bluuebunny/crossref_metadata_2025 huggingface dataset:
The Stereochemistry of 16α,28-Isopropylidenedioxyolean-12-en-3β-ol and the Olean-13(18)-ene Isomer
Authors: Hambley Trevor W. , Lewis Keith G. , Tucker David J. , Turner Peter
Published: December 2005

The stereochemistry of 16α,28-isopropylidenedioxyolean-12-en-3β-ol
(1b) and its Δ13(18) isomer (2b) have been
determined on the basis of n.m.r. studies and by X-ray crystallographic
examination.
Cyclic Voltammetry and Chronoamperometry of 1-Methylxanthine: Evidence for an Unstable para-Quinonoid Diimine Intermediate
Authors: Goyal Rajendra N. , Kumar Neeraj
Published: December 2005

The electrooxidation of the adenosine antagonist 1-methylxanthine has been
studied in the pH range 2·5–10·7 at the pyrolytic graphite
electrode. The initial 4e, 4H+ oxidation step leads to
the formation of an unstable diimine, for which the half-life was found to be
1·8 s by chronoamperometry. The diimine is readily attacked by water to
give a carbinolamine which decomposes in a pseudo first-order reaction to
give, as the major products, 1-methylalloxan at pH 3·0 and
5-hydroxy-5-(methylcarbamoyl)hydantoin at pH 7·0. The oxidation
products were identified. The diimine can also be reversibly reduced to the
2,6,8-trioxopurine anion derivative which is also formed by the 2e,
2H+ reduction of the carbinolamine. A tentative
mechanism for the formation of the products has also been suggested.
An Adventitious Synthesis of 2,2′-Dipyrryl Disulfides
Authors: Adhikari Raju , Jones Dionne , Liepa Andris J. , Mackay Maureen F.
Published: December 2005

Condensation of 1,2-diketones and a cyanothioacetamide gave hydroxy
thiolactams which failed to give the expected 3-cyano methylene thiolactams on
dehydration. Disulfides and a thiosulfonate were obtained from the
dehydrations. A possible mechanism for their formation is proposed. The
crystal structure of the disulfide
4,4′,5,5′-tetramethyl-1,1′-diphenyl-2,2′-disulfanediyldi-1H-pyrrole-3-carbonitrile
(9) has been determined by X-ray diffraction.
2,4-Bis[4-(dihexadecylamino)-2-hydroxyphenyl]-squaraine: Second-Harmonic Generation from Langmuir - Blodgett Monolayers of a Centro-symmetric Dye in which the Chromophores are Isolated from the Substrate
Authors: Ashwell Geoffrey J. , Williamson Patricia C. , Bahra Gurmit S. , Brown Christopher R.
Published: December 2005

2,4-Bis[4-(dihexadecylamino)-2-hydroxyphenyl]squaraine is vertically
oriented in the Langmuir–Blodgett film and the chromophore layer is
separated from the glass substrate by the hydrophobic dihexadecylamino groups.
The Langmuir–Blodgett monolayer exhibits moderately strong
second-harmonic generation (SHG) with an effective susceptibility of
c. 10 pm V-1 at 1064 nm and an
intensity, relative to the mean SHG from films of the extensively studied
hemicyanine dye
(E)-4-[2-(4-dimethylaminophenyl)ethenyl]-N-docosylpyridinium
bromide, of c. 0·3. The SHG cannot arise from the
polarization of the dye by the underlying substrate because the conjugated
donor-(acceptor)-donor moiety is separated by a 2 nm thick hydrophobic
barrier. Instead, the non-linear optical behaviour is attributed to a
non-centrosymmetric aggregate structure.
Reflections on Aluminium: Some Thoughts on the Mesospheric Processing of Ablated Meteoric Al+
Authors: Petrie Simon
Published: December 2005

Environmental Context.As the second most abundant main-group metal, Al is a prominent constituent of meteors. Other metal-containing products of meteoric infall have been implicated in noctilucent cloud nucleation and polar stratospheric cloud formation. Aluminium is also the principal metallic component of the space debris in low Earth orbit. Re-entry of this debris is an anthropogenic route to neutral and ionized Al atoms in the upper atmosphere, the consequences of which are as yet unknown. The calculations reported here suggest that natural mechanisms exist for the processing of Al+ to yield neutral Al-containing structures that are likely to be highly reactive with trace upper-atmosphere constituents.
Abstract.Quantum-chemical calculations, at the CP-dG2thaw level of theory, are used to characterize several novel Al-containing molecular and cluster ions that are likely to participate in the chemistry of Al+ resulting from meteoric ablation in the upper atmosphere. The calculations suggest that two overall processes may be dominant in aluminium’s ion chemistry in the mesosphere/lower thermosphere (MLT) region. The first of these processes is an efficient cycle (Al+ → AlN2+ → AlO+ → Al+), with addition of N2 to Al+ the apparent rate-determining step on the overall cycle, and with weak competition from neutralization processes. The second possible process involves conversion of Al+ to the species HOAlOH+, by (we propose) reaction with H2O and O (3P) respectively. Although water vapour is only a trace species within the mesosphere, production of HOAlOH+ appears pivotal: This molecular ion is intrinsically stable against substitution or abstraction involving other mesospheric species, but is highly activated towards further addition of N2, CO2 and H2O. We propose that, once formed, HOAlOH+ is rapidly consumed through condensation reactions, producing larger cluster ions whose eventual neutralization through dissociative recombination will most probably yield hydrated AlOn structures. These Al-containing neutrals may act as nucleation sites for noctilucent and polar stratospheric clouds.
Post-early cretaceous landform evolution along the western margin of the Bancannia trough, western NSW.
Authors: Gibson DL
Published: December 2005

