Journal articles on the topic 'Pasture ecology Queensland'
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1
Silcock, R. G., T. J. Hall, P. G. Filet, A. M. Kelly, D. Osten, and T. W. G. Graham. "Floristic composition and pasture condition of Aristida/Bothriochloa pastures in central Queensland. II. Soil and pasture condition interactions." Rangeland Journal 37, no. 2 (2015): 217. http://dx.doi.org/10.1071/rj14107.
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Sustainable management of native pastures requires an understanding of what the bounds of pasture composition, cover and soil surface condition are for healthy pastoral landscapes to persist. A survey of 107 Aristida/Bothriochloa pasture sites in inland central Queensland was conducted. The sites were chosen for their current diversity of tree cover, apparent pasture condition and soil type to assist in setting more objective bounds on condition ‘states’ in such pastures. Assessors’ estimates of pasture condition were strongly correlated with herbage mass (r = 0.57) and projected ground cover (r = 0. 58), and moderately correlated with pasture crown cover (r = 0.35) and tree basal area (r = 0.32). Pasture condition was not correlated with pasture plant density or the frequency of simple guilds of pasture species. The soil type of Aristida/Bothriochloa pasture communities was generally hard-setting, low in cryptogam cover but moderately covered with litter and projected ground cover (30–50%). There was no correlation between projected ground cover of pasture and estimated ground-level cover of plant crowns. Tree basal area was correlated with broad categories of soil type, probably because greater tree clearing has occurred on the more fertile, heavy-textured clay soils. Of the main perennial grasses, some showed strong soil preferences, for example Tripogon loliiformis for hard-setting soils and Dichanthium sericeum for clays. Common species, such as Chrysopogon fallax and Heteropogon contortus, had no strong soil preference. Wiregrasses (Aristida spp.) tended to be uncommon at both ends of the estimated pasture condition scale whereas H. contortus was far more common in pastures in good condition. Sedges (Cyperaceae) were common on all soil types and for all pasture condition ratings. Plants identified as increaser species were Tragus australianus, daisies (Asteraceae) and potentially toxic herbaceous legumes such as Indigofera spp. and Crotalaria spp. Pasture condition could not be reliably predicted based on the abundance of a single species or taxon but there may be scope for using integrated data for four to five ecologically contrasting plants such as Themeda triandra with daisies, T. loliiformis and flannel weeds (Malvaceae).
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Kaur, K., R. K. Jalota, D. J. Midmore, and J. Rolfe. "Pasture production in cleared and uncleared grazing systems of central Queensland, Australia." Rangeland Journal 27, no. 2 (2005): 143. http://dx.doi.org/10.1071/rj05012.
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Clearing land of trees and introducing exotic pastures to enhance pasture and cattle production and hence enterprise financial performance are widely practised in Queensland. The results from many previous studies on tree clearing have emphasised the gains in pasture production, but over periods of less than 10–15 years after clearing. The present study questioned the sustainability of pasture production in cleared systems over a longer time-frame (>10 years of clearing). For this, three different age groups of clearing i.e. 5 year, 11–13 year and 33 year were selected in each of 3 major types of tree communities i.e. Eucalyptus populnea, E. melanophloia and Acacia harpophylla in central Queensland. Paired comparisons of cleared and uncleared (intact) pasture systems were selected for each age group of clearing. The results suggest that the initial gains in pasture production upon clearing were compatible with published studies. However, for longer periods of time since clearing, the gains in pasture production were not sustained and were accompanied by risks of land degradation and loss of pasture plant diversity. For E. populnea and A. harpophylla, the maximum benefits from clearing were achieved at 13–15 years whereas for E. melanophloia, any benefits existed only over a short period of 5–6 years. The study emphasises that each tree community exhibits a specific response with regard to the duration of increased pasture production following clearing. To estimate the total benefits from tree clearing in pasture development, it is important to consider both monetary benefits and non-monetary losses from clearing for different types of tree communities.
3
Silcock, R. G., T. J. Hall, P. G. Filet, A. M. Kelly, D. Osten, C. M. Schefe, and P. T. Knights. "Floristic composition and pasture condition of Aristida/Bothriochloa pastures in central Queensland. I. Pasture floristics." Rangeland Journal 37, no. 2 (2015): 199. http://dx.doi.org/10.1071/rj14106.
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A survey was conducted in central inland Queensland, Australia of 108 sites that were deemed to contain Aristida/Bothriochloa native pastures to quantitatively describe the pastures and attempt to delineate possible sub-types. The pastures were described in terms of their floristic composition, plant density and crown cover. There were generally ~20 (range 5–33) main pasture species at a site. A single dominant perennial grass was rare with three to six prominent species the norm. Chrysopogon fallax (golden-beard grass) was the perennial grass most consistently found in all pastures whereas Aristida calycina (dark wiregrass), Enneapogon spp. (bottlewasher grasses), Brunoniella australis (blue trumpet) and Panicum effusum (hairy panic) were all regularly present. The pastures did not readily separate into broad floristic sub-groups, but three groups that landholders could recognise from a combination of the dominant tree and soil type were identified. The three groups were Eucalyptus crebra (narrow-leaved ironbark), E. melanophloia (silver-leaved ironbark) and E. populnea (poplar box). The pastures of the three main sub-groups were then characterised by the prominent presence, singly or in combination, of Bothriochloa ewartiana (desert bluegrass), Eremochloa bimaculata (poverty grass), Bothriochloa decipiens (pitted bluegrass) or Heteropogon contortus (black speargrass). The poplar box group had the greatest diversity of prominent grasses whereas the narrow-leaved ironbark group had the least. Non-native Cenchrus ciliaris (buffel grass) and Melinis repens (red Natal grass) were generally present at low densities. Describing pastures in terms of frequency of a few species or species groups sometimes failed to capture the true nature of the pasture but plant abundance for most species, as density, herbage mass of dry matter or plant crown cover, was correlated with its recorded frequency. A quantitative description of an average pasture in fair condition is provided but it was not possible to explain why some species often occur together or fail to co-exist in Aristida/Bothriochloa pastures, for example C. ciliaris and E. bimaculata rarely co-exist whereas Tragus australianus (small burrgrass) and Enneapogon spp. are frequently recorded together. Most crown cover was provided by perennial grasses but many of these are Aristida spp. (wiregrasses) and not regarded as useful forage for livestock. No new or improved categorisation of the great variation evident in the Aristida/Bothriochloa native pasture type can be given despite the much improved detail provided of the floristic composition by this survey.
4
Orr, DM, CJ Evenson, DJ Jordan, PS Bowly, KJ Lehane, and DC Cowan. "Sheep productivity in an Astrebla grassland of south-west Queensland." Rangeland Journal 10, no. 1 (1988): 39. http://dx.doi.org/10.1071/rj9880039.
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A grazing study conducted between 1979 and 1983 assessed the seasonal trends of ewe productivity in Astrebla grassland in south- western Queensland. This study was designed originally to compare productivity on two pastures with different compositions, however, these differences in pastures composition were not achieved. Large differences in liveweight, wool growth and reproductive performance occurred between years in response to differences in pasture growth resulting from large variation in the seasonal incidence of rainfall. Rainfall effective for plant growth, both forbs and grasses, resulted in a high quality diet which resulted, in turn, in increased sheep productivity. Reproductive performance was particularly sensitive to the quality of the ewes diet around the time of lambing through the effect of diet quality on lamb survival and growth rate. It is suggested that the effect of rainfall on reproductive performance is pasture.
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Kaur, Kamaljit, David J. Midmore, Rajesh K. Jalota, and Nanjappa Ashwath. "Pasture composition in cleared and uncleared woodlands." Australian Journal of Botany 54, no. 5 (2006): 459. http://dx.doi.org/10.1071/bt05174.
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Land clearing in Queensland is often practised to enhance pasture production, and hence, increase financial returns from beef production. The benefits of clearing have been quantified in terms of short-term gains in pasture yield but have not adequately accounted for possible medium- or longer-term impediments that may be attributed to clearing. Therefore, impacts of clearing and the subsequent sowing of exotic grasses such as Cenchrus ciliaris L. on pasture composition and production were studied. To achieve this, paired sites were selected representing cleared and uncleared pastures across three different times since clearing (i.e. 5, 11–13 and 33 years since clearing) for the three dominant tree communities of central Queensland (i.e. Eucalyptus populnea F.Muell. (poplar box), E. melanophloia F.Muell. (silver-leaved ironbark) and Acacia harpophylla F.Muell. ex. Benth. (brigalow)). The results demonstrated that species diversity declined with clearing and sowing of exotic pastures. Species diversity and pasture production were negatively related. Although pasture yield was 2–3 times greater 13 years after clearing of E. populnea and A. harpohylla, the gains in pasture yield were not consistent over time, yields being only 1.5 times greater after 33 years of clearing. In E. melanophloia, an increase in the yield of only 1.5–1.8 times occurred 5 years after clearing compared with uncleared pastures, whereas 33 years after clearing, yield was 3/4 of that in uncleared pastures. The initial gains in pasture yield were accompanied by a loss of plant diversity that may affect ecosystem functions such as nutrient cycling or soil mineralisation, and the longer-term production gains.
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Sutherst, RW, ID Sutherland, AS Bourne, GF Maywald, and DA Stegeman. "Ecology of the cattle tick (Boophilus microplus) in subtropical Australia. I. Introduction and free-living stages." Australian Journal of Agricultural Research 39, no. 2 (1988): 285. http://dx.doi.org/10.1071/ar9880285.
