Showing papers in "Rangeland Journal in 1976"

A non-destructive method for estimating the weight of forage on shrubs.

Abstract: A technique for estimating shrub forage weight is described and the results of testing it on saltbush and bluebush are presented. The accuracy and precision, speed and simplicity, and independence of special equipment of the technique are all demonstrated. Although similar in principle to techniques known to have been used in Australia (but nowhere described in detail), the present technique has distinctive features and is designated the 'Adelaide' technique.

A method for the analysis of piosphere data applicable to range assessment.

Abstract: The logistic growth curve equation of population biology is shown to satisfactorily describe the responses of some vegetation and soil measures as a function of distance out from a watering point. Two of the three parameters of this equation can be readily related to parameters of the herbivore - rangeland ecosystem. The potential use of this equation is explored for the development of a simple, quantitative range assessment method. -

The Effects of European Settlement and Domestic Livestock on the Biological System in Poplar Box (Eucalyptus populnea) Lands.

Abstract: This article outlines the exploration and settlement of poplar box lands which followed the European occupation of the Australian continent in the mid-19th century, draws attention to the various fragments of historical information on substantial changes in the soils, vegetation and biota, and describes the role of European livestock (sheep, cattle, goats, rabbits) and fire in these changes.

Grazing distribution of free-ranging cattle at three sites in the Alice Springs District, Central Australia.

Abstract: 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.

General effects of management and grazing by domestic livestock on the rangelands of the Northern Tablelands of New South Wales.

Abstract: Three major pasture types probably occurred on the Northern Tablelands prior to European settlement. The dominants were probably Poa sieberana Spreng. and Themeda australis (R.Br.1 Stapf. at the higher elevations, T. australis, P. Sieberana and Sorghum leiocladum (Hack.) C.E. Hubbard on fine textured soils at lower elevations and T. australis, Aristida ramosa (R.Br.) and Cymbopogon refractus (R.Br.1 A. Camus. on coarse textured soils. The subsidiary species composition of these pasture types is also suggested, derived from fragmentary early accounts, earlier published work and observations on the behaviour under grazing of the different species involved. The characteristics of the important native and naturalised grass species are described. These species are classified into warm season perennials, warm season annuals, cool season perennials and cool season annuals. The native warm season perennials is the largest group of species at present on the Tablelands. The effects of grazing on the species composition of natural pastures is described. The grazing behaviour of merino sheep leads to a striking zonation of herbaceous species resulting from uneven grazing intensity and distribution of dung and urine. Data from an unreplicated stocking rate by superphosphate application rate trial at Shannon Vale are presented. This trial indicated that the proportion of white clover in the pasture depended on both stocking rate and superphosphate rate and that the proportion of Danthonia spp. increased when white clover decreased. Wool production data are also presented which show that high levels of pro- ductivity per hectare can be obtained from topdressed natural pastures. A number of different natural pasture types occur on the Tablelands. A schemeis presented showing the interrelationship$ between the original and the present pasture types as affected by grazing intensity and the addition or depletion of plant nutrients.

The effects of feral goats and sheep on the shrub populations in a semi--arid woodland

Abstract: Shrubs are increasing in density in extensive areas of semi-arid woodland in Queenstand and New South Wales, reducing their carrying capacity for stock and increasing the difficulty of sheep management. A case study is reported in which an area exclosed from grazing increased from 6000 to 9000 shrubslha in 3 years. Grazing by sheep or goats both reduced the establishment ofAcacia aneura (mulga) and Dodonaea 11iscosa (broad-leaf hopbush) seedlings. Cassia spp. (punty and silver cassia), Eremophila sturtii (turpentine), E. rnitchellii (budda) and Geijera parviflora (wilga) were not reduced. Sheep did not affect mature shrubs to any extent. Extremely heavy goat pressure destroyed several problem shrubs, including Acacia arzeura and Dodorzaea viscosa, and reduced Cassia spp. Mechanical shrub-clearing is often followed by sprouting from the roots of some species. Moderate goat pressure failed to control such sprouts; heavy goat pressure eliminated sprouts from E. rnitchellii and G. parviflora but E. sturtii was not eaten, probably because of its higher oilcontent, and increased to 166% of its preclearing density in two years. Mechanical clearing increased shrub seedling establishment four-fold. Future increases in shrub density may be expected in semi-arid woodland communities and goats do not offer an answer to the problem because they are selective between species and because managerially significant reductions in shrub populations can only be achieved at extremely high stocking pressures. The expense of fencing for such a treatment, the damage to the herb layer and the lack of a post treatment management, that would prevent the replacement of palatable shrubs by unpalatable ones, makes it an unsuitable technique for extensively grazed properties.

