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1
Miller, S. M., D. A. Pritchard, S. J. Eady, and P. R. Martin. "Polyethylene glycol is more effective than surfactants to enhance digestion and production in sheep fed mulga (Acacia aneura) under pen and paddock conditions." Australian Journal of Agricultural Research 48, no. 8 (1997): 1121. http://dx.doi.org/10.1071/a96127.
Повний текст джерелаАнотація:
Chemicals that interfere with the formation of tannin-protein complexes were evaluated as dietary additives for mulga-fed sheep in pens and under paddock conditions. Condensed tannins (CT) in mulga inhibit protein digestion, and the use of chemicals to precipitate CT or dissociate CT-protein complexes may improve production from sheep consuming a mulga diet. In a digestion study with mulga-fed sheep in pens, provision of polyethylene glycol (PEG) at a rate of 6 g/day significantly (P < 0·05) improved nitrogen (N), phosphorus (P), and sulfur (S) balance, and apparent N, P, dry matter (DM), and organic matter digestibility, and the rate of liveweight gain. Addition of the surfactants SDS or alkanate 3SL3 to the diet of mulga-fed sheep did not improve N balance or digestion; however, apparent digestibility of P, and P and S balance, were significantly improved by SDS. Teric PE64, a compound structurally similar to PEG, significantly improved S balance, but not DM intake or N balance. For sheep consuming a predominantly mulga diet under paddock conditions, provision of PEG at a rate of 12 g/day significantly improved clean wool growth and liveweight gain compared with unsupplemented sheep, by 9% and 100%, respectively (0·809 v. 0·745 mg/cm2.day, and 44 v. 22 g/day). The studies demonstrated that although surfactants can affect mulga digestion, using PEG to precipitate CT is more effective to improve mulga digestion and animal production than the use of surfactants. However, the wool and liveweight production responses achieved with PEG were not sufficient to justify its wide-scale use for mulga-fed sheep. Consequently, alternative methods should be sought to reduce the negative effects of mulga CT on sheep production.
2
Silcock, J. L., J. Drimer, J. Fraser, and R. J. Fensham. "Inability of fire to control vegetation dynamics in low-productivity mulga (Acacia aneura)-dominated communities of eastern Australia." International Journal of Wildland Fire 26, no. 10 (2017): 896. http://dx.doi.org/10.1071/wf17011.
Повний текст джерелаАнотація:
Reduced fire frequency and severity associated with livestock grazing are cited as a cause of woody plant encroachment and thickening in rangelands, but such paradigms are difficult to test experimentally owing to limited opportunities to burn. Mulga (Acacia aneura) dominates 25% of the Australian continent and epitomises this quandary. We measured the effect of rare wildfires on tree and shrub mortality and subsequent regeneration in mulga-dominated communities to critically examine prevailing but unsubstantiated paradigms of vegetation structural change. Mortality of mature mulga trees was positively correlated with fire severity, which was negatively correlated with tree basal area per hectare. High-severity fires killed the majority of mulga, but only occurred in more open areas, whereas low-severity fires typical of many mulga communities did not kill substantial proportions of mature mulga. The majority of mulga saplings were killed across all sites regardless of fire severity. Seedling germination was stimulated by fire, but not dependent on it. Green turkey bush (Eremophila gilesii) was the only shrub species with >50% mortality across all sites. Combined with the rarity of fire events in the historical record, our results, particularly limited fire mortality and enhanced post-fire seedling recruitment, suggest that the role of fire in shaping vegetation structure in mulga-dominated communities has been overstated. The decoupling of fire and vegetation structure is consistent with emerging regional studies in low-productivity semiarid environments.
3
Greene, RSB. "Soil physical properties of three geomorphic zones in a semiarid mulga woodland." Soil Research 30, no. 1 (1992): 55. http://dx.doi.org/10.1071/sr9920055.
Повний текст джерелаАнотація:
Soil physical properties were measured in three contiguous geomorphic zones of a patterned sequence of alternating groves and intergroves in a semi-arid mulga (Acacia aneura) woodland : (1) a runoff zone of stony, severely sealed, surface soil, (2) an interception zone at the bottom of the runoff zone, and adjoining (3) a runon zone of mulga groves. Infiltration was measured in the field under unsaturated and saturated conditions using a disc permeameter at water supply potentials of -40 and +10 mm respectively. Under unsaturated flow conditions, there were no significant differences in the sorptivity, three-dimensional infiltration rate and hydraulic conductivity between the three zones. However, under saturated flow conditions, the soils in the mulga groves had infiltration rates 5-10 times higher than the soils in the runoff and interception zones. This difference was explained by the presence of stable macropores >0.75 mm diameter in the mulga grove soils. Surface soil (0-10 mm) aggregates from mulga groves were also particularly stable to rapid wetting, measured by wet-sieving. Volumetric water contents (measured over a range of matric potentials from 0 to -5.0 kPa) of the 0-50 mm layer of soil from the mulga grove and interception zone were significantly (P = 0.05) higher than the 0-50 mm layer from the runoff zone. Micromorphological and scanning electron microscope (SEM) examination indicated that the total porosity of the soil surface from the mulga groves and interception zones was greater than that of the runoff zones. Measurement of soil-water content following a major rainfall event indicated that water had flowed off the runoff zones and accumulated in the mulga groves. These findings are consistent with the higher herbage production and biotic activity that is found to occur in the mulga grove and interception zone compared with the runoff zone following adequate rainfall. They also reveal part of the delicate balance of runoff redistribution in grove/intergrove areas and the potential for management to alter this balance.
4
Brown, RF. "The growth and survival of young Mulga (Acacia aneura F. Muell) trees under different levels of grazing." Rangeland Journal 7, no. 2 (1985): 143. http://dx.doi.org/10.1071/rj9850143.
Повний текст джерелаАнотація:
The effects on the survival and growth of young mulga trees exposed to five levels of sheep graztng were monitored over bur years. The levels ranged from complete exclusion of domest~c stock to continuous grazing at a projected annual consumption rate of 20%, 35%, 50%, or 80% of the total available forage (grass, herbage, and accessible mulga leaf). Innially, all trees were less than 90 cm tall. Four years later, the ungrazed trees had more than doubled in he~ght whereas thegrazed trees were not significantly taller, irrespective of grazing intensity. Over 90% of the ungrazed trees had grown above the upper limit of sheep browsing (I20 cm) and their growth was considered unlikely to be prejudiced by subsequent grazing. Stem diameters nearly trebled in ungrazed mulga but much smaller Increases (averagmg25%) occurred in grazed plants. Overall, 36% of the young trees died. Most deaths occurred during the winter of 1980 and summer of 1982183 after protracted periods of dry weather. Grazing had little or no e,ffect on death rates. Even the lightest grazing arrested mulga growth and prevented the transition from low mulga to the tailer forms used for drought feeding. This is discussed as a possible cause of reported declines in drought reserves of mulga. The results of this study illustrate the need to ensure that grazing strategy is compatible with uninterrupted replacement of umbrella mulga (5-8 m high) cut for drought fodder.
5
Recher, Harry F., and William E. Davis Jr. "Foraging Ecology of a Mulga Bird Community." Wildlife Research 24, no. 1 (1997): 27. http://dx.doi.org/10.1071/wr96052.
Повний текст джерелаАнотація:
Mulga is a distinctive woodland or shrub community with a wide distribution across the semi-arid zone of southern and central Australia. Mulga (Acacia aneura) is the dominant shrub and small tree, but other species of Acacia are common. Typical of Australian habitats in the arid zone, mulga has a core of resident bird species that is augmented by nomadic (opportunistic) species when conditions are favourable. This paper describes the foraging behaviour and habitat use of a mulga avifauna in the vicinity of Alice Springs during late winter, when many opportunistic species were present. Data were obtained for 24 species, of which 16 were confirmed as nesting. Many birds, regardless of their normal foraging habits, converged on a common food resource: a geometrid moth (Geometridae) that was abundant on mulga plants. Despite their use of a common food resource, species differed in their foraging behaviour, proportions of different substrates used, and foraging heights. Ground-foraging species dominated the avifauna, but in most respects the guild structure of the community was a scaled-down version of Eucalyptus forest avifaunas. Differences in guild structure between mulga and eucalypt forest are best explained by differences between the two habitats in the kinds of resources (e.g. foraging substrates, types of food) that are available.