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An experiment is described which compared the fluctuations in the numbers of cattle tick, Boophilus miicroplus, that resulted from direct climatic effects or from changes in host resistance. Four herds of cattle, matched for tick resistance and with different Bos indicus (zebu) content, were grazed at each of two locations, one in central Queensland (23� S.) and one in southern Queensland (28� S.), from November 1977 to May 1982. Natural tick populations were counted regularly, and host resistance was measured using artificial infestations, either twice or six times a year. Concurrent exposures of engorged ticks in pastures were used to measure the success of the ticks in producing larvae and to partition mortality during development. Two later papers report other aspccts of the experiment. These include observations on the resistance of cattle to ticks and on the relationship between tick numbers on the cattle on one hand, and the availability of larvae on pasture and survival of parasitic stages on the other. Engorged ticks produced more larvae throughout the year in central Queensland, despite laying fewer eggs. The colder and longer winter in southern Queensland greatly reduced tick reproduction. Failure of engorged ticks to survive predation and find a favourable oviposition site, egg mortality and loss of larvae in the pasture accounted for most of the reduction in the potential number of larvae produced. Reduced oviposition was also important in wintcr.
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Stone, G., B. Zhang, J. Carter, G. Fraser, G. Whish, C. Paton, and G. McKeon. "An online system for calculating and delivering long-term carrying capacity information for Queensland grazing properties. Part 1: background and development." Rangeland Journal 43, no. 3 (2021): 143. http://dx.doi.org/10.1071/rj20084.
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This paper (Part 1) describes the development of a new online system that estimates long-term carrying capacity (LTCC) for grazing properties across Queensland, Australia. High year-to-year and multi-year rainfall variability is a dominating feature of the climate of Queensland’s grazing lands, and poses major challenges for extensive livestock production. The use of LTCC is one approach used by graziers to reduce the impact of rainfall variability on land condition and financial performance. Over the past 30 years, scientists, graziers and their advisors have developed a simple approach to calculating LTCC ((average annual pasture growth × safe pasture utilisation) ÷ annual animal intake). This approach has been successful at a property scale (regional south-west Queensland) and in a wider application through Grazing Land Management (GLM) regional workshops. We have built on these experiences to develop an online system (as described in detail in Part 2; Zhang et al. 2021; this issue) that incorporates the simple LTCC approach with advances in technology and grazing science to provide LTCC information for Queensland grazing properties. Features of the LTCC system are: (1) assimilation of spatial datasets (cadastral data, grazing land types, climate data, remotely-sensed woody vegetation cover); (2) a pasture growth simulation model; (3) land type parameter sets of biophysical attributes; and (4) estimates of safe pasture utilisation. The ‘FORAGE LTCC report’ is a major product of the system, describing individual property information that allows detailed analysis and explanation of the components of the LTCC calculation by land type and land condition. The online system rapidly analyses property spatial data and calculates paddock/property LTCC information. For the 10 months between November 2020 and August 2021, over 4000 grazing property reports have been requested in Queensland, and has proven to be a sound basis for ‘discussion support’ with grazier managers and their advisors.
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Stone, G., R. Dalla Pozza, J. Carter, and G. McKeon. "Long Paddock: climate risk and grazing information for Australian rangelands and grazing communities." Rangeland Journal 41, no. 3 (2019): 225. http://dx.doi.org/10.1071/rj18036.
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The Queensland Government’s Long Paddock website has been redeveloped on Amazon Web Services cloud computing platform, to provide Australian rangelands and grazing communities (i.e. rural landholders, managers, pastoralists (graziers), researchers, advisors, students, consultants and extension providers) with easier access to seasonal climate and pasture condition information. The website provides free, tailored information and services to support management decisions to maximise productivity, while maintaining the natural resource base. For example, historical rainfall and pasture analyses (i.e. maps, posters and data) have been developed to assist in communicating the risk of multi-year droughts that are a feature of Queensland’s highly variable climate.
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Silcock, R. G., T. J. Hall, P. Jones, P. G. Filet, and J. Douglas. "Spring fire effects on two Aristida/Bothriochloa native pastures in central Queensland, Australia." Rangeland Journal 40, no. 5 (2018): 485. http://dx.doi.org/10.1071/rj17132.
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Controlled burns are commonly used to suppress woody plant regrowth and to remove accumulated unpalatable pasture from rangelands and occasionally to alter pasture composition in native pastures in central Queensland, Australia. Outcomes can be somewhat unpredictable and short-term, and reliable evidence is needed to confirm the likely long-term efficacy of such fires. We imposed a regime of repeated spring burns on native Aristida/Bothriochloa pastures growing in two contrasting eucalypt woodlands of central Queensland to determine the effects on pasture composition, ground cover, landscape stability and woody plant recruitment, all in the absence of grazing. The sites selected were a silver-leaved ironbark (Eucalyptus melanophloia F.Muell.) woodland and a poplar box (E. populnea F.Muell.) woodland. Weather conditions precluded spring burns in 3 years out of 7 at the silver-leaved ironbark site and in 2 years out of 8 at the poplar box site. The burn intensity was variable, and frequent fires produced a marked change in abundance of only a few pasture species. Depending on the site, fires significantly increased the frequency of Enneapogon spp., Bothriochloa bladhii (Retz.) S.T.Blake and Dichanthium sericeum (R.Br.) A.Camus and reduced the frequency of some minor components such as Cymbopogon spp., Panicum effusum R.Br., Cenchrus ciliaris L. and, ephemerally, that of some forbs. Contrary to expectation, only Aristida calycina R.Br. declined in abundance among the many Aristida species present, and the abundance of Heteropogon contortus (L.) P.Beauv. ex Roem. & Schult. barely increased under regular spring fires. The total germinable seeds of herbaceous species in the soil each spring was significantly reduced by burning in the previous spring. Repeated spring fires rarely reinforced any initial change induced by burning, and slightly lowered average ground cover as well as various indices of landscape stability and ecosystem functionality. Changes produced were not always consistent across the two communities. Though prescribed burning is often important for maintaining grazing productivity and landscape values, very regular use is not recommended.
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Zhang, B., G. Fraser, J. Carter, G. Stone, S. Irvine, G. Whish, J. Willcocks, and G. McKeon. "An online system for calculating and delivering long-term carrying capacity information for Queensland grazing properties. Part 2: modelling and outputs." Rangeland Journal 43, no. 3 (2021): 159. http://dx.doi.org/10.1071/rj20088.
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A combination of field data and models have been used to estimate long-term carrying capacity (LTCC) of domestic livestock in Queensland grazing lands. These methods have been synthesised and coupled with recent developments in science and information technology to provide a fully-automated approach of modelling LTCC through the FORAGE online system. In this study, the GRASP model was used to simulate pasture growth with parameter sets and safe pasture utilisation rates defined for 225 land types across Queensland. Distance to water points was used to assess the accessibility of pastures to livestock. Spatial analysis classified the property into unique areas based on paddock, land type and distance to water points, which estimated pasture growth, pasture utilisation and accessibility at a sub-paddock scale. Thirteen foliage projective cover (FPC) classes were used in modelling the pasture system to deal with the non-linear relationship between tree and grass interactions. As ‘proof of concept’, remotely-sensed individual-date green ground cover data were used to optimise the GRASP model parameters to improve the model performance, and a Monte Carlo analysis provided uncertainty estimates for model outcomes. The framework provides an efficient and standardised method for estimating LTCC. To test the system, LTCCs from 43 ‘benchmark’ properties were compared with simulated LTCCs, and 65% of the modelled LTCCs were within ± 25% of the benchmark LTCCs. Due to uncertainties in model inputs at the property scale and in model simulation, the modelled LTCC should be used as a starting point for further refinement of actual property LTCC.
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Stephenson, RGA, DA Pritchard, PM Pepper, and PT Connelly. "The effect of different pasture management strategies in north-west Queensland on liveweight gain and wool growth rate of several groups of young sheep." Rangeland Journal 7, no. 2 (1985): 75. http://dx.doi.org/10.1071/rj9850075.
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The effect of three different pasture management strategies on liveweight gain and wool growth rate of young(weaner) sheep was examined immediately after weaning on Mitchell grass-Flinders grass pastures during the dry season of north-west Queensland. The pasture management strategies were designed to mimic various industry situations, while the performance of four different progeny groups was compared and used to provide an overall assessment of pasture quality. Pasture treatments (experiment 1) consisted of three paddocks, a harvested (c. 8% of pasture harvested and baled) and spelled, a spelled, and a continuously grazed paddock. Spelled paddocks were not grazed during and after the wet season for a period of six months while the continuously grazed paddock was continuously stocked before the experiment. Experiment 2 consisted of spelled and continuously grazed paddocks. Pastures were evaluated by measuring the changes in composition and quality (experiment 1) and the responses in liveweight gain (experiments 1 and 2) and wool growth of the weaners (experiment 1). Marked improvements (c. 100%) in weaner growth rates occurred in the spelled paddocks. Greasy wool production by three groups of ewes in experiment I was about 14% greater in the harvested paddock than in the others. At the start of the trial there were no significant differences in dry matter yield but a significant difference in botanical composition occurred between paddocks. The changes in dry matter that occurred between the beginning and end of grazing were not significantly different between paddocks. Before gazing, forbs made up approximately 16%, 4% and 1% of pastures in harvested, spelled and continuously grazed paddocks respectively. The change in the percentage forbs that occurred between the beginning and end of the grazing period was significantly greater in the harvested paddock than in the other paddocks indicating preferential selection and intake by sheep. The differences in weaner live weight and wool growth between paddocks suggest that paddock management can improve weaner productivity. The study also indicates that paddock management could be successfully used to increase the percentage of forbs and quality of the pasture during the dry season. The superior wool growth of two progeny groups also suggests that improved productivity of breeding flocks in the tropics is possible if superior sheep can be identified. The results highlight the importance of preferential management of pasture for weaners so that productivity advantages can be exploited.