Western Myall (Acacia sowdenii), its survival prospects and management needs.

Abstract: Studies on western myall rangelands are reported which show from population structure that Acacia sowdenii woodlands will not survive under present circumstances. Evidence is evaluated to allow informed discussion of landuse and management options affecting western myall.

The Shrubs of Poplar Box (Eucalyptus populnea) Lands and their Biology.

Abstract: Of the 25 species of shrubs common in poplar box lands, 17 are considered to have reached the status of being a "woody weed" in New South Wales and/or Queensland. Thickening up of scrub in pastoral areas appears to have been episodic after periods of above-average rainfall. Germination of seed may occur at most times of the year if soil moisture is high. Fire promotes germination of species with hard seeds (some Acacia, Cassia and Dodonaea spp.). Increased shrub density usually follows soil disturbance if seed is present, and once established, the individuals of most apecies appear to be long-lived. Productivity of shrub communities is commensurate with rainfall. The species are well adapted to tolerate drought and they retain leaves under extreme water stress. Most species flower and set seed each year in the spring and summer period but in more arid parts of poplar box lands some species reproduce opportunistically after good rainfall. In favourable conditions most species produce copious quantities of seed. Dormancy is common in seed recently shed and loss of dormancy may occur within months or up to 3 years after seed shed. All species are subject to invertebrate and vertebrate predation and death of individuals or whole populations may sometimes result. A few species are moderately palatable to domestic livestock and native herbivores; the majority are rarely eaten even by starving animals. The regenerative ability of shrubs following fire or grazing differs amongst species and is affected by shrub size.

The influence of grazing by sheep on the structure of a saltbush (Atriplex vesicaria Hew. ex Benth.) population.

Abstract: 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.

Walking, Watering and Grazing Behaviour of Merino Sheep on Two Semi-Arid Rangelands in South-West New South Wales.

Abstract: Distance walked per day, time and frequency of drinking, volume of water consumed and grazing distribution of Merino sheep flocks on a saltbush (Atriplex vesicaria) and a grassland (Danthonia caespitosalStipa variabilis) community were assessed during summer. Both sites were located within the same region and observed simultaneously for three consecutive days in each of the four months December, January, February and March. The sheep on the saltbush site (1 3 10 ha) grazed as a single flock or as several large subflocks ( >300 sheep) and spent much of their time grazing on a relatively small proportion of the paddock. Drinking frequency was once daily in early summer and twice daily in late summer. The volume of water consumed varied from 2.3 l/day in December to 9.3 l/day in March. Average daily distance walked reflected the change in frequency of drinking and ranged from 8 km/day in December (once daily drinking) to 14 km/day in March (twice daily drinking). Subgrouping occurred on the grassland site (910 ha) where as few as two or three sheep would graze at distances of 10-200 m from other subgroups. Drinking frequency was once daily and volume of water consumed varied from 0.6 l/day in early summer (December) to 3.1 l/day in late summer (March). Average daily distance walked was 4.7 km/day with a peak of 6.2 km/day in late summer when forage on offer had fallen to low levels.

Computer simulations of sheep grazing in the arid zone.

Abstract: The thesis emphasises a review and comparison of submodels applicable to arid or semi-arid zone grazing systems, but includes original field work and data analysis where necessary. Several published models of nonspecific arid zones sites were taken as a basis for this project. The detail with which the spatial variability of the grazing processes are simulated, distinguishes this model from most published grazing models. The paddock model includes 37 cells (point models) and simulates the hourly movement and behaviour of up to 10 flocks within them.

A survey of the regeneration of some problem shrubs and trees after wildfire in western New South Wales.

Abstract: The regeneration of several shrub and tree species in western New South Wales was recorded after widespread natural fires in the summer of 1974175. At 25 locations, plots were established in the wake of the fires and observations were recorded of the rue damage, the regrowth of the plants and post-fire seedling establishment. Interest was centred on species regarded as woody weeds. Fourteen months after the fires, the average survival of seven of the most common species was: Callitris columellaris (white cypress pine) 275, Acac~a aneura (mulga) 16%, Dodonaea attenuafa (narrow-leaved hopbush) 26%, Cassia eremophila var. platvpoda (punty) 48%, Acacia homalophylla (yarran) 87%, Eremophila mitchell~i (budda) 88% and Eremophila sturtii (turpentine) 87%. These results are for plants whose leaves were totally scorched or burnt. For Dodonaea attenuafa and Cassia eremophila there was a large difference in recovery between locations, a difference which was not explicable in term of fire intensity or shrub size. Post-fue seedling establishment occurred with these two shrubs, particularly with D. attenuata, which had high seedling numbers on eight of the eleven locations.