Previously undated post-Devonian sediments outcropping north of Fowlers Gap station near the western margin of the Bancannia Trough are shown by plant macro- and microfossil determinations to be of Early Cretaceous (most likely Neocomian and/or Aptian) age, and thus part of the Eromanga Basin. They are assigned to the previously defined Teleplione Creek Formation. Study of the structural configuration of this unit and the unconformably underlying Devonian rocks suggests that the gross landscape architecture of the area results from post-Early Cretaceous monoclinal folding along blind faults at the western margin of the trough, combined with the effects of differential erosion. This study shows that. while landscape evolution in the area has been dynamic, the major changes that have occurred are on a geological rather than human timescale.
Key words: geology, landscape evolution, Eromanga Basin, folding
Long-term change in the economic productivity of four major pasture categories on the south-eastern Tablelands of New South Wales
Authors: Vere D. T. , Jones R. E. , Campbell M. H.
Published: December 2005

The perception of change or decline in the productivity of temperate pastures in south-eastern Australia is an important concern to livestock producers and pasture scientists. Much of this concern relates to reductions in the proportions of desirable species in the composition of pasture systems as a result of increased soil and weed problems. The purpose of this paper is to investigate trends in the long-term economic productivity of four categories of temperate pastures (all introduced pastures, introduced perennial grasses, introduced legumes and all native pastures) on the central and southern tablelands of New South Wales. The results provide evidence of economic productivity decline in the all introduced pastures category in relation to sheep production, but this has been due to productivity decline in the dominant legume component of the introduced pastures. In contrast, there has been strong growth in the economic productivity of the introduced perennial grass pastures. Abnormally high beef cattle numbers in the mid-1970s appear to have created an illusion of high productivity and subsequent decline in all introduced pastures. In contrast, the economic productivity of the native pastures which are the bulk of the region's grazing areas, has fallen substantially.
Growth rate and effect of sheep browsing on young eucalypts in an anthropogenic Themeda grassland
Authors: Semple W. S. , Koen T. B.
Published: December 2005

This paper reports the fate of both pre-existing ('lignotuberous') and newly-emerged eucalypt seedlings in an anthropogenic Themeda australis grassland on the Central Tablelands of NSW under varying grazing regimes. Compared to reported growth rates on farms elsewhere, the rate of height increase was low for both unbrowsed pre-existing and new seedlings: 16.7 (� 2.5) and 16.6 (� 0.3) cm/a respectively. Heights remained unchanged or declined during the cooler months. Most of the new seedlings were not above sheep grazing height 4.5 years after their presumed time of emergence.
Portions of the seedling population were exposed to a short period of high intensity sheep grazing in spring 1996 and/or autumn 1997. The effect of crash-grazing was more pronounced in spring, when over 90% of available seedlings were browsed, than in autumn when only about half of the available population was browsed. Mortality of new seedlings was higher following grazing in spring than in autumn. The finding that seedlings were not selectively browsed in autumn offers a means of conserving eucalypt regeneration while at the same time deriving some production from pastures. Reasons for different grazing effects in autumn and spring are unknown but could be related to differences between the pastures and/or between eucalypt seedlings on the two occasions.
Rights to the rangelands: European contests of possession in the early 20th century
Authors: Quinn Michael
Published: December 2005

Resolving competition over rights to the resources of Australia's rangelands is an issue of national prominence. In the early 20th century, European competition over the rangelands reflected the idea that the land needed to be used 'productively' for its occupation to be legitimate, and the idea that the rangelands were the 'public estate'. These perspectives about rights to the rangelands expose roots of today's conflicts. A central theme of 19th century Australian history has been conflict between squatters and colonial governments. By the beginning of the 20th century, occupation of the rangelands had been mostly legitimised through leases and licenses. Governments have continued to use leases to influence access and the use of the rangelands.
The 20th century saw conflict continue over rights to the rangelands. Closer settlement, an expression of this conflict, sometimes led to land use that was disastrous for the land and those who used it. The career of the pastoralist Sidney Kidman illustrates the conflicts between the landed and landless, and the inseparability of 'productive' and 'legitimate' land use. The beginning of the 20th century also saw growing knowledge about the environmental impacts of rangeland pastoralism. The rights of lessees and governments were widely renegotiated, in the example of New South Wales, in all attempt to make land use better reflect this new knowledge and to protect the 'public estate'.
Today, the history of the rangelands is used by different groups to justify perceived rights to its resources — these rights are legitimised culturally as well by the narrower prescriptions of the law. As social values change, different interests in the rangelands need to be accommodated. A better awareness of past ideas about the rights to the rangelands may in a small way help reconcile these interests, if only by reminding us that in the continuing process of adapting to the rangelands, rights have always been contested and negotiated rather than immutable.
Some aspects of tree-grass dynamics in Queensland's grazing lands
Authors: Scanlan J. C.
Published: December 2005