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Walsh, Dionne, and Robyn A. Cowley. "Looking back in time: can safe pasture utilisation rates be determined using commercial paddock data in the Northern Territory?" Rangeland Journal 33, no. 2 (2011): 131. http://dx.doi.org/10.1071/rj11003.
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A ‘safe’ pasture utilisation rate is defined as the proportion of annual forage growth that can be consumed by domestic livestock without adversely affecting land condition in the long term. Pasture utilisation rates are thus a cornerstone of a sustainable grazing industry because they directly determine livestock carrying capacity. Until now, it has only been possible to determine utilisation rates in the Northern Territory via expensive and time-consuming grazing trials. Reliance on this method has limited the validation of safe utilisation rates for the range of land types used for pastoral production. This study tested an alternative cost-effective method for calculating utilisation rates based on an approach used previously in Queensland. The method retrospectively calculates utilisation rates using cattle records and modelled pasture growth from commercial paddocks in good land condition. The assumption underpinning the method is that paddocks in good land condition, with a long history of grazing, must have been managed in such a way as to achieve a safe level of pasture utilisation. Utilisation rates were calculated for 10 commercial paddocks on three properties in the Barkly Tableland region of the Northern Territory from 1999 to 2009. Animal intake for each paddock was calculated from detailed cattle records held in property databases. Pasture growth was estimated using simulation models and cross-checked with field measurements. An average utilisation rate of up to 25% of annual pasture growth was found to be safe on highly uniform, grey cracking-clays supporting Mitchell grass (Astrebla F. Muell. spp.) pastures. However, this level of utilisation had negative impacts on land condition on less resilient and preferentially grazed pasture communities in paddocks with a mix of land types. The implications of the results for carrying capacity, animal productivity and seasonal risk management are explored in this paper.
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Fensham, RJ. "Native Grasslands of the Central Highlands, Queensland, Australia. Floristics, Regional Context and Conservation." Rangeland Journal 21, no. 1 (1999): 82. http://dx.doi.org/10.1071/rj9990082.
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A floristic classification of grassland and related woodland vegetation from the Central Highlands of Queensland suggests four broad types: Mountain coolibah (Eucalyptus orgadophila) woodland on basalt, Mitchell grassland (dominated by Astrebla lappacea) on alluvia and two closely related groups dominated by Dichanthium sericeum, Blue grassland on basalt and Blue grassland on sediment. An analysis including floristic data from grassland and woodland on vertosols from throughout southern, central and western Queensland revealed that the Blue grasslands of the Central Highlands are highly dissimilar from other grasslands in Queensland. Mountain coolibah woodland on basalt is represented within four reserves, but the other more arable grassland types are either not represented or only barely represented within the reserve system. The most immediate threatening process to these communities is conversion to crops and this process is exacerbated by the difficulties of managing the grasslands as native pasture. Large areas of grasslands are degraded, having been converted from dominance by native perennial grasses to the unpalatable, annual, exotic herb Partheniunz hysterophorus. Once this shift has occurred a long period with little or no production benefits is required to recover a sward of native perennial grasses and the cropping alternative becomes particularly favourable. The long-term security of the native grasslands of the Central Highlands will require an enhanced reserve system and incentives designed to retain appropriately managed native pasture. Key words: grassland, grazing, reserves, woodland. Queensland, exotics, Parthenium
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Coates, D. B., and R. M. Dixon. "Faecal near infrared reflectance spectroscopy (F.NIRS) measurements of non-grass proportions in the diet of cattle grazing tropical rangelands." Rangeland Journal 29, no. 1 (2007): 51. http://dx.doi.org/10.1071/rj07011.
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Frequent faecal near infrared reflectance spectroscopy (F.NIRS) analyses of faeces from cattle grazing a range of tropical pastures were used to measure the non-grass component, and other aspects, of their diets. Seasonal profiles of non-grass and crude protein in the diet are presented for nine sites from the speargrass, Aristida–Bothriochloa, and Mitchell grass dominated pasture regions, and for three shrubland sites where browse was plentiful. In grass-dominated native pastures of the speargrass and Aristida–Bothriochloa pasture regions of Queensland where little browse was available, non-grass was usually only 5–15% of the diet. Diet non-grass was even lower for a buffel grass pasture. In uncleared eucalypt woodland in the speargrass region, browse may have contributed up to 20% of the diet in the late dry season when grasses were senesced. In regions with abundant browse (e.g. mulga lands and desert upland systems) cattle preferentially selected actively growing grasses and forbs when they were available. With diminishing availability or declining quality of the forbs and grass due to grazing selection and dry conditions, browse increasingly contributed to intake. In Mitchell grass dominated pastures forbs often comprised more than 50% of the diet, and there appeared to be strong selection for forbs during the dry season. Where browse was available in association with Mitchell grass dominated pastures, it appeared to contribute to intake only in the late dry season. Dry season sampling in monsoonal tallgrass and Mitchell grass dominated pastures indicated dietary crude protein to be linearly correlated with diet non-grass, demonstrating the importance of non-grass in the prevention or alleviation of dry season protein deficiency in cattle. Changes in diet selected by cattle in relation to season and rainfall were generally in accord with the previous limited information, largely with sheep, in comparable vegetation systems. The results demonstrate the value of F.NIRS technology to assist understanding of diet selection by grazing cattle in northern Australia.
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Rolfe, J., R. Blamey, and J. Bennett. "Valuing the preservation of rangelands: Tree clearing in the desert uplands region of Queensland." Rangeland Journal 22, no. 2 (2000): 205. http://dx.doi.org/10.1071/rj0000205.
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Tree clearing to improve pasture production for beef cattle is becoming more commonplace in the rangeland zone in Queensland. In parts of the Desert Uplands region of Central Queensland, current clearing rates are among the highest in Australia. The state government, in granting permits for clearing, has to balance the improved production benefits, accruing mostly to pastoralists, against the biodiversity losses, which are borne more widely by Australian society. In the current debate over clearing restrictions, little information exists about the values that society may hold for the preservation of rangelands. To address this deficiency, a choice modelling study was undertaken to provide estimates of the benefits of retaining remnant vegetation that are appropriate for inclusion in a benefit cost analysis of tighter clearing restrictions. Attributes included in the choice model were reductions in the population size of non-threatened species and unique ecosystems, the number of endangered species lost to the region, and changes in regional income and employment. The benefits estimated for individual attributes, and for some more restrictive policy settings are reported. Key words: remnant native vegetation, economic valuation, grazing industry, pasture development, choice modelling
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Landsberg, RG, AJ Ash, RK Shepherd, and GM Mckeon. "Learning From History to Survive in the Future: Management Evolution on Trafalgar Station, North-East Queensland." Rangeland Journal 20, no. 1 (1998): 104. http://dx.doi.org/10.1071/rj9980104.
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Managing rangeland enterprises requires balancing socio-economic goals within a production environment characterised by ecological complexity and large climatic variability. Trafalgar Station in north-east Queensland, has been trying to maintain this balance over a period of 80 years and three generations of the one family. This paper explores how management on Trafalgar Station has gone through four evolutionary phases and examines the advantages and disadvantages of each of these stages of development. The first 50 years of management was a technologically constrained era of low stock numbers and poor productivity but there were few resource management problems. Next followed a 20 year period of production maximisation which was made possible by improved cattle genetics and nutritional technologies. With drought feeding occurring more frequently and loss of perennial grasses and soil becoming more evident, there came the realisation that this high stocking strategy was unsustainable. The management of Trafalgar then embarked on a new philosophy based on conservative stocking (similar to historical levels) and increased emphasis on herd, pasture and financial management. This new management philosophy required a transitional phase where stock numbers. and income, were very low to allow pasture condition to improve. Current herd management focuses on maintaining quality rather than quantity, strategic use of supplements for production, and developing a diverse range of markets for sale cattle. Conservative stock numbers have increased opportunities in pasture management with 15 to 20% of the property now annually rested from grazing. Fire has been reintroduced to restrict "thickening" of native woody plants and to control exotic woody weeds. Together with long-term financial planning, these improvements in management are reducing economic risk. The perceived benefits of the current management philosophy are supported by simulation modelling studies of pasture and animal production and analyses of property economics.
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Bebawi, Faiz F., Shane D. Campbell, and Robert J. Mayer. "Can competition with pasture be used to manipulate bellyache bush (Jatropha gossypiifolia L.) population biology?" Rangeland Journal 35, no. 4 (2013): 393. http://dx.doi.org/10.1071/rj13011.