6
Dalal, R. C., B. P. Harms, E. Krull, W. J. Wang, and N. J. Mathers. "Total soil organic matter and its labile pools following mulga (Acacia aneura) clearing for pasture development and cropping. 2. Total and labile nitrogen." Soil Research 43, no. 2 (2005): 179. http://dx.doi.org/10.1071/sr04076.
Повний текст джерелаАнотація:
Mulga (Acacia aneura) woodlands and open forests occupy about 150 Mha in Australia, and originally occupied 11.2 Mha in Queensland. Substantial areas (1.3 Mha) of the mulga vegetation have been cleared in Queensland, mostly for pasture production, but some areas are also used for cereal cropping. Twenty years after mulga clearing we found a significant loss of total soil organic C (28–35% from the 0–0.05 m depth) and light fraction C (>50% from the 0–1 m depth) from soil under pasture and cropping at a site in southern Queensland. We report here the changes in soil N and labile N pools in a paired-site study following conversion of mulga to buffel pasture (Cenchrus ciliaris) and cereal (mostly wheat) cropping for more than 20 years. Conversion from mulga forest to pasture and cultivation resulted in greater losses of soil N than organic C in the top 0.1 m depths. As a result, C/N ratios in soil under both pasture and cropping were higher than soil under mulga, indicating a decline in soil organic matter quality after mulga clearing. Although land-use change had no significant effect on 15N natural abundance (δ15N) values of total soil N down to a depth of 1 m, δ15N values of wheat tops and roots indicated that the primary source of N under cropping was soil organic N, while that of buffel pasture was a mixed source of soil N and decomposed litter and root N. Light fraction N (<1.6 Mg/m3) declined by 60–70% throughout the 1 m soil profile under pasture and cropping, but it was 15N-enriched in these 2 land-use systems. The δ15N values of mulga phyllodes, twigs, and fine roots, indicated an input of atmospheric fixed N2 that was estimated to be about 25 kg N/ha.year. However, the source and magnitude of this N resource needs to be confirmed. Soil N losses were estimated to be 12 kg N/ha.year under pasture and 17 kg N/ha.year under cropping over a 20-year period. These findings raise the issue of the long-term sustainable use of cleared mulga areas for pasture and/or cropping. The labile C and N pools and N mineralised also declined, which would have an immediate adverse effect on soil fertility and plant productivity of cleared Mulga Lands, as well as reducing their potential as a soil sink for greenhouse gases.
7
Lauerer, Marianne, Dean Nicolle, Malcolm French, Annett Börner, Gregor Aas, and Ernst-Detlef Schulze. "Marri, Mallee, Mulga: Pflanzenvielfalt Westaustraliens." Der Palmengarten 75, no. 1 (June 30, 2011): 31–42. http://dx.doi.org/10.21248/palmengarten.110.
Повний текст джерелаАнотація:
Westaustralien ist einer der „Hot Spots“ der Biodiversität der Erde. Es beherbergt über 10 000 Pflanzenarten, darunter viele endemische. Von besonderer Bedeutung für diese Region sind Eukalypten, zu denen neben der bekannten Gattung Eucalyptus auch Corymbia gehört, die erst in jüngerer Zeit als eigene Gattung von Eucalyptus abgetrennt wurde. Dargestellt werden verschiedene von Eukalypten dominierte Vegetationstypen Westaustraliens, ferner die küstennahen Banksia-Heidegebüsche im Südwesten, Acacia-Buschländer und die halbimmergrünen Trockenwälder und Savannen der Kimberleys.
8
Nicholas, Anstee M. M., Donald C. Franklin, and David M. J. S. Bowman. "Coexistence of shrubs and grass in a semi-arid landscape: a case study of mulga (Acacia aneura, Mimosaceae) shrublands embedded in fire-prone spinifex (Triodia pungens, Poaceae) hummock grasslands." Australian Journal of Botany 57, no. 5 (2009): 396. http://dx.doi.org/10.1071/bt07157.
Повний текст джерелаАнотація:
The persistence of relatively fire-sensitive mulga (Acacia aneura F.Muell. ex Benth., Mimosaceae) shrublands within a landscape matrix of highly flammable spinifex (Triodia spp. R.Br., Poaceae) hummock grassland is a central question in the ecology of semiarid Australia. It is also a special case of questions about the coexistence of grasses and woody plants that have general application in semiarid rangelands and tropical savannas. With the use of field surveys and a 24-year fire history, we examined their coexistence on a sandplain in the Tanami Desert, Northern Territory, Australia. Mulga and spinifex each formed discrete monodominant stands with generally abrupt boundaries that did not correspond to obvious edaphic or topographic discontinuities. Spinifex hummock grasslands burnt almost three times as often as mulga shrublands and tended to occur on lighter soils with less biological crusting and more physical soil crusting. A combination of fire and soil variables described the environmental partitioning better than did either alone. Biological crusting increased with time since fire in both vegetation types. The demographic structure of mulga stands reflected their fire history, the more frequently burnt stands comprising almost entirely small plants. One fifth of mulga plants <0.5 m tall were resprouts. Our data provide support for the hypothesis that abrupt boundaries between mulga shrublands and spinifex hummock grasslands can be generated across diffuse environmental gradients by fire–soil–vegetation feedback loops. The oft-severe demographic impact of fire on mulga that is burnt raises questions about the appropriateness of frequent intense fires in this landscape.
9
Dalal, R. C., B. P. Harms, E. Krull, and W. J. Wang. "Total soil organic matter and its labile pools following mulga (Acacia aneura) clearing for pasture development and cropping 1. Total and labile carbon." Soil Research 43, no. 1 (2005): 13. http://dx.doi.org/10.1071/sr04044.
Повний текст джерелаАнотація:
Mulga (Acacia aneura) dominated vegetation originally occupied 11.2 Mha in Queensland, of which 12% has been cleared, mostly for pasture production, but some areas are also used for cereal cropping. Since mulga communities generally occupy fragile soils, mostly Kandosols and Tenosols, in semi-arid environments, clearing of mulga, which continues at a rate of at least 35 000 ha/year in Queensland, has considerable impact on soil organic carbon (C), and may also have implications for the greenhouse gas emissions associated with land use change in Australia. We report here the changes in soil C and labile C pools following mulga clearing to buffel pasture (Cenchrus ciliaris) and cereal (mostly wheat) cropping for 20 years in a study using paired sites. Soil organic C in the top 0.05 m of soil declined by 31% and 35% under buffel pasture and cropping, respectively. Land use change from mulga to buffel and cropping led to declines in soil organic C of 2.4 and 4.7 t/ha, respectively, from the top 0.3 m of soil. Using changes in the δ13C values of soil organic C as an approximate representation of C derived from C3 and C4 vegetation from mulga and buffel, respectively, up to 31% of soil C was C4-derived after 20 years of buffel pasture. The turnover rates of mulga-derived soil C ranged from 0.035/year in the 0–0.05 m depth to 0.008/year in the 0.6–1 m depths, with respective turnover times of 29 and 133 years. Soil organic matter quality, as measured by the proportion/amount of labile fraction C (light fraction, < 1.6 t/m3) declined by 55% throughout the soil profile (0–1 m depth) under both pasture and cropping. There is immediate concern for the long-term sustainable use of land where mulga has been cleared for pasture and/or cropping with a continuing decline in soil organic matter quality and, hence, soil fertility and biomass productivity. In addition, the removal of mulga forest over a 20-year period in Queensland for pasture and cropping may have contributed to the atmosphere at least 12 Mt CO2-equivalents.