This review examines the interactions between grasses and trees that are relevant to Queensland's grazing lands. Soils and climate determine the potential amount of woody vegetation within an area and clearing, fire and grazing management can modify that potential. In general, the presence of non-leguminous trees reduces the potential grass production beneath their canopy and within woodland patches. Some non-native leguminous trees (e.g. Indian siris, Albizia lebbeck) enhance production of grasses beneath their canopies, whereas the widespread native leguminous trees, mulga (Acacia aneura) and brigalow (A. harpophylla) have not been reported to enhance grass production in the same way. At the patch scale, pasture production beneath woodlands with moderate to high tree basal areas is generally less than in open patches under the same soil and climatic conditions. At a landscape level, tree density, rainfall amount and distribution, and soil type modify pasture production within forest/woodland/shrubland systems. Grasses can reduce tree seedling survival but have little impact on mature woody plants, apart from providing fuel to carry a fire.
Modelling studies have been used to examine some aspects of tree-grass production. Firstly, the relationship between grass production and an increasing amount of trees can vary from linear decrease, to exponential decrease to initial stimulation followed by a decrease, depending solely on the relative strengths of stimulatory and competitive effects of trees on grasses. Secondly, simulated pasture production within woodlands shows that the pasture production may be up to 50% higher in paddocks that have high variability in the distribution of those trees compared with areas where trees are uniformly distributed. This is due to the non-linear (negative exponential) relationship between pasture production and tree density that is commonly observed within Queensland. Lastly, simulation studies show that total aboveground production (trees and pasture) of mulga woodland increases as the number of trees per hectare increases.
The pasture production response to tree clearing or tree planting depends on tree species, rainfall, soil type, climatic history and post-clearing management including fire and grazing, and will change with time since clearing. The greatest relative increase in pasture production following the removal of woody vegetation occurs: when the initial tree basal area is highest; where rainfall is evenly distributed though the year and on fertile soils with a low water holding capacity.
An economic analysis of sown pasture trends on the tablelands of south-eastern New South Wales
Authors: Vere D. , Dowling P.
Published: December 2005

The latter part of the 20th century has seen a persistent decline in the productivity of some types of sown pastures on the central and southern tablelands of New South Wales. Currently, much research effort is directed to stabilising the perennial grass component of these pastures. This paper evaluates the economic justification of that emphasis. It is argued that trends in livestock production can usefully represent increases or decreases in the stocks of three broad categories of sown pastures that are defined as being those pastures sown to introduced perennial grasses and legumes (perennial grasses), introduced legumes only (legumes), and the total of both these categories. Regression methods were used to determine the changes that have occurred in the livestock production from these pastures that could be explained by changes in a range of economic and other variables. The estimated models were then used to forecast wool, beef and lamb production from each pasture type. The results indicate that changes in prices and costs have influenced the trends in animal production from these pastures and that the structures of these influences have changed over time. Production from perennial grass-legume pastures has remained high relative to production from legume pastures despite adverse cost-price trends. The forecasts indicated a continuation of present levels of perennial grass-legume pasture areas but a decline in production from the legume pastures. The results support the concerns about the continued deterioration in the legume only pastures and the thrust of R&D programs that promote the benefits of perennial grass-legume pastures. The use and analysis of public data to improve understanding of the economic factors that influence the long-term stability of intensively grazed rangelands is highlighted.
Genotypic variation among sites within eleven Australian native grasses
Authors: Waters C. , Melville G. , Grice A.
Published: December 2005

Eleven species of native grass were collected from 51 sites throughout western New South Wales and south-west Queensland. Approximately 10 whole plants of each species were collected from a site but not all species were collected from each site. Plants were grown in a common environment at Trangie in central western New South Wales and plant morphological and floristic characteristics measured. Data reported here are for observations made in the third year, by which time differences between populations were likely to be more genetic than environmental. Principal component and discriminant analyses revealed a strong relationship between site of origin and plant morphological characteristics, which explained between 61% and 93% of the variation within species. For all but one species, site was significantly correlated with these morphological characteristics. Site could be predicted from morphological characters with a success rate usually greater than 80%. These morphological characteristics must reflect genotypic differences among the collection from the different sites.
We were unable to relate this variation to any of a range of site characteristics. Distance between sites could not be used as an indicator of morphological differences between populations. The implications of these findings are discussed in terms of providing strong evidence for the existence of ecotypes and for obtaining appropriate seed sources for revegetation/restoration programs.
Grazing distribution of free-ranging cattle at three sites in the Alice Springs District, Central Australia.
Authors: Hodder RM , Low WA
Published: December 2005