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Bellyache bush (Jatropha gossypiifolia L.) is an invasive weed that poses economic and environmental problems in northern Australia. Competition between pasture and bellyache bush was examined in North Queensland using combinations of five pasture treatments (uncut (control); cut as low, medium, and high pasture; and no pasture) and four bellyache bush densities (0, 2, 6 and 12 plants m−2) in a buffel grass (Cenchrus ciliaris L.) dominated pasture. The pasture treatments were applied approximately once per year but no treatments were applied directly to the bellyache bush plants. Measurements of bellyache bush flowering, seed formation, and mortality were undertaken over a 9-year period, along with monitoring the pasture basal cover and plant species diversity. Maximum flowering rates of bellyache bush occurred after 9 years (97%) in plots containing no pasture, with the lowest rates of 9% in uncut control plots. Earliest flowering (322 days after planting) and seed formation (411 days) also occurred in plots with no pasture compared with all other pasture treatments (range 1314–1393 days for seed formation to occur). No seeds were produced in uncut plots. At the end of 9 years, mortality rates of bellyache bush plants initially planted averaged ≥73% for treatments with some pasture compared with 55% under the no-pasture treatment. The percentage of herbaceous plant basal cover in uncut plots was increased 5-fold after 9 years, much greater than the average 2% increase recorded across the low, medium, and high pasture treatments. The number of herbaceous species in uncut plots remained largely unchanged, whereas there was an average reduction of 46% in the cut pasture treatments. Buffel grass remained the species with the greatest basal cover across all cut pasture treatments, followed by sabi grass (Urochloa mosambicensis (Hack.) Dandy) and then red Natal grass (Melinis repens (Willd.) Ziska). These results suggest that grazing strategies that maintain a healthy and competitive pasture layer may contribute to reducing the rate of spread of bellyache bush and complement traditional control techniques such as the use of herbicides.
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Macleod, ND, and S. Mcintyre. "Stocking Rate Impacts on the Production and Economic Performance of Steers Grazing Black Speargrass Pastures." Rangeland Journal 19, no. 2 (1997): 174. http://dx.doi.org/10.1071/rj9970174.
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A grazing trial conducted in subtropical Queensland examined the effect of four stocking rates (high, medium, low, very low) on beef production, economic returns and pasture stability. Liveweight gains of steers were recorded in legume sown pastures, over a five year period in which severe drought conditions prevailed. Although high stocking rates generated the highest levels of beef production per hectare, moderate rates generated the highest economic returns. The status of the dominant perennial tussock grass (Heteropogon contortus) was used as an indicator of pasture condition. While H, contortus declined in all treatments during the drought, populations were most persistent at the low stocking rate. The results provide clear evidence of a trade-off between ecologically optimal stocking rates and animal production. The highest net profit was derived from the medium stocking rate, which was more than 50% higher than the next most profitable stocking rate. However, at this stocking rate there was evidence of a decline in the dominant grass, H. contortus, which suggests that the medium stocking rate may not be sustainable over the long-term. The highest stocking rate paddocks all required supplementary feeding of stock and were poor both in economic return and ecological condition. The low stocking rate plots had the highest rates of liveweight gain per animal and had low ecological risk, but had low to negative returns on equity and were not sustainable economically. Key words: - stocking rates, black speargrass pastures, economics, range condition, drought.
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Scanlan, J. C. "Some aspects of tree-grass dynamics in Queensland's grazing lands." Rangeland Journal 24, no. 1 (2002): 56. http://dx.doi.org/10.1071/rj02003.
Full textAbstract:
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.
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Balston, Jacqueline, and Bernie English. "Defining and predicting the 'break of the season' for north-east Queensland grazing areas." Rangeland Journal 31, no. 1 (2009): 151. http://dx.doi.org/10.1071/rj08054.
Full textAbstract:
For pasture growth in the semi-arid tropics of north-east Australia, where up to 80% of annual rainfall occurs between December and March, the timing and distribution of rainfall events is often more important than the total amount. In particular, the timing of the ‘green break of the season’ (GBOS) at the end of the dry season, when new pasture growth becomes available as forage and a live-weight gain is measured in cattle, affects several important management decisions that prevent overgrazing and pasture degradation. Currently, beef producers in the region use a GBOS rule based on rainfall (e.g. 40 mm of rain over three days by 1 December) to define the event and make their management decisions. A survey of 16 beef producers in north-east Queensland shows three quarters of respondents use a rainfall amount that occurs in only half or less than half of all years at their location. In addition, only half the producers expect the GBOS to occur within two weeks of the median date calculated by the CSIRO plant growth days model GRIM. This result suggests that in the producer rules, either the rainfall quantity or the period of time over which the rain is expected, is unrealistic. Despite only 37% of beef producers indicating that they use a southern oscillation index (SOI) forecast in their decisions, cross validated LEPS (linear error in probability space) analyses showed both the average 3 month July–September SOI and the 2 month August–September SOI have significant forecast skill in predicting the probability of both the amount of wet season rainfall and the timing of the GBOS. The communication and implementation of a rigorous and realistic definition of the GBOS, and the likely impacts of anthropogenic climate change on the region are discussed in the context of the sustainable management of northern Australian rangelands.
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Pressland, AJ, and DC Cowan. "Response of plant growth to removal of surface soil of the rangelands of western Queensland." Rangeland Journal 9, no. 2 (1987): 74. http://dx.doi.org/10.1071/rj9870074.
Full textAbstract:
Pot and field studies were conducted to determine the potential effect on plant production of soil erosion in western Queensland. Soil from both the Mitchell grass (Astrebla spp.) and mulga (Acacin aneura) woodlands were used, but the studies concentrated on the latter soils. Test plants (oats, sorghum and pasture grass species) were grown in soil taken from sequential 5 cm intervals from the surface to 20 cm down the profile of each of the selected soils. Plants growing in subsurface soil, irrespective of soil type or history, were less productive than those growing on surface soil. This was attributed in part to reduced soil fertility and a difference in soil pH. Buffel grass (Cenchrur ciliaris), a species which has some use as an improved pasture in these rangelands, would be seriously disadvantaged on eroded soils. It is concluded that erosion of surface soil on these landscapes should be minimized by conserving ground cover.
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Scanlan, JC, AJ Pressland, and DJ Myles. "Grazing Modifies Woody and Herbaceous Components of North Queensland Woodlands." Rangeland Journal 18, no. 1 (1996): 47. http://dx.doi.org/10.1071/rj9960047.
Full textAbstract:
Grazed and exclosed areas within north Queensland woodlands were studied over a six-year period which included a drought followed by an above average rainfall period. Despite drought conditions, woody plant density increased, with exclosed areas showing a greater increase than grazed areas. During the drought period, a pattern of herbaceous vegetation strips interspersed with bare areas developed. Standing dry matter and ground cover increased rapidly in response to above average rainfall following the drought. Also, the pattern of strips became less apparent during the more favourable growth conditions. The percentage contribution of native tussock grasses (principally Heteropogon contortus) to total pasture dry matter varied to a greater extent over the six-year period than the naturalised stoloniferous Bothriochloa pertusa.
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McMeniman, NP, IF Beale, and G. Payne. "The nutrient status of sheep grazing on a dry Mitchell grass pasture association in central-western Queensland." Rangeland Journal 11, no. 1 (1989): 7. http://dx.doi.org/10.1071/rj9890007.
Full textAbstract:
The lambing performance of a group of ewes grazing a dry Mitchell grass pasture association in central-westem Queensland was recorded and found to be very poor. A portion of the ewe flock received a urea-molasses supplement those ewes did not exhibit an increase in lamb or ewe survival and it is likely that most did not consume the supplement. One week prior to the ewes' expected date of lambing, intact wethers and other wethers with oesophageal fistulas or rumen and abomasal cannulas were grazed on the pasture and the intake and digestion of nutrients by these animals were determined. Extrapolating the results from the wethers to the ewes indicated that the major limiting nutrients for the ewes were energy and, at least during the latter stages of lactation, rumen digestible nitrogen. Other nutrients that may have been deficient in the diet were copper and zinc.
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Fleet, Graham H., and Graham H. Fleet. "Biodiversity and ecology of Australasian yeasts (fungi)." Australian Systematic Botany 14, no. 3 (2001): 501. http://dx.doi.org/10.1071/sb00017.
Full textAbstract:
The biodiversity and ecology of yeasts associated with natural habitats have attracted little systematic research in Australasia. Most isolations concern yeasts associated with foods and beverages such as wine, fruit juices, soft drinks, dairy products, high-sugar products and processed meats. Although these yeasts have interesting physiological and biochemical properties (e.g. xerotolerance, preservative resistance, protease and lipase activity), they are similar to species found in products in other countries. Ecological studies of yeasts associated with cactus, hibiscus, morning glory plants and associated insects of New South Wales and Queensland have revealed new species including Pichia opuntiae, Clavispora opuntiae, and Wickerhamiella australiensis, Kodamaea anthophila, Kodamaea kakaduensis, Metschnikowia hibisciand a unique predacious species of Candida. New species of Cryptococcus and Rhodotorula were isolated from soils and pasture grasses in New Zealand. Clinical isolates in the genera Candida and Cryptococcus are similar to those found overseas but Cryptococcus neoformans var. gattii is uniquely associated with the red gum tree, Eucalyptus camaldulensis.
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Kutt, Alex S., and Alaric Fisher. "Increased grazing and dominance of an exotic pasture (Bothriochloa pertusa) affects vertebrate fauna species composition, abundance and habitat in savanna woodland." Rangeland Journal 33, no. 1 (2011): 49. http://dx.doi.org/10.1071/rj10065.