10
McMeniman, NP, IF Beale, and GM Murphy. "Nutritional evaluation of south-west Queensland pastures. 1. The botanical and nutrient content of diets selected by sheep grazing on Mitchell grass and mulga/grassland associations." Australian Journal of Agricultural Research 37, no. 3 (1986): 289. http://dx.doi.org/10.1071/ar9860289.
Повний текст джерелаАнотація:
The botanical composition and nutrient content of diets selected by sheep grazing Mitchell grass (Astrebla spp.) and mulga (Acacia aneura)/grassland pastures in south-west Queensland were studied during a four-year period. Forbs, when present in the sward, contributed significantly to the diets on both grassland types. Under drought conditions grasses were the major components of the diets of sheep grazing Mitchell grassland pastures, while under similar conditions on the mulga/grassland pastures at least 35% of the diet was mulga (Acacia aneura); some mulga was present in the diet at all times. In general, the nutrient content of the green leaves of grasses and forbs growing on the mulga/ grassland association was similar, whereas on the Mitchell grass association green forbs had a higher nutrient concentration than did the leaves of green grasses. Both the grasses and forbs on the mulga/ grassland site had lower P and sodium concentrations than those on the Mitchell grassland site. When seasonal conditions were average to good the concentrations of all nutrients in the diets of sheep grazing the Mitchell grass association were judged to be adequate. However, when the pastures dried out the diets contained low concentrations of N (7.0 g/kg DM), P (0.9 g/kg DM), sodium (O.lg/kg DM) and copper (3.8 mg/kg DM). On the mulga/grassland site dietary concentrations of P and sodium were low at all times and under drought conditions the N:S ratio fell to 16.8:1. The concentrations of other nutrients in the diets were high enough to provide the sheep's theoretical requirements at all times.
11
Page, M., RJS Beeton, and JJ Mott. "Grass response to shrub removal in two semi-arid vegetation communities." Rangeland Journal 22, no. 2 (2000): 220. http://dx.doi.org/10.1071/rj0000220.
Повний текст джерелаАнотація:
The control of woody weeds in the mulga lands of south-west Queensland is commonly regarded as essential for restoration of degraded systems. However, these shrubs have become a dominant and stable component of many mulga land ecosystems, and their removal may have unknown ecosystem impacts. This paper reports an experiment to determine the effect of woody weeds and grazing pressure on grass recruitment, cover and diversity in two vegetation communities in Queensland's mulga lands. Both factors influence grass recruitment, cover and diversity, but the response differs between the two vegetation communities investigated. The overall grass cover is consistently greater in sites where woody weeds were removed, and where grazing pressure was lowest. However, in the Dunefields community the cover and frequency of grass plants responded more to the removal of woody weeds than in the Mulga Sandplain community. In contrast, in the Mulga Sandplain community the grasses responded more to reducing or removing grazing pressure. Results suggest that subtle differences between systems influence grass dynamics, highlighting the need for community-specific research and management. Key words: shrub removal, semi-arid vegetation, vegetation communities, woody weeds
12
Miller, S. M., A. V. Klieve, J. J. Plumb, R. Aisthorpe, and L. L. Blackall. "An in vitro cultured rumen inoculum improves nitrogen digestion in mulga-fed sheep." Australian Journal of Agricultural Research 48, no. 4 (1997): 403. http://dx.doi.org/10.1071/a96100.
Повний текст джерелаАнотація:
Mixed cultures of anaerobic micro-organisms were derived from feral goat rumen fluid (FGRF) using a laboratory fermentor to selectively culture microbes actively degrading mulga, and were evaluated as rumen inocula in digestion and liveweight studies with mulga-fed sheep. When placed in the rumen of sheep, FGRF enhances mulga digestion; however, limited supplies of feral goats, the labour involved in locating and mustering goats, and likely variations in the microbial composition of FGRF between animals and localities make the production of an in vitro cultured inoculum a desirable alternative to enable widespread adoption. The cultured inoculum significantly (P < 0·05) improved nitrogen digestion and retention in mulga-fed sheep by 16 and 76%, respectively. Inocula consisting of simplified mixtures of bacteria isolated from sheep, feral goats, and native marsupials did not affect mulga digestion. In the first of 2 liveweight studies, sheep inoculated with the fermentor inoculum lost significantly less weight than uninoculated sheep for the first 57 days (0·3 v. 4·6 kg); however, after 83 days the difference in the rate of liveweight loss between the fermentor inoculum group and the uninoculated sheep was not significant (53 v. 95 g/day). In the second study, liveweight loss was not significantly reduced by the fermentor inoculum. An inoculum based on FGRF, and produced in vitro using a fermentor, is potentially valuable to grazing enterprises reliant on mulga-fed sheep. However, problems in generating a consistent inoculum need to be addressed before such an inoculum can be generally considered.
13
Miller, SM, JD Brooker, and LL Blackall. "A feral goat rumen fluid inoculum improves nitrogen retention in sheep consuming a mulga (Acacia aneura) diet." Australian Journal of Agricultural Research 46, no. 8 (1995): 1545. http://dx.doi.org/10.1071/ar9951545.
Повний текст джерелаАнотація:
Rumen micro-organisms which are resistant to high levels of condensed tannins (CT) may constitute a unique response by feral goats to the nutritive depressing effects of mulga (Acacia aneura) CT. Transferring these micro-organisms to domestic livestock lacking this response may be beneficial when CT-rich mulga diets are consumed. Three experiments were conducted in which sheep consuming a mulga diet were given a ruminal inoculation of feral goat rumen fluid (FGRF). Feed intake and nitrogen (N) retention were significantly greater (P < 0.05) in both sheep and domestic goats following inoculation and in inoculated compared with uninoculated sheep. Inoculation also improved N digestibility and reduced the rate of liveweight loss in sheep and domestic goats. These improvements were of similar magnitude to those attributable to the traditional N, phosphorus and sulfur mineral supplement for mulga fed sheep. FGRF inoculated sheep also grew as much wool as uninoculated sheep receiving a production enhancing mineral supplement. The results from these experiments suggest that FGRF is readily transferable to sheep and improves N metabolism in these animals. Using micro-organisms from FGRF as an inoculum for sheep consuming a mulga diet has the potential to be an alternative to mineral supplements.
14
Baker, DE, RL Miles, and VJ Eldershaw. "Vegetation Cover Classes and Soil Nutrient Status of the Mulga Lands of South-West Queensland." Rangeland Journal 14, no. 1 (1992): 40. http://dx.doi.org/10.1071/rj9920040.
Повний текст джерелаАнотація:
The soils of the semi-arid mulga lands of south-west Queensland are subject to degradation from both erosion and woody weeds. Limited quantification of the nutrient changes in the red earths under these forms of degradation indicates that eroded land has a lower phosphorus level in the surface soil, a lower pH at depth and an inverse electrical conductivity profile, compared with land vegetated by mulga or grassland. Land invaded by turkey bush did not differ in nutrient characteristics from mulga or grassland. It is concluded that phosphorus will play a critical role in any regeneration programme for eroded land.
15
Turner, J. C., M. H. Friedel, and M. Neumann. "Phyllode fall and nutrient content in a mulga (Acacia aneura F.Muell. ex Benth.) community in central Australia in response to rainfall." Rangeland Journal 43, no. 1 (2021): 1. http://dx.doi.org/10.1071/rj21007.