Possible effects of removal of Mulga on rangeland stability in South Western Queensland.

Abstract: Thinning or complete clearing of dense mulga (Acacia aneura) woodlands in south western Queensland may lead to undesirable rangeland conditions unless sound property management is practised. Even ten years after thinning, ground storey vegetation in an ungrazed situation is still in a state of flux. Livestock management following clearing can markedly influence pasture composition and mulga regeneration. Poor rangeland management may lead to reductions in pasture basal area sufficient to reduce productivity and accelerate degeneration through soil and nutrient losses in run-off waters.

A note on the effects of browsing by feral goats on a Belah (Casuarina Cristata) - Rosewood (Heterodendrum Oleifolium) woodland.

Abstract: In a Belah - Rosewood woodland in western New South Wales, stocking with feral goats over a four year period effected changes in the composition of the tree and shrub component. The most readily browsed tree was Rosewood and mature trees of this species were stripped of foliage to a height of 2 m. At an early stage Desert broombush (Templetonia egena) and young Warrior bush (Apophyllum anomalum) were severely damaged and young Yarran (Acacia homalophylla) and Belah defoliated. Most defoliated Yarran died within the observation period. Two shrubs regarded as weed species, Punty bush (Cassia eremophila var. platypoda) and Desert cassia (C. eremophila var. coriacea) were heavily browsed in the third year and subsequently eliminated. The weed shrub Turpentine (Eremophila sturtizl was not browsed at any time.

Effect of sheep grazing Astrebla grassland in Central Western Queensland.

Abstract: This thesis examines the effects of grazing pressure on plant responses in Astrebla grassland and the plant responses to rainfall at sites of different grazing pressure.Three commercially grazed paddocks in Astrebla grassland near Blackall, central-western Queensland were selected for study on the basis of a history of light, medium or heavy grazing pressure. Summer rainfall at each property prior to and during this experiment was quatified using a simple water balance model.Increased grazing pressure reduced the projected foliage cover of Astrebla spp., the basal area of which was similar under light and medium grazing pressure and was reduced under heavy grazing pressure. Differences in the density and size of Astrebla spp., tussocks were apparent under the three grazing pressures. n

Standards for testing and assessing range condition in central Australia.

Abstract: The development of range condition assessment in central Australia has been subjected to a series of tests of the relative performance of two existing methods, and of between observer repeatability. The results argue for the adoption of the method using floristic composition as the index of range condition, and adaptions to the method are suggested for its successful use in a variety of rangeland types.

A quantitative evaluation of Landsat imagery of Australian rangelands.

Abstract: The capability of multidate, multispectral ERTS-1 imagery of three different rangeland areas within Australia was evaluated for its usefulness in preparing inventories of rangeland types, assessing on a broad scale range condition within these rangeland types, and assessing the response of rangelands to rainfall events over large areas. For the three divergent rangeland test areas, centered on Broken W, Alice Springs and Kalgoorlie, detailed interpretation of the imagery only partially satisfied the information requirements set. It was most useful in the Broken Hill area where fenceline contrasts in range condition were readily visible. At this and the other sites an overstorey of trees made interpretation difficult. Whilst the low resolution characteristics and the lack of stereoscopic coverage hindered interpretation it was felt that this type of imagery with its vast coverage, present low cost and potential for repeated sampling is a useful addition to conventional aerial photography for all rangeland types.

Effect of fertility level on the yield of some native perennial grasses on the North-West Slopes, New South Wales.

Abstract: The effect of fertility on the yields of native perennial grasses was investigated in pot culture and field experiments. Yields of six native perennial grasses and Paspalum dilatatum Poir were determined in the glasshouse at five levels of applied phosphorus (P), sulphur (S) and nitrogen (N) and in the field the biomass of individual tussocks of eight native grasses was compared. In pot culture the maximum yields of the native perennial grasses with P, S and N applied were 15 to 75% lower than those of P. dilatatum. Within the native grasses there were significant yield differences: Bothriochloa macra (Steud) S.T. Blake, Chloris truncata R.Br. and Dichanthium sericeum (R. Br.) Camus yielded up to twice as much dry matter as either Aristida ramosa R.Br., Sporobolus elongatus R.Br. or Eragrostis leptostachya Steud. These data indicate that P, S and N are all essential for maximum yield of some native grasses, and large imbalances in the level of these nutrients resulted in seedling mortalities in most native grasses.