Full textAbstract:
The invasion of exotic pasture species into intact woodlands has the potential to affect native fauna by altering habitat structure and ecosystem function. The spread of these weeds is generally in concert with cattle grazing, so that fauna or habitat change is due to multiple interrelated causes. In this study we investigated whether the spread of the introduced pasture grass Bothriochloa pertusa and replacement of the native bluegrass B. ewartiana in eucalypt woodlands of northern Queensland has had an effect on terrestrial vertebrate fauna. We located 40 sites that sampled a range of native and introduced pastures cover, and investigated the spatial pattern of abundance with canonical analysis of principle coordinates, and correlation of the habitat attributes on the ordination space. We then selected a subset of four habitat attributes (eliminating highly colinear variables) and modelled species response to each using an information-theoretic approach. Thirty-one species (26 birds, one mammal and four reptiles) and two summary variables (bird abundance and richness) had best subset Akaike Information Criteria models with reliable parameters estimates. Seventeen models contained the B. pertusa frequency term and a further 16 had a term relating to upper storey cover (tree cover >10, 5–10 or 3–5 m). Though pasture grass cover, grazing and habitat features were correlated and thus we cannot ascribe B. pertusa as the sole determinant of fauna species change, this study has demonstrated that tropical savanna woodlands with changing Bothriochloa dominance from native to introduced species have different fauna species composition. In particular bird species richness, ground nesting species (e.g. rufous songlark Cincloramphus mathewsi, golden-headed cisticola Cisticola exilis) and terrestrial reptiles (e.g. Carlia munda and Ctenotus taeniolatus) declined. Disturbance-tolerant species such as Australian magpie Cracticus tibicen and yellow-throated miners Manorina flavigula increased in abundance in exotic pasture-dominated sites. As pastoral intensification continues in northern Australian rangelands there is a potential for significant change in the relative abundance and composition of vertebrate fauna and the reduction or loss of some species in the landscape.
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Oxley, RE. "Analysis of historical records of a grazing property in south-western Queensland. 1. Aspects of the patterns of development and productivity." Rangeland Journal 9, no. 1 (1987): 21. http://dx.doi.org/10.1071/rj9870021.
Full textAbstract:
This article examines historical records of a grazing property in south-westem Queensland to analyse various aspects of station improvements, pasture and sheep productivity. The drought at about the turn of the century was the catalyst that led to a permanent loss of pasture and canying capacity. Competition from rabbits and the full utilisation of grazing land by about 1914 exacerbated the situation. The station was able to cope with early localised degradation because new land was constantly becoming available due to improvements in fencing and stock watering facilities. Summer rainfall was of utmost importance in providing sufficient perennial grass for the maintenance of stock numbers. Annual sheep losses and average fleece weights were highly correlated with the amount of summer rainfall. A high lambing percentage was dependent on good seasonal conditions-over the 18 months.
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Brown, RF. "The effects of burning, fertilizing and clipping on populations of Aristida armata, Thyridolepis mitchelliana and Monachather paradoxa in a mulga woodland pasture." Rangeland Journal 8, no. 1 (1986): 4. http://dx.doi.org/10.1071/rj9860004.
Full textAbstract:
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.
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Sangha, Kamaljit K., David J. Midmore, John Rolfe, and Rajesh K. Jalota. "Tradeoffs between pasture production and plant diversity and soil health attributes of pasture systems of central Queensland, Australia." Agriculture, Ecosystems & Environment 111, no. 1-4 (December 2005): 93–103. http://dx.doi.org/10.1016/j.agee.2005.05.007.
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Thompson, J., J. Riethmuller, D. Kelly, E. Miller, and J. C. Scanlan. "Feral goats in south-western Queensland: a permanent component of the grazing lands." Rangeland Journal 24, no. 2 (2002): 268. http://dx.doi.org/10.1071/rj02015.
Full textAbstract:
Feral goats were harvested in south-western Queensland at four sites under two regimes (opportunistic harvesting and sustained control). We assessed how this impacted on their contribution to total grazing pressure, on soil and pasture conditions and on the economics of goat management. The population impact was not consistent across sites with the same treatment, with 62% and 84% reductions in numbers in the two northern sites (one opportunistic harvesting site and one sustained control site) while numbers in the southern sites essentially remained the same. The contribution of goats to grazing pressure ranged from 3 to 30%; kangaroos contributed 16–36%; and livestock contributed 37–72%. Harvest rates of feral goats calculated for each of the sites ranged from 17 to 41%. There was no consistent relationship between population changes and the harvest rates. Seasonal conditions had greater influence on pasture and soil conditions than did changes in feral goat populations. The average cost of mustering goats (based on 34 operations) was $1.93 per head. Mustering costs increased markedly when goat density was lower than 10/km2. Average trapping costs (based on 7 trapping programs) were $2.08 per head. This compared with on-farm prices of $16–$25 per head in 1997. Personal circumstances and preferences of individual landholders were the key determinant of the level of control undertaken. Variability in price contributed to landholders being apprehensive about the viability of the goat industry. There are few simple tools available for landholders to estimate feral goat numbers and this makes effective management of total grazing pressure difficult.
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Bebawi, Faiz F., Shane D. Campbell, and Robert J. Mayer. "Seed ecology of Captain Cook tree [Cascabela thevetia (L.) Lippold] – germination and longevity." Rangeland Journal 39, no. 4 (2017): 307. http://dx.doi.org/10.1071/rj17025.
Full textAbstract:
Cascabela thevetia (L.) Lippold (Apocynaceae), commonly known as Captain Cook tree or yellow oleander, has established large infestations in riparian areas along several creeks and rivers in northern Queensland. To better understand the ecology of C. thevetia and the implications for its spread and management, this study reports seven experiments related to the seed ecology of its yellow and peach biotypes. We quantified its germination response to ambient (Experiment 1a and 1b), alternating and constant temperature (Experiment 2a and 2b) regimes and exposure to different light conditions (Experiment 3). Seed longevity under two soil types, two levels of pasture cover and three burial depths was also determined (Experiment 4a and 4b). Both loose seeds and seeds still within pods (kernels) of the two biotypes of C. thevetia were able to germinate in all months of the year in northern Queensland, irrespective of the large differences in monthly ambient temperatures experienced at the Charters Towers study site. Both biotypes also germinated across a wide range of alternating day/night temperatures from 16/12°C to 47/37°C and constant temperatures from 17°C to 44.0°C. Germination of the two biotypes was significantly greater (4-fold) and faster (7 days earlier) under shade than under natural light conditions. Over all biotypes, soil types, levels of pasture cover and burial depths, no seeds of C. thevetia remained viable after 2 years: longevity was much less in many circumstances. The results demonstrate that C. thevetia seeds can germinate over a wide temperature range, whereas the ability of seed to remain viable at low temperatures highlights the potential for expansion of its current potential distribution towards southern latitudes of the Australian continent. Across all experimental conditions, the yellow biotype displayed superior seed germination and viability traits compared with the peach biotype. Seed banks of the peach and yellow biotypes of C. thevetia are short-lived (2 years), which may be exploited when developing management strategies to reduce its impacts.
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Laurance, WF, J. Garesche, and CW Payne. "Avian nest predation in modified and natural habitats in troprical Queensland: an exeperimental study." Wildlife Research 20, no. 6 (1993): 711. http://dx.doi.org/10.1071/wr9930711.
Full textAbstract:
Predation on artificial avian ground-nests was assessed from March to December 1991 in rainforest and nearby modified habitats in tropical Queensland. Data from 610 experimental nests were used to determine relative predation intensity in five types of habitat or microhabitat. Nest predators were identified with live-traps, with baited grease-plates and by regular observations of 380 additional nests. Predation intensity was patchy but often heavy in forested habitats (rainforest interiors, secondary forest, rainforest-pasture edges, and a rainforest-secondary forest edge) and negligible in adjoining cattle pastures. Forest edges exhibited no obvious edge-interior gradients in predation intensity. Most predation occurred at night in rainforest (88%) and secondary forest (61%), and patterns of egg damage suggested that mammals were responsible for most (>71%) nest predation. A combined nest-predation and live-trapping experiment on six study plots revealed that the abundance of white-tailed rats (Uromys caudimaculatus) was a highly effective predictor of local predation intensity (F=30.15, r*2=0.85, P=0.004). One of Australia's largest rodents, the white-tailed rat may be a key opportunistic predator of some bird nests in north Queensland rainforest.
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Ludwig, J., and D. Tongway. "Clearing savannas for use as rangelands in Queensland: altered landscapes and water-erosion processes." Rangeland Journal 24, no. 1 (2002): 83. http://dx.doi.org/10.1071/rj02004.
Full textAbstract:
This paper presents a framework and some examples of how tree clearing alters landscapes (vegetation structure and faunal habitat) and processes (run-off and soil erosion) for eucalypt savannas in Queensland. Unaltered savannas have a tree-layer and a well-covered ground-layer of perennial grasses, and they provide habitats favoured by a variety of open woodland birds, reptiles and small mammals. Because unaltered savannas have a high ground-cover, they have low rates of run-off and erosion. When savannas are chained, but otherwise unaltered, trees rapidly regrow and increase in canopy cover. The exotic buffel grass often establishes in chained regrowth (especially if grazed), although the cover of native grasses such as black speargrass remains high (unless heavily grazed). We found that open woodland birds declined on these chained regrowth sites, except for the Weebill, which increased in abundance. When savannas are cleared of trees and woody debris and developed as improved pasture systems, both exotic and native perennial grass increased in cover. However, open woodland fauna abundance declined whereas grassland fauna such as the Red-backed Fairy-wren and the House Mouse increased in abundance. If these pasture sites are heavily utilised by livestock so that ground-cover is reduced, rates of run-off and soil loss are likely to rapidly increase, especially as cover declines below 40%. These run-off and erosion findings suggest that the manner in which savanna landscapes are cleared and subsequently used will have flow-on effects at catchment scales.
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Schmidt, Susanne, and Rebecca E. Lamblea. "Nutrient dynamics in Queensland savannas: implications for the sustainability of land clearing for pasture production." Rangeland Journal 24, no. 1 (2002): 96. http://dx.doi.org/10.1071/rj02005.