Повний текст джерелаАнотація:
The fall of phyllodes from Acacia aneura F.Muell. ex Benth. (mulga) in central Australia was studied over 22 months from mid-1958 at four locations within a livestock reserve north of Alice Springs in the Northern Territory, in order to identify rainfall or seasonal triggers. Phyllode fall increased by at least an order of magnitude for short periods following rain of 15–20mm or more on a ‘mature’ mulga site and similar trends were apparent for ‘young’ and ‘desert form’ mulga on the same site, and on a second, independent, ‘mature’ site. When rates of phyllode fall were high after substantial rain, at both ‘mature’ locations, ~30% of nitrogen and ~50% of phosphorus were withdrawn before abscission, suggesting that mulga was markedly conservative of these nutrients. Conversely, under dry conditions, when phyllode fall was relatively low (<200mgm−2day−1), concentrations of nitrogen and phosphorus in fallen phyllodes were higher. Concentrations of potassium, calcium, magnesium and sodium did not vary consistently with increasing rate of phyllode fall, although overall levels of calcium and potassium were considerably higher in the second ‘mature’ location. This legacy study is of renewed interest given the potential of mulga communities to contribute to national carbon stocks, and the consequent need for robust field-based data on growth dynamics and carbon fluxes.
16
Ward, Bruce G., Thomas B. Bragg, and Barbara A. Hayes. "Relationship between fire-return interval and mulga (Acacia aneura) regeneration in the Gibson Desert and Gascoyne–Murchison regions of Western Australia." International Journal of Wildland Fire 23, no. 3 (2014): 394. http://dx.doi.org/10.1071/wf13007.
Повний текст джерелаАнотація:
A study of 26 burnt mulga (Acacia aneura) stands was conducted from 2003 to 2012 in the Gibson Desert and eastern Gascoyne–Murchison region of Western Australia to assess the effect of fire interval on seedling regeneration. Tree-ring analysis and Landsat satellite imagery identified mulga stands with fire intervals ranging from 3 to 52 years. Results show fire-return intervals less than 20 years produce 2–3-year-old seedling regeneration lower than 50% of the original adult stand population (average juvenile-to-adult ratio=0.49). In total, 6 of the 26 stands sampled had reburnt within 3 to 10 years of the previous burn, a consequence of increased plant growth associated with higher rainfall. For all fires, summer fires were larger and more frequent (24 of 35 fires recorded, median fire size=150km2) than spring fires (median fire size=91km2). This study emphasises the important role of fire in maintaining the diversity and vigour of the mulga–Triodia ecosystem but indicates a minimum fire-return interval of 26 years to maintain mulga populations.
17
Friedel, MH. "The population structure and density of central Australian trees and shrubs, and relationships to range condition, rabbit abundance and soil." Rangeland Journal 7, no. 2 (1985): 130. http://dx.doi.org/10.1071/rj9850130.
Повний текст джерелаАнотація:
The regional variation in population structure and density of trees and shrubs was investigated in four central Australian pasture types: open woodland, mulga annual, calcareous shrubby grassland and bluebush nse. The possible influences of range condition, rabbit abundance, soil erosion and so11 characteristics were examined, and the likelihood of long-term change was cons~dered. Density at some woodland and mulga sites was potentially high enough to depress pasture yield. The most common "increaser"species were Casszaspp. in open woodland and mulga (Acaciaaneura) in mulga annual. None of the measured influences related closely to population structure and density, and it is argued that changed fire regimes are most likely to have led to increasing densities of trees and shrubs. Density in calcareous shrubby grasslands was related to rabbit abundance, and smaller size classes of trees and shrubs were severely depleted whererab- bits were plentiful. Continuing loss of the woody plant resource is forecast, if rabbits are not controlled. Other measured influences were not related to woody plant population characteristics. Bluebush (Maireana miroiricha) populations were considered to be relatively stable under current management of bluebush rises.
18
McMeniman, NP, IF Beale, and GM Murphy. "Nutritional evaluation of south-west Queensland pastures. 2. The intake and digestion of organic matter and nitrogen by sheep grazing on Mitchell grass and mulga grassland associations." Australian Journal of Agricultural Research 37, no. 3 (1986): 303. http://dx.doi.org/10.1071/ar9860303.
Повний текст джерелаАнотація:
The intake and digestion of organic matter and nitrogen by sheep grazing two Mitchell and one mulga/ grassland association was studied under a variety of seasonal conditions. The in vitro digestibility of the diets selected by sheep grazing both pasture types was in the range 60-70% when seasonal conditions were good, but fell to 52.3% and 48.2% for the Mitchell and mulga/ grasslands respectively when the pasture were dry. Digestible organic matter intakes of intact sheep grazing the Mitchell grass pastures were 14.0-16.3 g (kg W)-1 day-1 when seasonal conditions were average to good and 13.5 g (kg W)-1 day-1 after the pastures had dried out. Comparable figures on the mulga/grassland pastures were 17.8-18- 1 g (kg W)- day- with good seasonal conditions and 11.8 g (kg W)-1 day-1 with dry pasture. The nitrogen concentrations in the diets varied from 7 to 26 g/kg OM on the Mitchell grass associations and from 17 to 34 g/kg OM on the mulga/grassland. Apparent digestion of dietary N within the rumen ranged from 70% to 90% on both sites when there was green forage in the diets, but fell to 58.5% and 37.6% on the Mitchell and mulga/grassland respectively when the pastures were drought affected. Under the latter conditions the quantity of amino acid N absorbed from the small intestines was depressed at both sites, as was the efficiency of microbial N production in sheep grazing the Mitchell grass pastures. These findings are discussed in relation to the protein and energy requirements of sheep grazing the two pasture associations.
19
Recher, Harry F., and William E. Davis Jr. "Foraging behaviour of mulga birds in Western Australia. I. Use of resources and temporal effects." Pacific Conservation Biology 24, no. 1 (2018): 74. http://dx.doi.org/10.1071/pc17031.
Повний текст джерелаАнотація:
The foraging behaviour of mulga birds in the Murchison and Gascoyne Bioregions was studied in 1999 following a period of heavy rain and again in 2002 when it was dry. Mulga birds allocated foraging resources in a similar fashion to other bird communities, with species differing in the way that prey were taken, the substrates and plant species on which prey were found, and the heights at which prey were sought. The numbers of birds and bird species in the study areas declined with drier conditions and there was less breeding activity. Nomadic species, including honeyeaters, seed-eaters, and insect-eaters, largely left the area as it became drier and food resources changed. The birds that remained foraged differently when it was drier than when conditions were wetter and food more abundant. These observations illustrate the fragility of the mulga avifauna and its likely sensitivity to long-term climate change with predicted increasing temperatures, more extreme heat events, and reduced winter rainfall. Conservation of mulga birds and associated flora and fauna requires a whole-of-landscape approach and the adoption of land management practices by Australian governments and land managers that will allow species to adapt to climate change and guarantee their right to evolve.
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Recher, Harry F. "Foraging behaviour of mulga birds in Western Australia. II. Community structure and conservation." Pacific Conservation Biology 24, no. 1 (2018): 87. http://dx.doi.org/10.1071/pc17032.
Повний текст джерелаАнотація:
Mulga (Acacia aneura) woodlands dominate much of arid and semiarid Australia. Although mulga woodlands are floristically and structurally diverse, the composition of the mulga avifauna is consistent across the continent, with 50–70% of bird species shared between sites and a high proportion of migratory and nomadic species. A comparison of avian foraging guilds in mulga woodlands in the Murchison and Gascoyne Bioregions of Western Australia with those in the Northern Territory identified nine guilds. All guilds occurred at the three locations studied during wet years. The number of bird species, species’ abundances, and the number of guilds declined on the Western Australian sites when there was less rain. Despite the commonality of guilds and species between sites, there were differences between sites and years in the grouping of species, with many species best associated with two or more guilds. These differences reflected differences between locations and wet and dry years in the food resources available to birds, which affected how species foraged. Particularly noticeable were the differences between sites and years in migratory and nomadic birds, which in Western Australia and the Northern Territory were the most abundant birds during wet conditions, but largely absent when conditions were drier.
21
Fensham, Roderick J., Owen Powell, and James Horne. "Rail survey plans to remote sensing: vegetation change in the Mulga Lands of eastern Australia and its implications for land use." Rangeland Journal 33, no. 3 (2011): 229. http://dx.doi.org/10.1071/rj11007.
