the major social dilemma encountered in grazed agroecosystems centers around the impacts that ever-increasing human desires have on rangeland resources. We examine the role of ecological economics and the impact of varying human value systems on management of rangeland resources. The fundamental problem encountered in the management of natural resources such as rangeland ecosystems is absence of perfect ecological knowledge. We conclude that the major social dilemma of grazing management stems largely from two phenomena: 1) supply side management tactics designed to meet ever increasing human demands; and 2) potential failure to accurately factor long-term ecological costs into present day value systems. As such, we conclude that current grazing management technology necessarily requires moderate rates of stocking be employed to insure rangeland agriculture (i.e. grazing) is ecologically sound, economically viable, and socially acceptable.
Objective `Safe' Grazing Capacities for South-West Queensland Australia: Model Application and Evaluation.
Authors: Johnston PW , Tannock PR , Beale IF
Published: December 2005

This paper describes the employment of two experienced graziers as consultants to apply and evaluate a model for calculating 'safe' long-term grazing capacities of individual properties. The model was based on ecological principles and entailed estimates of average annual forage grown (kglha) on the different land systems on each property and the calculation of the number of livestock (dry sheep equivalents, DSE) required to 'safely' utilise this forage. The grazier consultants applied and evaluated the 'safe' grazing capacity model on 20 properties of their choosing. For evaluation, model results were compared with; (a) the Department of Lands rated carrying capacities for those properties and (b) the grazing capacity assessed independently by the owners of those properties. For the 20 properties, the average 'safe' grazing capacity calculated by the model (21.0 DSE/kmZ) was 8% lighter than the average of the owner assessed capacities (22.7 DSE/kmZ), which in tum was 37% lighter than the average of the pre-1989 Department of Lands rated carrying capacity (31.0 DSE/kmZ). The grazing land management and administrative implications of these results and the role graziers played as consultants are discussed.
Event-Driven or Continuous; Which Is the Better Model for Managers?
Authors: Watson IW , Burnside DG , Holm AM
Published: December 2005

Over the past ten years or so, discussion of vegetation change in rangeland science has emphasised event- driven or episodic processes, occurring on timescales measured in decades or longer. Management recommendations arising from this literature have stressed that management must also be event-driven. This paper cautions against the uncritical acceptance of such a world view into management philosophies. We conclude that for management purposes, appropriate models of change in rangeland systems should include a balance between the effects of infrequent, unpredictable events and the effects of more continuous processes, measured in timescales of years or less. This may involve explicit recognition of multiple timescales in a hierarchical model system. We arrive at these conclusions from a number of perspectives. Firstly, a substantial proportion of total demographic change in shrub populations occurs between events. Secondly, managers are best able to devise appropriate management strategies by a process of adaptive management. This can only be successful if the adaptive cycles have a short return time. Thirdly, it is important that managers think of change as being continuous. Mental models held by managers must acknowledge the value of continuous change. This provides the best opportunity for acquiring knowledge through experience and helps prevent management inertia when faced with an event outside previous experience. Finally, management can take best advantage of a given event by 'conditioning' the resource. This can be thought of as managing within states, say by building up a seedbank, and provides the opportunity to alter the probability of a given event occurring.
Factors Associated With Density of Mitchell Grass Pastures in North-Western New South Wales.
Authors: Bowman AM , Munnich DJ , Chan KY , Brockwell J
Published: December 2005

Thirty-eight paddocks on 23 properties in the Walgett Shire of north-westem New South Wales were surveyed in April and May 1993 to identify factors that affected Mitchell grass (Astrebla lappacea) plant density. Low densities of Mitchell grass were associated with the occurrence of at least one flood in the last 20 years. Soils from paddocks described by landholders as in poor condition, and where Mitchell grass density was low, were more alkaline and had significantly higher electrical conductivity than soils from paddocks described as in good condition, and where Mitchell grass density was high. Paddocks in poor condition had higher organic carbon and mineralisable nitrogen levels and higher soil populations of Rhizobium meliloti. These latter characteristics were attributed to these pastures having a high component of annual species, including Medicago species, which returned substantial amounts of carbon and nitrogen to the soil. Where Mitchell grass density was moderate, other palatable species were common and biodiversity was high. However, in paddocks with the lowest densities of Mitchell grass, both annual species and unpalatable perennials were common. Low basal diameter of Mitchell grass plants and low Mitchell grass density, were associated with higher grazing pressure. The data suggested that the Mitchell grass ecosystem in north-westem New South Wales is prone to deterioration on the more alkaline and saline soils and where inundation by flooding or waterlogging is common.
Effect of Seedbed on Emergence and Establishment From Surface Sown and Direct Drilled Seed of Eucalyptus Spp. And Dodonaea Viscosa.
Authors: Semple WS , Koen TB
Published: December 2005

In some areas the increase of woody plants is a problem whereas in others, the lack of regeneration is viewed with a similar degree of concern. The experiments described in this paper were an attempt to further understand factors affecting regeneration of woody plants. The effect of seedbed on the emergence and survival of hopbush (Dodonaea viscosa ssp. angustissima) and on several species of Eucalyptus was evaluated at two sites in the Central West of New South Wales. Seed was sown in two springs, two summers and two autumns from 1990 to 1992 and seedlings monitored for 12 months after sowing. Seedbeds compared were prepared by cultivation, scalping, burning, applying herbicide (glyphosate) and mowinglgrazing (control). Following failure of surface sowing in spring 1990 and summer 1990191 due to poor seasonal conditions, all subsequent experiments included direct drilled controls. Emergents were recorded in most treatments in the four succeeding seasons but hopbush and eucalypts responded differently to treatments. Numbers of hopbush emergents and seedlings after 12 months were consistently higher following direct drilling into scalped seedbeds. In contrast, the maximum number of eucalypt emergents was not consistently associated with any seedbed type, though emergence was generally higher following direct drilling. However, higher numbers of eucalypt seedlings were present in scalped plots after 12 months. It was concluded that weed control following emergence was the main effect of seedbed preparation on the number of eucalypt seedlings present after 12 months. Though this also applied to hopbush. seedbeds which provided the opportunity of seed burial enhanced emergence. This was believed to be due to the breaking of seed dormancy.