Full textAbstract:
Eucalyptus savannas on low nutrient soils are being extensively cleared in Queensland. In this paper we provide background information relevant to understanding nutrient (particularly nitrogen) dynamics in sub/tropical savanna, and review the available evidence relevant to understanding the potential impact of clearing Eucalyptus savanna on nutrient relations. The limited evidence presently available can be used to argue for the extreme positions that: (i) woody vegetation competes with grasses for resources, and tree/shrub clearing improves pasture production, (ii) woody vegetation benefits pasture production. At present, the lack of fundamental knowledge about Australian savanna nutrient relations makes accurate predictions about medium- and long-term effects of clearing on nutrient relations in low nutrient savannas difficult. The future of cleared savannas will differ if herbaceous species maintain all functions that woody vegetation has previously held, or if woody species have functions distinct from those of herbaceous vegetation. Research suggests that savanna soils are susceptible to nitrate leaching, and that trees improve the nutrient status of savanna soils in some situations. The nitrogen capital of cleared savanna is at risk if mobile ions are not captured efficiently by the vegetation, and nitrogen input via N2 fixation from vegetation and microbiotic crusts is reduced. In order to predict clearing effects on savanna nutrient relations, research should be directed to answering (i) how open or closed nutrient cycles are in natural and cleared savanna, (ii) which functions are performed by savanna constituents such as woody and herbaceous vegetation, native and exotic plant species, termites, and microbiotic crusts in relation to nutrient cycles. In the absence of detailed knowledge about savanna functioning, clearing carries the risk of promoting continuous nutrient depletion.
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Mcivor, John G., Andrew J. Ash, and Garry D. Cook. "Land Condition in the Tropical Tallgrass Pasture Lands. 1. Effects on Herbage Production." Rangeland Journal 17, no. 1 (1995): 69. http://dx.doi.org/10.1071/rj9950069.
Full textAbstract:
A quantitative condition index based on vegetation (botanical composition and basal area of perennial grasses) and soil characteristics (erodibility, nutrient status and availability, partitioning of rainfall into infiltration and run-off) was developed for tropical tallgrass pastures near Charters Towers (north-east Queensland) and Katherine (Northern Territory). Herbage growth and the responses of individual species at 10 sites over two growing seasons were related to the index. At all sites there were significant linear relationships between herbage growth and condition index although the values differed between sites. Annual grasses increased and most perennial grasses decreased as condition declined but Bothriochloa pertusa and Bothriochloa ewartiana were most abundant at intermediate condition levels. The response of Chrysopogon fallax varied widely between sites. The lower herbage production on poor condition sites will result in lower carrying capacity.
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Roe, R., and GH Allen. "Studies on the Mitchell Grass Association in South-Western Queensland. 3. Pasture and Wool Production Under Different Rates of Stocking and Continuous or Rotational Grazing." Rangeland Journal 15, no. 2 (1993): 302. http://dx.doi.org/10.1071/rj9930302.
Full textAbstract:
Pasture productivity and wool production on the Warrego Mitchell grass (Astrebla spp.) rangeland in south-westem Queensland were studied over a period of 13 years under continuous or rotational grazing, each at three stocking rates. The stocking rates were one sheep to three, two or one hectares and the rotational grazing was a six- monthly system of summer or winter grazing. The grazing treatments were applied over two five- year terms with a nil-grazing period at the conclusion of each. The latter periods provided a means of measuring the cumulative effects of the grazing treatments. Drought conditions prevailed during the first term so that supplementary feeding was necessary, but the second experienced above average rainfall. Quarterly measurements were made of the pasture dry matter on offer and its botanical and chemical composition. Monthly sheep liveweights, annual wool production and sheep size development in each term were also measured and monetary returns from wool calculated. Rainfall had a major influence on the results recorded and tended to nullify the effects of grazing treatments. Its unpredictability precludes the reliable use of complex techniques in management planning. The overall results suggested that the optimum grazing management of this Mitchell grass rangeland would be continuous grazing at a stocking rate of one sheep to two hectares. Supplementary feeding during drought would be obligatory and should be budgeted for in long-term planning. There was a 50% higher monetary return from this grazing treatment than from the lighter stocking rate and pasture stability (maintenance of Astrebla spp.) was sustained. Pasture stability was adversely affected by the heavier stocking rate. There was no srlstained advantage from rotational grazing compared with continuous grazing.
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Watter, Kurt, Greg S. Baxter, Anthony Pople, and Peter J. Murray. "Dietary overlap between cattle and chital in the Queensland dry tropics." Rangeland Journal 42, no. 3 (2020): 221. http://dx.doi.org/10.1071/rj20075.
Full textAbstract:
Chital deer (Axis axis) are an ungulate species introduced to northern Queensland, Australia, in an environment where land is managed for large scale cattle production. Rainfall and pasture growth are markedly seasonal and cattle experience a nutritional shortfall each year before monsoon rain. The presence of chital is perceived by land managers to reduce dry-season grass availability and this study sought to estimate the potential effect of free-living chital on regional cattle production. Diet overlap was greatest during the wet season when both ungulates principally consumed grass, and least during the dry season when chital diet comprised only ~50% grass. Using local estimates for energy values of wet and dry season grass, and the maintenance energy requirements of chital and cattle, we estimated the relative dry-matter seasonal grass intakes of both ungulates. The grass consumed annually by 100 chital could support an additional 25 cattle during the wet season and an additional 14 cattle during the dry season.
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Henry, B. K., T. Danaher, G. M. McKeon, and W. H. Burrows. "A review of the potential role of greenhouse gas abatement in native vegetation management in Queensland's rangelands." Rangeland Journal 24, no. 1 (2002): 112. http://dx.doi.org/10.1071/rj02006.
Full textAbstract:
Concern about the risk of harmful human-induced climate change has resulted in international efforts to reduce greenhouse gas emissions to the atmosphere. We review the international and national context for consideration of greenhouse abatement in native vegetation management and discuss potential options in Queensland. Queensland has large areas of productive or potentially productive land with native woody vegetation cover with approximately 76 million ha with woody cover remaining in 1991. High rates of tree clearing, predominantly to increase pasture productivity, continued throughout the 1990s with an average 345,000 ha/a estimated to have been cleared, including non-remnant (woody regrowth) as well as remnant vegetation. Estimates of greenhouse gas emissions associated with land clearing currently have a high uncertainty but clearing was reported to contribute a significant proportion of Australia's total greenhouse gas emissions from 1990 (21%) to 1999 (13%). In Queensland, greenhouse emissions from land clearing were estimated to have been 54.5 Mt CO2-e in 1999. Management of native vegetation for timber harvesting and the proliferation of woody vegetation (vegetation thickening) in the grazed woodlands also represent large carbon fluxes. Forestry (plantations and native forests) in Queensland was reported to be a 4.4 Mt CO2-e sink in 1999 but there are a lack of comprehensive data on timber harvesting in private hardwood forests. Vegetation thickening is reported for large areas of the c. 60 million ha grazed woodlands in Queensland. The magnitude of the carbon sink in 27 million ha grazed eucalypt woodlands has been estimated to be 66 Mt CO2-e/a but this sink is not currently included in Australia's inventory of anthropogenic greenhouse emissions. Improved understanding of the function and dynamics of natural and managed ecosystems is required to support management of native vegetation to preserve and enhance carbon stocks for greenhouse benefits while meeting objectives of sustainable and productive management and biodiversity protection.
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McIvor, J. G., I. Saeli, J. J. Hodgkinson, and H. M. Shelton. "Germinable soil seedbanks in native pastures near Crows Nest, south-east Queensland." Rangeland Journal 26, no. 1 (2004): 72. http://dx.doi.org/10.1071/rj04005.
Full textAbstract:
The soil seedbanks in three patch types (tall grassland, short sward and lawn) were measured in native pastures near Crows Nest, south-east Queensland in two experiments. In the first experiment, seedbanks were measured at four sites, and in the second, the variation in seedbanks during the year was measured at one site. In each experiment the size and composition of the seedbanks were determined by germinating the seeds in soil samples. In the first experiment, total seed numbers ranged from ~6000 to 12,000 per m2. There were no significant differences between sites for total seeds or for seeds of any species group except legumes which comprised only a small portion of the seedbanks. There were significant differences between patch types for total seeds and for the following species groups, medium tussock grasses, short tussock grasses, stoloniferous grasses, legumes and forbs but not large tussock grasses and sedges. Total seed numbers, and those of medium tussock grasses, stoloniferous grasses and forbs were highest in the lawn patches and lowest in the short sward patches. Legumes had higher numbers in the tall grassland patches than in other patch types. In the second experiment, there were large differences between total seed numbers at the different sample dates (January, May, September and November). Numbers were highest in January and then declined throughout the year. This pattern was largely a reflection of the changes in numbers of forb seeds, the species group with the most seeds. There were no significant differences between patch types for total seeds but there were for medium tussock grasses, stoloniferous grasses, sedges and forbs. There was no relationship between the composition of the pasture sward and the composition of the seedbank for any of the three patch types. Twenty-eight species were allocated to persistent and transient seedbank types; all seedbank types occurred in all three patch types. The major species in the seedbanks were sedges (Cyperus gracilis, C. sesquiflorus), forbs (Gamochaeta spp., Paronychia brasiliana, Daucus glochidiatus) and Eragrostis spp.
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Lucas, RM, AK Milne, N. Cronin, C. Witte, and R. Denham. "The potential of synthetic aperture radar (SAR) for quantifying the biomass of Australia's woodlands." Rangeland Journal 22, no. 1 (2000): 124. http://dx.doi.org/10.1071/rj0000124.