Повний текст джерелаАнотація:
There is a prevailing paradigm that woody vegetation is expanding at the expense of grassland with reduced burning under pastoralism in the Mulga Lands biogeographic region in eastern Australia. This raises the possibility that the region is acting as a carbon sink. Vegetation boundaries were precisely positioned from rail survey plans dating from 1895 to 1900. This baseline was compared with the position of boundaries on 1952 aerial photography and 2010 Google Earth imagery. The conversion of forest to non-forest by mechanical clearing was also mapped from satellite imagery. There was no consistent trend in the direction of boundary movement for mulga (Acacia aneura F.Muell. ex Benth.), gidgee (Acacia cambagei R.T. Baker) forest or miscellaneous other forest types. The stability of the boundaries, despite the transition from aboriginal management to rangeland pastoralism, contrasts with dramatic declines in tree cover resulting from mechanical clearing. Mapping of forest cover from satellite imagery reveals that conversion of forest to non-forest has reduced mulga forest to 74%, gidgee forest to 30% and miscellaneous forest types to 82% of their original area. Annual clearing rates for the period between 1997 and 2005 were 0.83, 0.95 and 0.43% for those forest types, respectively. Clearing has declined substantially in the period 2005–09 since the advent of recent regulations in Queensland. The area remains a source of carbon emissions but this situation may reverse if restoration of mulga dry forest becomes an attractive land use with an emerging carbon market.
22
Silcock, J. L., G. B. Witt, and R. J. Fensham. "A 150-year fire history of mulga (Acacia aneura F. Muell. ex Benth.) dominated vegetation in semiarid Queensland, Australia." Rangeland Journal 38, no. 4 (2016): 391. http://dx.doi.org/10.1071/rj15109.
Повний текст джерелаАнотація:
Changes to fire regimes associated with European colonisation are implicated in declines in biodiversity and productivity in rangelands globally. However, for many areas there is incomplete knowledge of historical fire regimes and purported changes can become accepted wisdom with little empirical evidence. In the Mulga Lands of south-western Queensland, the dominant narrative implicates reduced fire frequency as a cause of woody vegetation thickening. We present a fire history of the Mulga Lands since pastoral exploration in the 1840s based on a review of explorer and early pastoralist journals, newspaper articles, interviews with long-term landholders and collation of satellite imagery. Fires in mulga communities are infrequent and only occur after at least two years of above-average summer rainfall. The assumption of regular pre-pastoral fires is not supported by available evidence. Since pastoral settlement in the 1860s, fire events affecting >1000 km2 have occurred seven times (1891–1892, 1904, 1918, 1950–1951, 1956–1957, 1976–1979 and 2011–2013), with only the 1950s fires affecting a >10% of the total area of mulga-dominated vegetation. We argue that fire is limited by fuel loads, which are in turn limited by rainfall events occurring only a few times a century. Even in the absence of grazing and active fire suppression fire intervals would be extremely long, perhaps 30–50 years in relatively fire-prone communities and much longer throughout most of the region. Combined with quantitative studies of fire and tree and shrub population dynamics, detailed fire histories will allow for more informed and nuanced debates about the role of fire in rangelands subject to abrupt management upheavals.
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Bennison, Kerrie, Christopher R. Dickman, and Robert Godfree. "Habitat use and ecological observations of the Ooldea dunnart (Sminthopsis ooldea) at Uluru–Kata Tjuta National Park, Northern Territory." Australian Mammalogy 35, no. 2 (2013): 175. http://dx.doi.org/10.1071/am12048.
Повний текст джерелаАнотація:
The Ooldea dunnart (Sminthopsis ooldea) is a small (10–11 g) and poorly known dasyurid marsupial that is endemic to the central and western arid regions of Australia. Surveys carried out at Uluru–Kata Tjuta National Park, Northern Territory, from 1994 to 2010 yielded 37 captures of this elusive species, providing novel insights into its biology. Most captures were made in pitfall traps, with spring breeding confirmed by the presence of pregnant or lactating females during October and November. Animals were captured in mallee and mulga woodland and spinifex (Triodia spp.) dominated dune fields and sand plains. Capture rates were variable in most habitat types, but were relatively consistent in one site dominated by mulga (Acacia aneura). Although we found no consistent association between captures of S. ooldea and prior rainfall, fewest animals were captured in the two wettest years of the study. Ooldea dunnarts showed no clear response to fire. We suggest that mulga is a key habitat for S. ooldea, but also that the demography of this species may be shaped by biotic and/or abiotic factors that remain to be fully elucidated.
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Read, J. L., G. R. Johnston, and T. P. Morley. "Predation by snakes thwarts trial reintroduction of the Endangered woma pythonAspidites ramsayi." Oryx 45, no. 4 (August 31, 2011): 505–12. http://dx.doi.org/10.1017/s0030605310001110.
Повний текст джерелаАнотація:
AbstractCase studies of well-documented snake reintroductions are limited, despite their potential value for conservation and ecosystem recovery. The Endangered womaAspidites ramsayiis a large boid snake that has declined considerably and is now threatened throughout much of central Australia. We describe a trial release of captive-bred womas into the feral predator-free Arid Recovery Reserve in northern South Australia. All of the reintroduced womas were killed within 4 months, with predation by the mulga snakePseudechis australisconfirmed or implied in all cases. Lessons learned for the conditioning of captive-bred snakes for wild release and the role of the mulga snake in structuring Australian arid-zone snake assemblages are discussed.
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Silcock, RG, LM Williams, KJ Lehane, and FT Smith. "Seasonal distribution of herbage growth from sandplain Mulga country, Charleville." Rangeland Journal 7, no. 2 (1985): 99. http://dx.doi.org/10.1071/rj9850099.
Повний текст джерелаАнотація:
Sod moisture may be adequate for rapid plant growth for prolonged periods at any time of year In the Charleville district. However, in pastures growing on mulga soils (acid, red earths), the majority of herbage is produced during the warm summer season (October 1 - March 31). Winter rams have to be well above average for herbage grown during these months to exceed 50% of annual production. The predominance of summer-growing (C4) grasses and absence of cool season grasses in the regional flora is the main reason for this pattern. The density of mulga scrub has no effect on seasonal distribution of herbage production despite major differences in botanical composition. Increased tree density reduced herbage yields but increased the protein and mineral content of this fodder
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Andrew, Rose L., Joseph T. Miller, Rod Peakall, Michael D. Crisp, and Randall J. Bayer. "Genetic, cytogenetic and morphological patterns in a mixed mulga population: evidence for apomixis." Australian Systematic Botany 16, no. 1 (2003): 69. http://dx.doi.org/10.1071/sb01043.
Повний текст джерелаАнотація:
The mulga complex (Acacia aneura and closely related taxa) is a widespread group that is dominant in much of arid Australia. The group is taxonomically difficult, due to a complex interaction of sympatry and putative hybridisation between the major species, geographic variation within species and sympatric variation within A. aneura. Mulga is highly variable in a wide range of vegetative and reproductive characters and it is not unusual to find five or six distinct forms growing side by side. The aim of this project was to gain a better understanding of the relationships among mulga species and A. aneura varieties, as well as the maintenance of this variation. A single site in the Northern Territory, containing A. ayersiana, A. minyura and two varieties of A. aneura, was sampled intensively. Six morphotypes were observed in the field and five were strongly supported by morphometric analysis. Although the mulga complex is generally tetraploid (2n = 52), triploid (2n = 39) and pentaploid (2n = 65) seedlings were produced in the study population. Microsatellite primers developed for A. mangium (sect. Juliflorae) were amplified in individuals of each morphotype, resulting in genetic marker patterns consistent with polyploidy. Genetic and morphometric distances were correlated and differences between morphotypes account for 63% of the total genetic variation (ΦPT = 0.63, P < 0.001). Allele sequences confirmed the presence of genuine heterozygosity and clonality was suggested by the low genotypic diversity and the lack of allele segregation. Seedlings had identical genotypes to the maternal plants and polyembryony was observed in each taxon, consistent with apomictic reproduction. Both variation of the ploidy level and apomixis may restrict gene flow among morphotypes, playing a role in the maintenance of morphological diversity at the study site. The success of the group in arid and semi-arid Australia may also be due, in part, to these factors.