Cattle were obwrved over a period of five years on three sites near Alice Springs to determine how different plant communi- ties were utilized. Under extencive range management as practised in the Alice Springs district, the location of watering points was the major factor influencing forage utilization by cattle. The most favoured plant communities were those developed on riparian, swamp, and woodland site? and the location of these preferred communities, in relation to watering points, determined cattle distribution. No clear pattern of community preference between summer and winter could be detected. In good seasons the majority of cattle grazed within 4 km of the watering points. Only when forage conditions were poor did the majority graze beyond 8 km from water. The study as a whole showed that knowledge of plant community distribution and order of grazing preference by cattle, can bea useful tool in planning the location of water points and in protecting fragile rangeland.
The Influence of Liveweight on Group Size and Mating Efficiency in a Ewe Flock in an Arid Grazing Environment.
Authors: Gardiner HG , Wilcox DG , Morrissey JG
Published: December 2005

Group size, liveweight and pasture production were recorded for three years in a flock of 320 Merino ewes grazed under extensive management on degraded Muiga (Acacia aneura) - short grass and halophyte communities at Meekatharra, Western Australia. Lower pasture production induced lower liveweights which were strongly correlated to reduced group size. It is suggested that lower liveweights and increased numbers of groups reduced ewe-ram contact and mating efficiency in the flock.
The influence of grazing by sheep on the structure of a saltbush (Atriplex vesicaria Hew. ex Benth.) population.
Authors: Graetz RD
Published: December 2005

The population structure of a stand of saltbush (Atriplex vesicaria Hew. ex Benth.) was studied within one paddock by sampling the shruLq3opulationon a grid radiating from the only watering point. The pattern of both contemporary and cumulative grazing influence was found to be focussed on the watering point but it was not a simple symmetrical one. The existence and distribution of preferred grazing areas could not be explained by the data collected. There was a preferential grazing pressure of the female shrubs. The cumulative effects of this were reflected in a five-fold change in the sex ratio (males/females) of the shrub population.
Infiltrometer studies in rangeland plant communities of the Northern Territory.
Authors: Gifford GF
Published: December 2005

Infiltrometer studies were conducted within several plant communities near Alice Springs, Northern Territory. Plant commu- nities studied included mulga-perennial, mulga-shortgrass, savanna woodland, gilgai, flood-plain grassland, and scalded areas (no vegetation). Attempts were made to quantify the impact of surface crusting, antecedent soil moisture conditions, and time of year on infiltration rates and potential sediment yields. Results indicate that the infiltration process within certain plant communities is often complex, and hydrologic differences which occur both within and among the plant communities should be acknowledged. Sediment yields from a floodplain-grassland unit and a scald situation were about 2 and 5 times greater, respectively, than those from various mulga communities, woodland, or gilgai circumstances. With one exception, antecedent soil moisture had little influence on sediment yields. Removal of surface soil crusts significantly increased sediment yields, regardless of antecedent soil moisture conditions. The relationship between soil movement and loss and ecosystem stability needs to be established for most rangeland environments, but little has been done to satisfy this need.
Rangeland Hydrology in Australia - A Brief Review.
Authors: Gifford GF
Published: December 2005

Interest in Australian rangelands is increasing. This paper reviews various aspects of rangeland hydrology in Australia in the hope that it will stimulate further thought and research concerning this little understood, though vast, resource.
Observations on the effectiveness of warren destruction as a method of rabbit control in a semi-arid environment.
Authors: Martin JT , Eveleigh JN
Published: December 2005

The effectiveness of warren ripping as a method for controlling rabbits in a semi-arid environment was tested on a 3000 ha site at Kinchega National Park in western New South Wales. Estimates of rabbit numbers made during the study showed that the immediate effect of warren ripping was to reduce the rabbit population by about 65%. The longer term effect was to stabilise numbers at a relatively low level. The only warrens active 14 months after being ripped were those which gained new burrow entrances within two months of being destroyed. Re-opening rate of warrens was greatest for large limestone warrens where 90% of ripped warrens were again active after two months. Less than 30% of all sandy warrens became active again. Within each re-opened warren, the number of active entrances increased slowly but 14 months after being destroyed they had still not reached their original size.
Poisonous plants in Northern Territory rangelands.
Authors: Mitchell AS
Published: December 2005

The ten major poisonous plant species in the Northern Territory are discussed in terms of the habitat, distribution, and toxic components of each. The conditions most conducive to poisoning are also discussed, and range management recommendations outlined for each.
The financial management of Wilangee Station.
Authors: Smith WB
Published: December 2005