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The potential of Synthetic Aperture Radar (SAR) for estimating the above ground and component biomass of woodlands in Australia is demonstrated using two case studies. Case Study 1 (In,june; central Queensland) shows that JERS-1 SAR L HH data can be related more to the trunk than the leaf and branch biomass of woodlands. A strong relationship between L HH and above ground biomass is obtained when low biomass pasture sites are included. Case Study I1 (Talwood, southern Queensland) determines that L and P band data can be related both to trunk and branch biomass, due to the similarity in the orientation and size of these scattering elements, and also to total above ground biomass. Saturation of the C. L and P band data occurred at approximately 20-30 Mglha; 60-80 Mglha and 80-100 Mglha. These preliminary results indicate that data from SAR are useful for quantifying changes in carbon stocks resulting from land use change in Australia's woodlands and for applications in rangeland assessment and management. Key words: remote sensing, biomass, woodlands
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Mcalpine, CA, GC Grigg, JJ Mott, and P. Sharma. "Influence of Landscape Structure on Kangaroo Abundance in a Disturbed Semi-Arid Woodland of Queensland." Rangeland Journal 21, no. 1 (1999): 104. http://dx.doi.org/10.1071/rj9990104.
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This paper develops a hierarchical landscape approach for investigating how landscape structure influences the abundance of eastern grey kangaroos, red kangaroos and common wallaroos on properties in a partially cleared semi-arid woodland of Queensland. This approach is applied to examine the extent to which a mosaic of spatial factors at a hierarchy of scales influences kangaroo abundance at the property level. the level of management interest. The analysis concludes that the structure of the property habitat mosaic, coupled with pasture productivity, is the most important influence for each species. Access to water was not a limiting factor. although it may be important locally. Grey kangaroos prefer an even mosaic of all habitat types on properties with productive grass-dominated pastures. Red kangaroos are positively associated with run-on areas and large-shrub regrowth patches. reflecting their foraging preferences for forbs and short grasses and their ability to use more open habitats. Wallaroos have a clumped density distribution associated with a heterogeneous mosaic of open habitats interspersed with fragmented forest patches and small to medium-grained shrub-regrowth patches. The research. \+bile not replicated. identifies linkages between tree clearing practices at the property level and increased large kangaroo abundance in the region, These linkages have been previously overlooked in thc kangaroo Inanagement debare. Therefore. any tree clearing guidelines dt.\eloped at the propert) level need to be sensitive to key ecological processes influencing kangaroo populations at both the landscape and property levels. If not, the sustainable management of total grazing pressure (livestock plus kangaroos) and biodiversity conservation will never become a reality. Key words: kangaroos, landscape structure, landscape change, pattern, process, scale
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Silcock, RG, LM Williams, and F. Smith. "Quality and storage characteristics of the seeds of important native pasture species in South-West Queensland." Rangeland Journal 12, no. 1 (1990): 14. http://dx.doi.org/10.1071/rj9900014.
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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.
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Shi, Boyang, Olusegun O. Osunkoya, Aakansha Chadha, Singarayer K. Florentine, and Kunjithapatham Dhileepan. "Biology, Ecology and Management of the Invasive Navua Sedge (Cyperus aromaticus)—A Global Review." Plants 10, no. 9 (September 7, 2021): 1851. http://dx.doi.org/10.3390/plants10091851.
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Navua sedge (Cyperus aromaticus (Ridley) Mattf. & Kukenth) is an invasive perennial sedge, native to tropical Africa, which is threatening many natural ecosystems and agroecosystems, especially in northern Queensland, Australia. Crop and pasture production have been impacted by Navua sedge and it is also directly causing reductions in dairy and beef production in affected regions. This review documents the biology, ecology and potential management options to minimise the spread and impact of Navua sedge. The weed reproduces both sexually (seeds) and vegetatively (via underground rhizomes). Its tiny seeds can be spread easily via wind, water, vehicles, farm machinery and animals, whilst the rhizomes assist with establishment of dense stands. The CLIMEX model (which uses distribution and climate data in native and novel ranges) indicates that in Australia, Navua sedge has the potential to spread further within Queensland and into the Northern Territory, New South Wales and Victoria. Several management strategies, including mechanical, chemical and agronomic methods, and their integration will have to be used to minimise agricultural production losses caused by Navua sedge, but most of these methods are currently either ineffective or uneconomical when used alone. Other management approaches, including biological control and mycoherbicides, are currently being explored. We conclude that a better understanding of the interaction of its physiological processes, ecological patterns and genetic diversity across a range of conditions found in the invaded and native habitats will help to contribute to and provide more effective integrated management approaches for Navua sedge.
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Hall, WB, GM Mckeon, JO Carter, KA Day, SM Howden, JC Scanlan, PW Johnston, and WH Burrows. "Climate Change in Queensland's Grazing Lands: Ii. An Assessment of the Impact on Animal Production From Native Pastures." Rangeland Journal 20, no. 2 (1998): 177. http://dx.doi.org/10.1071/rj9980177.
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The 160 million ha of grazing land in Queensland support approximately 10 million beef equivalents (9.8 million cattle and 10.7 million sheep) with treed and cleared native pastures as the major forage source. The complexity of these biophysical systems and their interaction with pasture and stock management, economic and social forces limits our ability to easily calculate the impact of climate change scenarios. We report the application of a systems approach in simulating the flow of plant dry matter and utilisation of forage by animals. Our review of available models highlighted the lack of suitable mechanistic models and the potential role of simple empirical relationships of utilisation and animal production derived from climatic and soil indices. Plausible climate change scenarios were evaluated by using a factorial of rainfall (f 10%) * 3260C temperature increase * doubling CO, in sensitivity studies at property, regional and State scales. Simulation of beef cattle liveweight gain at three locations in the Queensland black speargrass zone showed that a *lo% change in rainfall was magnified to be a f 15% change in animal production (liveweight gain per ha) depending on location, temperature and CO, change. Models of 'safe' carrying capacity were developed from property data and expert opinion. Climate change impacts on 'safe' carrying capacity varied considerably across the State depending on whether moisture, temperature or nutrients were the limiting factors. Without the effect of doubling CO,, warmer temperatures and +lo% changes in rainfall resulted in -35 to +70% changes in 'safe' carrying capacity depending on location. With the effect of doubling CO, included, the changes in 'safe' carrying capacity ranged from -12 to +115% across scenarios and locations. When aggregated to a whole-of-State carrying capacity, the combined effects of warmer temperature, doubling CO, and +lo% changes in rainfall resulted in 'safe' carrying capacity changes of +3 to +45% depending on rainfall scenario and location. A major finding of the sensitivity study was the potential importance of doubling CO, in mitigating or amplifying the effects of warmer temperatures and changes in rainfall. Field studies on the impact of CO, are therefore a high research priority. Keywords: climate change, Queensland, simulation, rangelands, beef production, cattle, carrying capacity, CO,, utilisation
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Hall, Trevor J., John G. McIvor, David J. Reid, Paul Jones, Neil D. MacLeod, Cam K. McDonald, and David R. Smith. "A comparison of stocking methods for beef production in northern Australia: pasture and soil surface condition responses." Rangeland Journal 36, no. 2 (2014): 161. http://dx.doi.org/10.1071/rj13075.
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Historical stocking methods of continuous, season-long grazing of pastures with little account of growing conditions have caused some degradation within grazed landscapes in northern Australia. Alternative stocking methods have been implemented to address this degradation and raise the productivity and profitability of the principal livestock, cattle. Because information comparing stocking methods is limited, an evaluation was undertaken to quantify the effects of stocking methods on pastures, soils and grazing capacity. The approach was to monitor existing stocking methods on nine commercial beef properties in north and south Queensland. Environments included native and exotic pastures and eucalypt (lighter soil) and brigalow (heavier soil) land types. Breeding and growing cattle were grazed under each method. The owners/managers, formally trained in pasture and grazing management, made all management decisions affecting the study sites. Three stocking methods were compared: continuous (with rest), extensive rotation and intensive rotation (commonly referred to as ‘cell grazing’). There were two or three stocking methods examined on each property: in total 21 methods (seven continuous, six extensive rotations and eight intensive rotations) were monitored over 74 paddocks, between 2006 and 2009. Pasture and soil surface measurements were made in the autumns of 2006, 2007 and 2009, while the paddock grazing was analysed from property records for the period from 2006 to 2009. The first 2 years had drought conditions (rainfall average 3.4 decile) but were followed by 2 years of above-average rainfall. There were no consistent differences between stocking methods across all sites over the 4 years for herbage mass, plant species composition, total and litter cover, or landscape function analysis (LFA) indices. There were large responses to rainfall in the last 2 years with mean herbage mass in the autumn increasing from 1970 kg DM ha–1 in 2006–07 to 3830 kg DM ha–1 in 2009. Over the same period, ground and litter cover and LFA indices increased. Across all sites and 4 years, mean grazing capacity was similar for the three stocking methods. There were, however, significant differences in grazing capacity between stocking methods at four sites but these differences were not consistent between stocking methods or sites. Both the continuous and intensive rotation methods supported the highest average annual grazing capacity at different sites. The results suggest that cattle producers can obtain similar ecological responses and carry similar numbers of livestock under any of the three stocking methods.
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Pahl, Lester, Joe Scanlan, Giselle Whish, Robyn Cowley, and Neil MacLeod. "Comparing fixed and flexible stocking as adaptations to inter-annual rainfall variability in the extensive beef industry of northern Australia." Rangeland Journal 38, no. 1 (2016): 85. http://dx.doi.org/10.1071/rj15045.