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Page, Gerald F. M., Louise E. Cullen, Stephen van Leeuwen, and Pauline F. Grierson. "Inter- and intra-specific variation in phyllode size and growth form among closely related Mimosaceae Acacia species across a semiarid landscape gradient." Australian Journal of Botany 59, no. 5 (2011): 426. http://dx.doi.org/10.1071/bt11057.
Повний текст джерелаАнотація:
The mulga complex (Acacia aneura F. Muell ex Benth and closely related species) consists of woody trees and shrubs, and is distributed across 20% of the Australian continent. A. aneura is renowned for a wide variety of phyllode shapes and growth forms, which may co-occur at any one site. We examined the intra- and inter-specific variation in growth form and phyllode shape in four species of the mulga complex, including A. aneura, across topographic gradients in semiarid north-west Australia. We measured 792 trees across 28 sites stratified into six discrete landscape positions; upper slope, lower slope, low open woodland, banded woodland, low woodland, and drainage line. Dominance of phyllode shapes was strongly related to landscape position. A. aneura with terete phyllodes were dominant on the hill slopes, whereas broad phyllodes were most common on A. aneura in all valley woodlands. Trends in growth form were less distinct, although single-stemmed forms were more common on hills, whereas the valleys had more multi-stemmed forms. The quantification of growth form and phyllode shape variability within the mulga complex provides a basis for the quantitative determination of functional links between morphology and environmental conditions at both the site and landscape level.
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Leavesley, Adam J., Geoffrey J. Cary, Glenn P. Edwards, and A. Malcolm Gill. "The effect of fire on birds of mulga woodland in arid central Australia." International Journal of Wildland Fire 19, no. 7 (2010): 949. http://dx.doi.org/10.1071/wf09028.
Повний текст джерелаАнотація:
The principal ecosystem driver in arid Australia is unpredictable rainfall, but it is hypothesised that fire also plays an important role in determining the distribution of animals. We investigated the effect of fire on birds in mulga (Acacia aneura) woodland in the central Australian arid zone. The study was conducted at Uluru–Kata Tjuta National Park using 63 sites classified into one of three time-since-fire classes: burnt 2002; burnt 1976; and long-unburnt. Birds were sampled in the winter and spring of 2005 and 2006 and vegetation structure was measured at all sites. Vegetation structure varied with time-since-fire. The burnt 2002 treatment was an early seral stage of mulga woodland and effectively a grassland. The burnt 1976 and long-unburnt treatments were both woodland, but the long-unburnt treatment had greater canopy cover and height. The bird community in the burnt 2002 treatment was characterised by granivores, whereas that in the burnt 1976 and long-unburnt treatments was characterised by foliar insectivores. All species showed monotonic responses to time-since-fire (i.e. none were at significantly highest density in the burnt 1976 treatment). Fire in mulga woodland changed the vegetation structure and consequently also changed the composition of the bird communities.
29
Armstrong, RD, KR Helyar, and EK Christie. "Vesicular-arbuscular mycorrhiza in semi-arid pastures of south-west Queensland and their effect on growth responses to phosphorus fertilizers by grasses." Australian Journal of Agricultural Research 43, no. 5 (1992): 1143. http://dx.doi.org/10.1071/ar9921143.
Повний текст джерелаАнотація:
Field and controlled environment studies were undertaken to determine the seasonal variation in vesicular-arbuscular mycorrhizal (VAM) propagules under different types of vegetation in the mulga (Acacia aneura) shrublands of south-western Queensland and how inoculation with VAM affects the growth and response to phosphorus fertilizers of several grasses common to this region. A most probable number (MPN) technique was used to estimate the number of viable VAM propagules under mulga shrubland and native pasture. There was a pronounced rise in MPN at a native pasture site from June to November, peaking at 1 propagule/g soil, before declining between November and May to non detectable concentrations. In the mulga shrubland site, MPN remained very low (less than 0.2 propagules/g soil) throughout the study. Pasture species in the field were screened for VAM infection in both winter and summer. Only three of the 14 species sampled were infected with VAM in winter (June) after a long drought. In contrast, 10 of the 14 species sampled in December possessed VAM-infected roots. A pot experiment was conducted to examine the influence of VAM inoculation on growth and the response to phosphate fertilizer of several important pasture grasses in pastures derived from mulga shrublands. The treatments comprised a factorial combination of inoculation or non-inoculation with VAM, four grass species (Aristida armata, Cenchms ciliaris cv. USA, Digitaria ammophilla, and Thyridolepis mitchelliana), and four rates of P fertilizer designed to range over very deficient to non-limiting for each species. All species except D. ammophilla produced growth responses to VAM inoculation. Though C. ciliaris and T. mitchelliana responded to VAM inoculation only in soil unamended with P fertilizer, A. amata showed growth responses across all P rates examined, suggesting some factor other than P was limiting this species. The growth response of the grasses to VAM inoculation was poorly correlated with the percentage of root infected with VAM. D. ammophilla had the highest levels of root infection (32%) despite producing no growth response to VAM. In contrast, T. mitchelliana had less than 2% of the root infected with VAM. All species had thin fibrous roots with long (0.35-0.47 mm), frequent root hairs. The differential growth responses to VAM inoculation of A. armata compared with the other grasses may provide a management strategy to control Aristida ingress into pastures established from mulga shrublands.
30
Sinclair, R. "Persistence of dead trees and fallen timber in the arid zone: 76 years of data from the T.G.B. Osborn Vegetation Reserve, Koonamore, South Australia." Rangeland Journal 26, no. 1 (2004): 111. http://dx.doi.org/10.1071/rj04008.
Повний текст джерелаАнотація:
Very little information is available about how long dead trees remain standing, or fallen logs persist, in the Australian arid zone. Data on dead timber longevity were extracted from records of both permanent quadrats and photopoints on the T.G.B. Osborn Vegetation Reserve on Koonamore Station, South Australia. Two species were examined, Acacia aneura (mulga) and Myoporum platycarpum (false sandalwood, sugarwood). Some individuals of mulga are capable of standing dead for over 75 years, while dead M. platycarpum may stand for over 60 years. Dead Myoporum trees remained standing for an average of 31.2 � 5.7 years, fallen trunks persisted for 38.4 � 3.7 years. Standing dead A. aneura persisted on average for 40.0 � 3.7 years, fallen trunks for 22.4� 6.3 years. These figures are almost certainly underestimates. The reasons why are discussed and some comparisons made with temperate forests and tropical mangroves.
31
CODY, MARTIN L. "Mulga bird communities. I. Species composition and predictability across Australia." Australian Journal of Ecology 19, no. 2 (July 28, 2006): 206–19. http://dx.doi.org/10.1111/j.1442-9993.1994.tb00484.x.
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32
Passmore, JGI, and CG Brown. "Property Size and Rangeland Degradation in the Queensland Mulga Rangelands." Rangeland Journal 14, no. 1 (1992): 9. http://dx.doi.org/10.1071/rj9920009.
Повний текст джерелаАнотація:
Small property size is often cited as one of the major causes of rangeland degradation in Australia. However, there is some conjecture as to the importance of this effect and the process by which small property sizes lead to rangeland degradation. Relatively little empirical analysis of these issues has been undertaken, especially in a dynamic context which is all important in the case of rangeland degradation. Regression and dynamic programming techniques are employed in this study to investigate and measure the impact of property sizes on the use and state of one of Australia's most important rangelands, the Queensland mulga rangeland. Regression analysis of cross sectional data reveals significant correlations between property size, stocking rate and degradation. These correlations are confirmed in a normative stochastic dynamic programming model which demonstrates that it is economically optimal for graziers managing smaller properties to adopt higher stocking rates. For these graziers, the longterm costs of land degradation are exceeded by short-term financial benefits of heavier stocking. Thus government policy aimed at arresting the serious degradation occurring in the mulga rangelands should focus on measures to facilitate property build-up..