Herbage condition assessment of an infertile range grassland based on site production potential.

Abstract: The herbage production of mixed native mulga grassland communities, all differing in basal area, was measured between October and March each year over a four year period. The four seasons differed in total precipitation and length of, as well as continuity of the growing period. Basal area was found to be well correlated with peak standing grass biomass and with litter and root yield. Furthermore, basal area was found to be an adequate index of potential grass production irrespective of year. Basal area could be used as a determinant for condition assessment of these grassland communities growing on infertile soils, as well as an indicator of stocking rate. Photographic standards for field use are presented.

Reproductive performance of beef cattle in the Northern Territory.

Abstract: Reproductive wastage is a serious economic problem in the northern area of the Northern Territory. The reproductive efficiency of beef cattle (26,000) was studied over a three year period on a number of commercial beef producing properties in tropical Northern Territory. This area encompassed a range of environments, varying from northern high rainfall areas (Darwin and Gulf) to the southern semi-arid rangelands (Barkly Tablelands and Victoria River District).

Productivity and reponse to nitrogen fertilizer of the native grass Danthonia racemosa (Wallaby Grass).

Abstract: On the Northern Tablelands of New South Wales, Danthonia racemosa sown in both a field study and a pot experiment produced as much dry matter as any sown exotic grass species. Dry matter production of D. racemosa was least affected by dry weather conditions in the field while in pots it proved equally as responsive asphalaris tuberosa to nitrogen fertilizer. However, production of D. racemosa during winter was lower than P. tuberosa.

Observations on the effectiveness of warren destruction as a method of rabbit control in a semi-arid environment.

Abstract: 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.

Seasonal variations in the leaf fall and quality of the leaves of four Australian fodder trees.

Abstract: The effect of season of year on the extent of leaf fall, and the nutritive value of plucked and fallen leaves of four tree species growing in a Belah-Rosewood woodland in western New South Wales was examined over four years. Leaf fall was not correlated with rainfall but tended to a maximum in summer and autumn. There were substantial differences between species in the extent of leaf fall and in nutritive value of the leaves. Fallen leaves were of lower nutritive value than leaves plucked from the trees. The most digestible species, Wilga, yielded 21 kg/ha of leaf fall per year, whereas the least digestible, Belah, yielded 113 kg/ha. The low digestibility of the most common tree, Belah, renders it of little value as a drought reserve, but the less abundant Wilga and Rosewood are of value in supplying protein and energy in drought conditions. The amount of phosphorus returned to the soil via leaf fall would be insufficient to enhance herbaceous production beneath the trees.

Observations on the regeneration of shrubs and woody forbs over a ten year period in grazed quadrats on Mileura Station, Western Australia.

Abstract: Observations are reported on the regeneration of shrubs within grazed quadrats in inland Western Australia (26' 22's; 117' 20'~). The observations showed that in a ten year period of slightly above average rainfall, an increase in number of individual plants occurred in 24 out of 30 species of shrubs. No change occurred in four species and a decrease in numbers was observed in two species. Figures are given of the stocking rate of merino sheep on each quadrat in each year. Although no overall differences in amount of regeneration was observed in quadrats subjected to different stocking rates, within the range of rates occurring in this study (6.9 to 13.7 ha per sheep) individual species did show trends indicating different rates of regeneration under different stocking rates. Eremophila fraseri regenerated faster in quadrats experiencing high stocking rates than in those experiencing low ones and the reverse trend was shown by Solanum ashbyae and Acacia tetragonophylla. The Eremophila is considered unpalatable to stock whereas both the Solanum and the Acacia are eaten by sheep. Such trends could lead, eventually, to changes in species diversity in the area. The results of these observations suggest that the regeneration of rangeland shrubs is not incompatible with commercial stocking rates at Mileura.

The effects of grazing and season on the stability of Chloris Spp. (Windmill grasses) in natural pasture at Trangie, New South Wales.

Abstract: A study of the density and basal diameter of Chloris acicularis Lindl (syn Enteropogon acicularis (LindlJLazar - curly windmill grass) and C truncata R Br (windmill grass) was made at two stocking rates over a period of eight years The propor- tion of ground covered by these Chloris species varied widely with season, and to a lesser extent with grazing pressure The density of both species increased in good seasons, while the mean diameter decreased because of the number of new seedlings Although C truncata seedlings were more numerous in good seasons, they did not survive as well as did C acicularis seedlings during prolonged dry periods

The effect of sample size and plot stratification on the precision of the wheel-point method of estimating botanical composition in clustered plant communities.

Abstract: 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. -