In this paper I hope to lead you through the financial history of Wilangee Station. Through the decisions we made, the
mistakes we have made, the lessons we have learnt, the debts we have taken on and the profits we have made. My aim is to expose
all of these facts so people may learn from them.
The effect of sample size and plot stratification on the precision of the wheel-point method of estimating botanical composition in clustered plant communities.
Authors: Lodge GM , Gleeson AC
Published: December 2005

A natural pasture in which there was contagious distribution of the species was sampled using a single wheel-point apparatus on which the interpoint distance exceeded the size of individual plants but was less than that of the plant clusters. The standard error of mean basal cover calculated from repeated independent samples was lower than that e\pected from a binomial distribution. The standard errors for five levels of sampling, with and without stratification of the plot are presented and these can be used to predict the sampling intensity needed to achieve an acceptable standard error for each mean basal cover. Either an increase in the number of points sampled over the whole-plot or shatification of points within the plot reduced the standard error of the mean estimate of basal cover. At all levels of sampling, stratification of point samples gave a substantially lower standard error and was more efficient in terms of field sampling time, than an increase in the number of points sampled. -
Management of the natural pastures of South-Western New South Wales.
Authors: Wilson AD
Published: December 2005

This paper reviews those aspects of the scientific literature that bear on the management of the native saltbush, grassland, belah and bluebush communities of south-west New South Wales. In includes information on the structure, vegetation change, erosion, animal production and management, and includes tables of the characteristics of the major plant species. Grazing can induce major vegetation changes in saltbush areas, but only relatively minor changes in the more stable communities, such as belah. Erosion hazards are severe in the bluebush communities, although they are generally stable at present. Animal production is closely related to the winter incidence of rainfall, when both sheep and cattle concentrate their grazing on annual plants. In summer saltbushes, bluebushes and copper burrs become the main constituents and diet quality is adequate for maintenance. Research suggests that controlled continuous grazing is the best option for both production and pasture management in these communities. The future use of controlled burning to reduce unpalatable shrubs in belah communities is indicated.
Soils of the Poplar Box (Eucalyptus populnea) communities of Eastern Australia.
Authors: Webb AA , Walker PJ , Gunn RH , Mortlock AT
Published: December 2005

Information on the soils of recognized poplar box (Eucalyptus populnea) communities has been collated from published and unpublished reports. Major soils have been described briefly in terms of morphology and some physical and chemical properties. Site data from a number of previous surveys was used in an attempt to identify soil type/vegeration relationships. Poplar box occurs on a very \\'ide range of soil types. Approximately half of the 1500 sites described in Queensland and New South Wales were on duple\ soils. The data indicate that poplar box prefers lighter textured soils such as uniform sands and massive earths in the western areas of its distribution but in the eastern, more mesic areas il occurs mainly on duplex clay soits.
Chemical and botanical composition of the diets of oesophageally fistulated sheep, cattle and goats in a semi-arid Eucalyptus populnea woodland community.
Authors: Squires VR
Published: December 2005

Diet samples collected from oesophageally fistulated sheep, cattle and goats on six occasions over a 12 month period were analysed for botanical and chemical composition. Angus steers, Merino wethers and feral goats were used in the study which was conducted in a poplar box (Eucalyptus populnea) woodland community near Cobar in northern N.S.W. Over 90 species, including trees and shrubs, were available to the livestock but only 18 species were eaten and of these, only five were of major consequence. These were the grasses, Eragrostis lacunaria and Stipa variabilis and the chenopods, Bassia diacantha, B. convexula and Chenopodium anidiophyllum. Other species to figure prominently in the diet were the composite forbs Calotis spp. and the shrub Acacia aneura.

Diet quality was generally low with percent N in the range 0.98-2.10% and in vitro digestibility values ranging from 42-61%. The diet quality varied throughout the year and between animal species at any one time of year. Sheep selected diets which were higher in nitrogen and which were more digestible than those selected by either cattle or goats.

Shrubs and trees were a major component of the diets of all three livestock species when the herb layer plants had been reduced to low levels of availability (< 180 kg/ha). Goats ate more trees and shrubs than either sheep or cattle at all times (P < 0.05) and these plants contributed up to 55 per cent of the goat's diet on occasion. The maximum contribution of shrubs to sheep and cattle diets was 22% and 34% respectively.