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Miller, SM, JD Brooker, A. Phillips, and LL Blackall. "Streptococcus caprinus is ineffective as a rumen inoculum to improve digestion of mulga (Acacia aneura) by sheep." Australian Journal of Agricultural Research 47, no. 8 (1996): 1323. http://dx.doi.org/10.1071/ar9961323.
Повний текст джерелаАнотація:
This study examined the distribution of Streptococcus caprinus in domestic and feral ruminants, and the effect of rumen inoculation with S. caprinus on nitrogen digestion in mulga-fed sheep. S. caprinus is a tannin-resistant rumen bacterium found in feral goats and may play a role in alleviating the nutritive depressing effects of high concentrations of plant tannins in these animals. S. caprinus was present in samples of rumen fluid from feral goats and feral camels but was not detectable in rumen fluid from sheep and domestic goats that had not previously grazed forages containing condensed tannins. A proportion of sheep, domestic goats, and cattle grazing in mulga paddocks, with either feral goats or camels, had detectable populations of S. caprinus. Pure cultures of S. caprinus grown in vitro were successfully placed in the rumen of sheep; however, nitrogen digestion was unaffected by rumen inoculation. Interactions between several populations of micro-organisms may therefore be involved in achieving improvements in protein digestion.
34
Hall, W. B., K. G. Rickert, G. M. McKeon, and J. O. Carter. "Simulation studies of nitrogen concentration in the diet of sheep grazing Mitchell and mulga grasslands in western Queensland." Australian Journal of Agricultural Research 51, no. 2 (2000): 163. http://dx.doi.org/10.1071/ar99026.
Повний текст джерелаАнотація:
This study examined the potential to simulate the quality, as indicated by nitrogen concentration, of the diet of sheep grazing the Mitchell and mulga grasslands of western Queensland. Development of this simulation capability will allow pasture growth and animal production models to be more easily coupled. Modifications and optimisation of an existing beef cattle diet selection model, in conjunction with a single sward pasture model, accounted for 69.1% (P < 0.001) and 41.9% (P < 0.001) of variation in sheep dietary nitrogen concentrations observed from grazing trials on Mitchell and mulga grasslands, respectively. Failure to simulate some of the higher recorded dietary nitrogen concentrations was probably associated with high forb content in the diet. Examination of the results indicated that development of pasture growth models which simulate major pasture species, or groups of species (e.g. perennial grasses, annual grasses, browse, forbs, legumes), would appear to be necessary before diet selection models will be better able to explain the variation in dietary quality observed in grazing animals.
35
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.
Повний текст джерелаАнотація:
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.
36
Anderson, VJ, KC Hodgkinson, and AC Grice. "The Influence of Recent Grazing Pressure and Landscape Position on Grass Recruitment in a Semi-Arid Woodland of Eastern Australia." Rangeland Journal 18, no. 1 (1996): 3. http://dx.doi.org/10.1071/rj9960003.
Повний текст джерелаАнотація:
This study examined the effects of previous grazing pressure, position in the landscape and apparent seed trapping capability of soil surface micro-sites on recruitment of the perennial grass Monachather paradoxa (mulga oats) in a semi-arid woodland. Seedling emergence was counted on small plots which had been kept moist for one month. The plots were on bare ground, or at grass tussocks, or at log mounds, sited in the run-off, interception and run-on zones of paddocks that had been grazed for six years at 0.3 and 0.8 sheep equivalent/ha. Few naturally occurring perennial grass seedlings emerged on any of the sites. The level of previous grazing pressure influenced the recruitment of grasses from natural sources as well as from seed of M. paradoxa broadcast on the soil surface; significantly more grass seedlings recruited in paddocks stocked at 0.3 than at 0.8 sheep/ha. Emergence of the sown grass did not differ significantly between the three zones in the landscape, but trends in the data suggest the interception zone may have been the most favourable. Recruitment from in situ grass seed was highest in the mulga grove (run-on) zone. Most seedlings of the sown grass emerged around the bases of existing perennial grass tussocks, but recruitment of volunteer perennial and annual grasses was more evenly distributed between the mulga log-mounds and perennial grass tussocks. It is concluded that very low levels of readily germinable seed of perennial grasses remained in the soil at the end of the drought and that areas with a history of high grazing pressure have less probability of grass recruitment when suitable rain occurs.
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Dastlik, KA, EL Ghisalberti, BW Skelton, and AH White. "Structural Study of (-)-8-Epi-11-nordriman-9-one." Australian Journal of Chemistry 44, no. 1 (1991): 123. http://dx.doi.org/10.1071/ch9910123.
Повний текст джерелаАнотація:
The structure of the title compound (1) has been determined by X-ray crystallographic methods. This compound, not previously described as a natural compound, has been isolated from two varieties of the mulga Acacia aneura. Some points of confusion in the literature regarding spectral parameters assigned to (1) are clarified.
38
Sethi, Moksh, Mark Cook, and Kenneth D. Winkel. "Persistent anosmia and olfactory bulb atrophy after mulga (Pseudechis australis) snakebite." Journal of Clinical Neuroscience 29 (July 2016): 199–201. http://dx.doi.org/10.1016/j.jocn.2015.12.019.
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Jaraula, Caroline M. B., Lorenz Schwark, Xavier Moreau, Walter Pickel, Leon Bagas, and Kliti Grice. "Radiolytic alteration of biopolymers in the Mulga Rock (Australia) uranium deposit." Applied Geochemistry 52 (January 2015): 97–108. http://dx.doi.org/10.1016/j.apgeochem.2014.11.012.
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40
Noble, JC. "Relict Surface-Soil Features in Semi-Arid Mulga (Acacia Aneura) Woodlands." Rangeland Journal 15, no. 1 (1993): 48. http://dx.doi.org/10.1071/rj9930048.
Повний текст джерелаАнотація:
The physical dimensions and locations of two forms of circular surface-soil features, believed to be constructed by animals now locally extinct, are described for a 200 ha site and its environs in a semi- arid mulga (Acacia mura) woodland in north-western New South Wales. The most common were 48 circular (c. 10 m diameter) features, some with well-defined central depressions carrying vigorous grass tussocks. Soil chemical analysis indicated the relatively high fertility of these central depressions. Surface pebbles were analysed for comparison with similar lithological data in the literature. The evidence suggests that the malleefowl (Leipoa ocerlata) is the most likely agent responsible for building these features. While only four of the larger features (c. 30 m diameter) were located in the study site, they were particularly conspicuous on higher ridges in adjoining paddocks because of the abundance of highly reflective, calcrete fragments visible on the surface of subcircular mounds. It is postulated that they were constructed by the bumowing bettong (Bettongia lesueur).
41
Pritchard, DA, PR Martin, and PK O'Rourke. "The role of condensed tannins in the nutritional value of mulga (Acacia aneura) for sheep." Australian Journal of Agricultural Research 43, no. 8 (1992): 1739. http://dx.doi.org/10.1071/ar9921739.
Повний текст джерелаАнотація:
Sheep were fed mulga (Acacia aneura) ad libitum and supplemented with 0, 12 or 24 g/day of polyethylene glycol molecular weight 4000 (PEG), with or without an additional supplement of 1.5 g/day of each of nitrogen (N), phosphorus (P) and sulfur (S) (NPS). Supplementation with either 12 g/day PEG or 24 g/day PEG increased dry matter intake by 56 and 78% respectively and clean wool growth per unit surface area by 166 and 178% respectively. Supplementation with 24 g/day PEG increased wool fibre diameter, linear growth rate and volumetric growth rate by 32, 29 and 143% respectively. Sheep receiving 24 g/day PEG retained more N (1.80 g/day) and S (254 mg/day) and digested more N (218 g/kg) and S (229 g/kg) when compared with non-supplemented animals. These parameters were further enhanced when NPS was supplemented in conjunction with 24 g/day PEG. Maximum precipitation (77%) of mulga condensed tannins (CT) occurred at a PEG to CT ratio of 0.7:l.