Full textAbstract:
Many beef producers within the extensive cattle industry of northern Australia attempt to maintain a constant herd size from year-to-year (fixed stocking), whereas others adjust stock numbers to varying degrees annually in response to changes in forage supply. The effects of these strategies on pasture condition and cattle productivity cannot easily be assessed by grazing trials. Simulation studies, which include feedbacks of changes to pasture condition on cattle liveweight gain, can extend the results of grazing trials both spatially and temporally. They can compare a large number of strategies, over long periods of time, for a range of climate periods, at locations which differ markedly in climate. This simulation study compared the pasture condition and cattle productivity achieved by fixed stocking at the long-term carrying capacity with that of 55 flexible stocking strategies at 28 locations across Queensland and the Northern Territory. Flexible stocking strategies differed markedly in the degree they increased or decreased cattle stocking rates after good and poor pasture growing seasons, respectively. The 28 locations covered the full range in average annual rainfall and inter-annual rainfall variability experienced across northern Australia. Constrained flexibility, which limited increases in stocking rates after good growing seasons to 10% but decreased them by up to 20% after poor growing seasons, provides sustainable productivity gains for cattle producers in northern Australia. This strategy can improve pasture condition and increase cattle productivity relative to fixed stocking at the long-term carrying capacity, and its capacity to do this was greatest in the semiarid rangeland regions that contain the majority of beef cattle in northern Australia. More flexible stocking strategies, which also increased stocking rates after good growing seasons by only half as much as they decreased them after poor growing seasons, were equally sustainable and more productive than constrained flexibility, but are often impractical at property and industry scales. Strategies with the highest limits (e.g. 70%) for both annual increases and decreases in stocking rates could achieve higher cattle productivity, but this was at the expense of pasture condition and was not sustainable. Constrained flexible stocking, with a 10% limit for increases and a 20% limit for decreases in stocking rates annually, is a risk-averse adaptation to high and unpredictable rainfall variability for the extensive beef industry of northern Australia.
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McIvor, John G. "Pasture management in semi-arid tropical woodlands: dynamics of perennial grasses." Rangeland Journal 29, no. 1 (2007): 87. http://dx.doi.org/10.1071/rj06031.
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The effects of a range of pasture management options (introduced legumes and grasses, superphosphate, timber treatment, cultivation before sowing and stocking rate) on the basal cover of perennial grasses were measured from 1982 to 1991 at two sites, ‘Hillgrove’ and ‘Cardigan’, near Charters Towers, in north-east Queensland. Colonisation and survival of eight native and exotic grasses were followed in permanent quadrats in a subset of treatments. Overall, there were significant changes in total basal cover of plots between years and with tree killing, but no significant differences in sown pastures, fertiliser or stocking rate. Basal cover increased when defoliation levels were less than 40% but increases were smaller at higher levels of defoliation and basal cover often declined when defoliation was greater than 60%. Basal cover declined when growing seasons were <10 weeks, remained static with 10–15 weeks growth, and increased when growing seasons were 16 weeks or longer. There was some colonisation in all years but large differences between years. The differences in colonisation between systems were generally small but there was a general trend for higher colonisation at higher stocking rates. Bothriochloa ewartiana (Domin) C.E.Hubb. and Chrysopogon fallax S.T.Blake had low, Heteropogon contortus (L.) P.Beauv. ex Roem.&Schult., Cenchrus ciliaris L. and Aristida spp. had intermediate, and Bothriochloa pertusa (L.) A.Camus and Urochloa mosambicensis (Hack.) Dandy had high colonising ability. Survival of individual species was generally similar at both sites except for Urochloa mosambicensis. Heteropogon contortus and U. mosambicensis at ‘Hillgrove’ were short-lived (<10% survival after 4 years), B. ewartiana, Themeda triandra Forssk. and Aristida spp. had intermediate survival (10–50%), and C. ciliaris, C. fallax, B. pertusa and U. mosambicensis at ‘Cardigan’ were long-lived (>50% survival). Annual survival rates increased with plant age, were higher in good growing seasons than in poor seasons, were higher for large plants than small plants, and were lower at high defoliation levels than where defoliation was less severe. The differences between species in ability to colonise and survive, and the small influence of management compared to seasonal effects on survival, are discussed to explain species performance in pastures.
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Bastin, G., R. Denham, P. Scarth, A. Sparrow, and V. Chewings. "Remotely-sensed analysis of ground-cover change in Queensland’s rangelands, 1988–2005." Rangeland Journal 36, no. 2 (2014): 191. http://dx.doi.org/10.1071/rj13127.
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A dynamic reference-cover method and remotely-sensed ground cover were used to determine the change in the state of ~640 000 km2 of rangelands in Queensland at a sub-bioregional scale between 1988 and 2005. The method is based on persistence of ground cover in years of lower rainfall and objectively separates grazing effects on ground cover from those due to inter-annual variation in rainfall. The method is applied only to areas where trees and shrubs were not cleared. An indicator of rangeland state was derived, at Landsat-TM pixel resolution, by subtracting automatically-calculated reference ground cover from actual ground cover and then spatially averaging these deviations across the area of each sub-bioregion. Landscape heterogeneity may affect reference cover but, because it is stable over time, change in mean cover deficit between sequences of dry years reliably indicates change due to grazing. All 34 sub-regions analysed had similar or increased levels of seasonally-adjusted ground cover at the end of the analysis period, which was either 2003 or 2005. Allowing for possible landscape heterogeneity effects on assessed condition, the Einasleigh Uplands bioregion was comparatively in a better state and those analysed parts of the Mulga Lands bioregion in poorer state at the first assessment in 1988. Most sub-regions of the Cape York Peninsula, Brigalow Belt North, Desert Uplands, Gulf Plains and Mitchell Grass Downs bioregions lay between these two end-states. Simulated levels of pasture utilisation based on modelled pasture growth and statistically-based grazing pressure supported the results of this regional assessment of land condition. The dynamic reference-cover method will allow the Queensland Government to monitor future grazing effects on rangeland ground cover between sequences of drier years – quantitatively and efficiently across the entire state. The method can potentially be adapted to other rangeland jurisdictions where a suitable multi-temporal database of remotely sensed ground cover exists. The results from further analyses of remotely sensed ground cover will be reported through the Australian Collaborative Rangelands Information System.
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Lewis, Tom, David Taylor, Scott Swift, and Valerie Debuse. "Factors influencing early restoration progress of a Eucalyptus tereticornis open forest on former agricultural land." Pacific Conservation Biology 18, no. 4 (2012): 263. http://dx.doi.org/10.1071/pc120263.
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We monitored an area that was revegetated with the goal of restoring a Eucalyptus tereticornis open forest on former agricultural land in central, eastern Queensland. Revegetation involved: (1) planting 60 ha of previously cleared and heavily grazed land with eight local trees species; and (2) removing cattle grazing to encourage natural regeneration in areas where some mature trees remained. We compared the revegetation site to native pasture that had also been previously cleared, with only scattered paddock trees remaining, and continued to be managed for livestock production (an area similar to the revegetation site, prior to planting) and a remnant forest (reference area). Nine years since revegetation began there was some evidence that the revegetated site was diverging from pasture in terms of understorey plant composition, sapling density and topsoil C and N. There was little divergence in terms of plant species richness (native, introduced, grass, forb and woody plant richness), herbaceous biomass and woody plant regeneration. Some monitoring plots were subject to fire (prescribed fire and or wildfire) over the period of monitoring. With increasing time since fire, the richness of native species, introduced species and grass species (both native and introduced) declined, and forb and grass species richness declined with increasing litter biomass, suggesting that the occurrence of fire and the associated removal of litter biomass has a positive influence on herbaceous diversity in this ecosystem. Woody plant regeneration persisted through lignotubers at the revegetation site and at the pasture, but this regeneration was stunted at the pasture presumably due to livestock grazing. Hence areas of former E. tereticornis forest showed promising regenerative capacity where mature trees remained and where livestock grazing was removed.
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Letnic, Mike. "The effects of experimental patch burning and rainfall on small mammals in the Simpson Desert, Queensland." Wildlife Research 30, no. 6 (2003): 547. http://dx.doi.org/10.1071/wr02093.
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Patch-burning is frequently advocated as a management tool to enhance the biodiversity and pasture values of spinifex (Triodia) grasslands. In the northern Simpson Desert, Queensland, pastoralists use fire to reduce the likelihood of broad-scale wildfires and improve pastures for cattle. I conducted a before–after–control–impact experiment to investigate the response of small mammals to the short-term (<1 year) effects of patch-burning between August 1999 and June 2001. The experiment was replicated at three locations subject to differing rainfalls, with two 1-ha study grids remaining unburnt as controls, and two being burnt at each location. The areas burnt ranged from 1 to 3 ha. Dasycercus cristicauda and Pseudomys desertor responded negatively to the fire treatment. Notomys alexis responded positively to the fire treatment in the final trapping session but only at one location. Factors indicative of temporal and spatial variation in rainfall, time and site had a greater effect on the abundance of small mammals than the fire treatment. Heavy rainfalls in 2000 increased seed production and prompted increases in the populations of rodent species and Dasycercus cristicauda. The greatest numbers of captures were made at the sites that received the highest rainfalls. Patch-burning regimes are likely to increase the resilience of 'fire-sensitive' species dependent on dense spinifex by reducing the extent of wildfires.
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HOLT, J. A., and R. J. COVENTRY. "The effects of tree clearing and pasture establishment on a population of mound-building termites (Isoptera) in North Queensland." Austral Ecology 13, no. 3 (September 1988): 321–25. http://dx.doi.org/10.1111/j.1442-9993.1988.tb00980.x.
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