Management implications are discussed in the light of the ephemeral nature of the herbage layer and the nutritional needs of the livestock.
Nutrient deficiencies in central Australian semi-desert rangelands, with reference to decline in range condition.
Authors: Friedel MH , Cellier KM , Nicolson KP
Published: December 2005

Three central Australian' plant communities: Mitchell grassland, open woodland and mulga shrubland, were examined for
evidence of nutrient deficiencies, particularly in association with poor range condition. Twelve nutrients were applied in various
combinations to their soils in glasshouse pots trials. Two native grasses were grown in the Mitchell grassland and open woodland
soils, while a native grass and a native chenopod were grown in the niulga shrubland soils. A field study with three nutrients was
restricted to open woodland.
The grasses grown in Mitchell grassland and open woodland soils responded to added nitrogen, phosphorus and sulphur.
while the grass grown in mulga shrubland soil responded to added nitrogen and phosphorus only. The chenopod, grown in mulga
shrubland soil, responded to calcium as well as to nitrogen and phosphorus. In the field study, nitrogen improved plant growth
but not all species responded equally. Arisrida contorra, which acts as an indicator of poor range condition in open woodland.
formed a greater proportion of the herbaceous biomass following the addition of nitrogen. No response to phosphorus and sulphur
was detected in the field.
In both Mitchell grassland and open woodland, decreaser species (those whose biomass contributes proportionately less to
the total as range condition decreases) responded better under glasshouse conditions to phosphorus on soils from areas in poor
range condition than on soils from areas in good range condition. Of the species which increase with decreasing condition. that
from the grassland also responded better to phosphorus on soils from areas in poor range condition, while that from the woodland
was insensitive to phosphorus. In the mulpa shrubland, range condition was not associated with nutrient status.
Several nutrients may be deficient in central Australian rangeland soils but phosphorus is the only nutrient which is
potentially more deficient in degraded rangeland soils than on healthy rangeland soils. The evidence for a relationship between
range condition and phosphorus deficiency is, however, inconclusive.
An evaluation of large scale aerial photography for assessing range condition in central Australia.
Authors: Foran BD , Cellier KM
Published: December 2005

Largc scalc colour aerial photography was investigated as a method for assessing range condition of semi-desert rangelands in central Australia. Herbage layer spcics were selected which were good indicators of condition in three rangeland types, Open Woodland, Mulga with annual grasses and forbs and Mitchell grass Grassland. Two methods of photo interpretation were used in an attempt to distinguish between sites in different range condition on each of these rangeland types. These were: quantitative point counts on these indicator species; and qualitative visual rating scales of range condition. Both interpretation methods were successful on Mitchell Grassland where structure and colour of large tussock grass species aided photointerpretation. Smaller simd grass species, and differences between observers in their interpretations caused the methods to fail on the other rangeland types. This programme of testing was an intensive and thorou~rh one, and the results would indicate that further development of large scale aerial photography as a nionitoring tool for range condition is not warranted for rangelands in central Australia. In addition a comparison of both ground and aerial methods of range condition survey did not glve the aerial methods any advantage in time, cost or ease of operation.
The value of reference areas in the study and management of rangelands.
Authors: Michalk DL , Norton BE
Published: December 2005

Plant populat~on data for the pass white-top (Daiithoriia ~acs[~l,itosa) and for bladder saltbush (Atriplcx i~esicaria) were collected for four years from a pasture continuously pared by either cattle or sheep (at equivalent stocking rates) at a site near Booligal. Neu South Wales. Dur~ng the four )ears of the ekpenment the cattle and sheep had different Impacts on the grass and scrub components of thc pnsture Sheep tended to deplete the numbers of pass plants far more than d~d cattle, whereas saltbush shrub numbers Rere llttle affected b) elther type of stock. The ranfall pattern experlcnced throughout the ezpenment had a far greater ~nfluence on the ~~~rv~val of both grass and shrub than did grazlnp.
Production and water use of a wiregrass (Aristida spp.) pasture in South Western Queensland.
Authors: Pressland AJ , Lehane KJ
Published: December 2005

The productivity of wiregrasses (Aristida spp.), abundant and of low value in mulga lands, was observed on one field site under soil water conditions adequate for growth. Maximum growth rate in summer was 92 kg DM ha-1 d-1 , winter rates were 10% of this. Maximum herbage produced in November to February (summer) was 3600 kg ha-1 , compared with 570 kg ha-1 in April to June (winter). Standing root crop in mid-summer was 1065 kg ha-1. Because of their potential to rapidly produce a large biomass above ground and new inflorescences within 30 days after rain, wiregrasses will continue to be harmful species unless management techniques, based on weaknesses in their life cycle, are evolved.
Effects of land use on the solodic soils of the Poplar Box (Eucalyptus populnea) lands.
Authors: Tunstall BR , Webb AA
Published: December 2005

Information on soil changes under various forms of land use in poplar box (Eucalyptus populnea) lands on solodic soils is summarized and generalizations on the effects of management practices on the soil resource are made. The implications of the results for land use are considered and problems seen as requiring further research are outlined. Crazing by domestic livestock results in soil compaction which, through decreasing the infiltration rates, causes an increase in the surface run-off of water. These effects are enhanced by the killing of trees, and the associated changes in soil water content profiles are accompanied by changes in the distribution of soluble soil salts. Scalds develop in some areas. Tnese deleterious changes are reversed where there is shrub growth and livestock are excluded. The reasons for the development and persistence of scalds require further elucidation. In particular, the conditions requited for the recruitment of grass and shrub species, and the relative importance of the various pathways for salt movement in these systems, should be defined.
Fire in Pastoral Areas of Poplar Box (Eucalyptus Populnea) Lands.
Authors: Walker J , Condon RW , Hodgkinson KC , Harrington GN
Published: December 2005

Fire has been present during the evolution of poplar box communities and the flora is well adapted to fire. Broad fire regions are recognised on the basis of bioclimatic data and the effects of different fire regimcs on plant species and communities arc dis- cussed in relation to these regions. Grazing combined with the variable rainfall makes the accurate prediction of vegetation changes resulting from fire difficult. Fire is currently episodically associated with over-average rainfall in most areas as the predominant fuel is grass. Minimum fuel quantities of 100 g m-2 in pastures where fuel is continuous and 150 g m-' in pastures with discrete tussocks are required to carry a fire. Fire can drastically reduce shrub numbers, especially juvenile and seedling plants in the short term, but attitudes about using fire for shrub reduction vary from region to region according to the likelihood of growth or replacement pastures. Grazing control after burning to permit the recovery of the ground layer is difficult because of grazing by native herbivores. There is a need for further studies on fire behaviour and plant survivorship characteristics as affected by climate and native and domestic animal grazing.
Hydrological processes and herbage production in shrub invaded Poplar Box (Eucalyptus populnea) woodlands.
Authors: Johns GG
Published: December 2005

The hydrological processes of relevance to herbage production in shrub invaded semi-arid popla box (Eucalvptus popuhea) woodlands are reviewed. Climatic limitations to herbage production in the poplar box lands are discussed in relation to the annual distribution of rainfall and evaporation. The limiting effects of trees and shrubs on herbage production within a woodland are then evaluated using data from a study site near Coolabah in north-western New South Wales. Hydrologic measurements made at the site include soil water storage, run-off and infiltration rates. Marked spatial variability in infiltration of water into the soil was in part related to the distribution of plants and redistribu- tion of water from ridges to adjacent flats occurred because of low rates of infiltration into bare soil areas between groups of trees and shrubs. From measurements of the depletion of soil water which accumulated during an exceptionally wet period the potential rate of evapotranspiration from the poplar box component of the woodland was estimated to be 0.5 times that from a free water surface. Bare soil evaporation accounted for approximately one half of water losses. Herbage production is shown to be poorly related to soil water storage alone, but the regression between herbage production and the product of water and nitrogen availabilities accounts for 70% of the vari~ce. It is concluded that the role of trees and shrubs in competing with herbage for nutrients, as well as water, is in need of clarification.
Aspects of the population ecology of Galvanised Burr (Sclerolaena birchii).
Authors: Auld BA
Published: December 2005

The population ecology of galvanised burr, Sclerolaena birchii (syn. Bassia birchii), at a site in semi-arid N.S.W. is
described. Data were obtained from permanent quadrats, fenced and unfenced, with marked plants, using a quadrat with vertical
height adjustment for locating individuals. Deliberately buried woody fruiting perianths ('burrs') were monitored for wall breakdown,
which permits seed germination. There was no appreciable effect of grazing on the species population dynamics. Once
established, few plants survived for more than two years. Populations exhibited Deevey type 111 survival curves which could be
related to tap root growth and rainfall. Maximum breakdown of fruiting perianths occurred in 1 to 4 years. Provided rainfall was
sufficient for germination and establishment, flushes of galvanised burr populations might be expected at intervals of 5 to 7 years.
Because of the irregularity of effective rainfall in semi-arid eastern Australia 'burr years' occur less frequently. An explanation
for their occurrence after droughts is presented.
Tiller development as a possible factor in the survival of the two grasses, Aristida armata and Thyridolepis mitchelliana.
Authors: Brown RF
Published: December 2005

Early tiller development of both Aristida armata and Thyridolepis mitchelliana, determined by microscopic dissection, was
comparatively rapid, possib1y reflecting adaptation to an unpredictable environment.
Little difference was found between the species in the timing of transition from vegetative to reproductive development at
the growing point or in exertion of the inflorescence, although there were marked differences in the rate of elevation of the
growing point. The Aristida growing point spent a greater period of time close to the tiller base where it would be relatively
inaccessible to grazing. Such behaviour may help explain why Aristida armata appears to displace Thyridolepis mitchelliana in
overgrazed pastures.
Effect of sowing depth and seedling morphology on establishment of grass seedlings on cracking black earths.
Authors: Watt LA , Whalley RDB
Published: December 2005

There is a wide range in the ability of grasses to become established on the cracking black clays of the Inverell district.
Some native grasses establish readily on cracking black soils but most of the introduced perennial summer growing grasses are very
difficult to establish. This study compared a number of native and introduced grasses in terms of establishment capability, depth
of sowing and seedling morphology.
In general there was a poor association between establishment capability of a species and the ability of its seedlings to
emerge from depth. However, a well developed primary root system and a low shoot to root ratio were generally associated with
good establishment capability. The results presented in this paper support the view that a number of seed and seedling features
are involved in the progression from a germinating seed through to an established seedling. Species which occupy similar habitats
may or may not have similar features.
Runoff and soil loss in a semi-arid shrub invaded Poplar Box (Eucalyptus populnea) woodland.
Authors: Johns GG
Published: December 2005

The ridges of the Cobar pediplain generally have only a sparce herbage cover. Much of the incident rainfall is reputed to run off, perpetuating the low pasture productivity and causing erosion. Woody shrubs have often invaded the woodlands of the pediplain. On some gentler sloping (1%) ridges dense patches of shrubs surround large eucalypts and together are known as 'thickets'. Between these thickets relatively sparsely shrubbed areas ('interthickets') occur.

Runoff from small plots situated in thicket and interthicket areas of shrub invaded poplar box woodland was recorded during 1975-1981. Half the plots had been partially cleared by pushing over all shrubs with a bulldozer ('shrub-pushed', in contrast to 'unpushed'). Soil losses from the plots were measured over a four year period.

Rainfall during the study was 26% greater than the long term average for the area, and provided many runoff events, particularly from intense summer storms. Runoff averaged 26% of rainfall for unpushed interthicket areas while thicket runoff was negligible. Runoff from the shrub-pushed plots was c. 25% less than from their unpushed counterparts, but this difference was not significant at P < 0.05. During the December-March period monthly runoff from unpushed interthicket plots averaged 41% of monthly rainfall in excess of 12 mm, while for the other eight months runoff averaged 24% of monthly rainfall in excess of 9 mm.

Soil losses were greater during the stormier part of the year, with long term soil loss rates equivalent to 25 mm per 1000 years from enclosed interthicket plots and 55 mm per 1000 years from the gra7ed interthicket plots. Shrub-pushing appeared to increase soil losses in the short term but after two years soil loss rates decreased to be less than those from unpushed plots.

Estimates of likely interthicket runoff based on long term rainfall records had a median value of 77 mm per year, or only 64% of that observed during the study period. Over the 88 years the 5 year moving average of estimated runoff fell to as low as 40 mm per year. The results are discussed in the context of waterspreading.
The application of Landsat image data to rangeland assessment and monitoring: An example from South Australia.
Authors: Graetz RD , Gentle MR , Pech RP , O'Callaghan JF , Drewien G
Published: December 2005

The potential of Landsat image data to assess and monitor an area of semi-arid rangelands in South Australia is demonstrated. The project is a cooperative ongoing one between CSIRO and a future operational user of Landsat, the South Australian Pastoral Board, and it has as its long-term aim the development of a Land Image-Based Resource Information System (LIBRIS) for rangeland management. Three separate stages of the project are described. The fist is the integration of tenure maps with Landsat image data to permit a useful analysis and interrogation of the combined Landsat data sets. The second is the derivation of vegetation indices from Landsat data that are applicable to the semi-arid rangelands. Indices of 'cover' and of 'greenness' have been derived, but this report concen- trates on the cover index only for it can be related to soil erosion hazard/landscape stability and, as such, it represents a simple, robust vegetation-related index derived directly from Landsat. Lastly this index is used to map both cover and trend (changes in cover). Cover changes over the period 1973-1980 are detected and reported for a test region of 8300 km2. With the integration of tenure boundaries the interrogation, mapping and reporting at the individual property level is demonstrable.
Relationship of aircraft radiometric measurements to bare ground on semi-desert landscapes in central Australia.
Authors: Foran BD , Pickup G
Published: December 2005

Radiance values in Landsat MSS bands were measured over five landscapes typical of central Australia: a calcareous plain, an eroded calcareous plain, a gibber plain, a floodplain and a savannah woodland. using an aeroplane-mounted isotech four band radio- meter flown at a height which gave Landsat pixe!-sixed sampling areas. Forty-five radiometric variables derived from these radiance data were correlated with the amount of bare soil interpreted frotn aerial photos. On the calcareous plains and the floodplain, the highest correlations were obtained with the visible bands, Band 4 and Band 5, and the difference between them. On the gibber plains and savannah woodlands the best correlations were obtained with the ratio of Band 5 to Band 7 and the subtraction ratio of B4-B5/ B4-B7. A series of linear relationships were developed linking bare ground \vith radiometric variables which expl'ained between 705% and 85% of the variation. Multiple regression analysis on the radiometer indiccs most highly correlated with total bare ground showed that inclusion of other cover variables such as litter, shadow, soil colour and herbage covcr increased the variation explained by only 5-10%. A test of the effect of differences in solar elevation angle on the 45 radiometric variables showed that the radiance values in each band and differences between them \$cue significantly affected. Eight indices were affected to a lesser degree and may bc useful for multi- temporal work. Some considerations of the use of the selected indices for practical landscape monitoring are also discussed.