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Anderson, VJ, RB Hacker, and KC Hodgkinson. "Photographic Utilisation Standards for Three Perennial Grasses." Rangeland Journal 16, no. 1 (1994): 135. http://dx.doi.org/10.1071/rj9940135.
Повний текст джерелаАнотація:
Height-weight profiles were established for Monachather paradoxa, Thyridolepis rnitchelliana and Eragrostis eriopoda based on field populations from semi-arid mulga woodlands in north-western New South Wales. These profiles were subsequently used to develop photographic standards of percentage canopy remaining by weight as a guide to field assessment of the severity of grazing. Examples of the standards are presented.
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TONGWAY, D. J., and J. A. LUDWIG. "Vegetation and soil patterning in semi-arid mulga lands of Eastern Australia." Austral Ecology 15, no. 1 (March 1990): 23–34. http://dx.doi.org/10.1111/j.1442-9993.1990.tb01017.x.
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Griessmann, Martin, Andreas Schmidt Mumm, Thomas Seifert, and Colin Conor. "The Mt. Mulga barite–magnetite–copper–gold mineralisation, Olary Domain, South Australia." Journal of Geochemical Exploration 106, no. 1-3 (July 2010): 110–20. http://dx.doi.org/10.1016/j.gexplo.2009.11.008.
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Mack, Charlotte L., and Lynne A. Milne. "Eocene palynology of the Mulga Rocks deposits, southern Gunbarrel Basin, Western Australia." Alcheringa: An Australasian Journal of Palaeontology 39, no. 4 (April 13, 2015): 444–58. http://dx.doi.org/10.1080/03115518.2015.1022090.
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Thakshila, Prabhani, Wayne C. Hodgson, Geoffrey K. Isbister, and Anjana Silva. "In Vitro Neutralization of the Myotoxicity of Australian Mulga Snake (Pseudechis australis) and Sri Lankan Russell’s Viper (Daboia russelii) Venoms by Australian and Indian Polyvalent Antivenoms." Toxins 14, no. 5 (April 26, 2022): 302. http://dx.doi.org/10.3390/toxins14050302.
Повний текст джерелаАнотація:
We studied the neutralisation of Sri Lankan Russell’s viper (Daboia russelii) and Australian mulga snake (Pseudechis australis) venom-induced myotoxicity by Indian (Vins and Bharat) and Australian (Seqirus) polyvalent antivenoms, using the in vitro chick biventer skeletal muscle preparation. Prior addition of Bharat or Vins antivenoms abolished D. russelii venom (30 µg/mL)-mediated inhibition of direct twitches, while Australian polyvalent antivenom was not protective. Bharat antivenom prevented, while Vins and Australian polyvalent antivenoms partially prevented, the inhibition of responses to exogenous KCl. Myotoxicity of Mulga venom (10 µg/mL) was fully neutralised by the prior addition of Australian polyvalent antivenom, partially neutralised by Vins antivenom but not by Bharat antivenom. Although the myotoxicity of both venoms was partially prevented by homologous antivenoms when added 5 min after the venom, with an increasing time delay between venom and antivenom, the reversal of myotoxicity gradually decreased. However, antivenoms partially prevented myotoxicity even 60 min after venom. The effect of antivenoms on already initiated myotoxicity was comparable to physical removal of the toxins by washing the bath at similar time points, indicating that the action of the antivenoms on myotoxicity is likely to be due to trapping the toxins or steric hindrance within the circulation, not allowing the toxins to reach target sites in muscles.
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Thakshila, Prabhani, Wayne C. Hodgson, Geoffrey K. Isbister, and Anjana Silva. "In Vitro Neutralization of the Myotoxicity of Australian Mulga Snake (Pseudechis australis) and Sri Lankan Russell’s Viper (Daboia russelii) Venoms by Australian and Indian Polyvalent Antivenoms." Toxins 14, no. 5 (April 26, 2022): 302. http://dx.doi.org/10.3390/toxins14050302.
Повний текст джерелаАнотація:
We studied the neutralisation of Sri Lankan Russell’s viper (Daboia russelii) and Australian mulga snake (Pseudechis australis) venom-induced myotoxicity by Indian (Vins and Bharat) and Australian (Seqirus) polyvalent antivenoms, using the in vitro chick biventer skeletal muscle preparation. Prior addition of Bharat or Vins antivenoms abolished D. russelii venom (30 µg/mL)-mediated inhibition of direct twitches, while Australian polyvalent antivenom was not protective. Bharat antivenom prevented, while Vins and Australian polyvalent antivenoms partially prevented, the inhibition of responses to exogenous KCl. Myotoxicity of Mulga venom (10 µg/mL) was fully neutralised by the prior addition of Australian polyvalent antivenom, partially neutralised by Vins antivenom but not by Bharat antivenom. Although the myotoxicity of both venoms was partially prevented by homologous antivenoms when added 5 min after the venom, with an increasing time delay between venom and antivenom, the reversal of myotoxicity gradually decreased. However, antivenoms partially prevented myotoxicity even 60 min after venom. The effect of antivenoms on already initiated myotoxicity was comparable to physical removal of the toxins by washing the bath at similar time points, indicating that the action of the antivenoms on myotoxicity is likely to be due to trapping the toxins or steric hindrance within the circulation, not allowing the toxins to reach target sites in muscles.
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Leavesley, Adam J., and Geofferey J. Cary. "The effect of patch area on birds in central Australian mulga (Acacia aneura) woodland of different times-since-fire." Pacific Conservation Biology 19, no. 1 (2013): 28. http://dx.doi.org/10.1071/pc130028.
Повний текст джерелаАнотація:
It is often assumed that a fine-scaled mosaic of different times-since-fire supports greater biodiversity than a coarsescaled mosaic — the fire mosaic hypothesis. A potential mechanism of the fire mosaic hypothesis is the effect of area on species diversity. We investigated the effect of patch area on bird communities in mulga (Acacia aneura) woodland in central Australia. The study was conducted at Uluru Kata-Tjuta National Park using 55 fixed-area sites classified to the time since last fire: burnt 2002; burnt 1976 and long unburnt. Birds were surveyed in the winter and spring of 2005 and 2006. Of 20 key species, two showed a positive density-area effect (i.e. higher density in larger patches). Patch area did not affect total bird density or species richness. However, species turnover (ß-diversity) was greater in large patches in the burnt 2002 treatment than it was in small patches. There was no effect of patch area on the composition of the bird communities in any of the time-since-fire classes. We concluded that patch area did affect the distribution of some birds in mulga woodland. However, patch area was not a mechanism of the fire mosaic hypothesis because the effects of patch size tended to increase avian diversity in larger patches rather than small.
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Armstrong, RD, and KR Helyar. "Relative importance of soil phosphorus to the growth of wiregrass (Aristida armata) compared with other grasses common to the mulga shrublands of Queensland." Australian Journal of Experimental Agriculture 33, no. 3 (1993): 337. http://dx.doi.org/10.1071/ea9930337.
Повний текст джерелаАнотація:
The influence of phosphorus (P) applied to mulga topsoil on the growth of Aristida amata, Cenclirus ciliaris, Digitaria ammophila, and Thyridolepis mitchelliana was examined in2 glasshouse trials, to test the hypothesis that the invasion of A. amata into mulga shrublands may result from a superior ability to exploit and utilise soil P compared to the other grasses.Growth of all grasses was poor without added P, and all grasses produced large growth responses to added P. In contrast to the other native grasses, A. armata required as much added P as the exotic C. ciliaris to achieve maximum growth. The ability of the grasses to grow without added P was related more to an ability to absorb P than to differences in internal requirements. With no P added, T. mitchelliana had the highest P absorption rate (�g P/g root.day), followed by A. amata, C. ciliaris, and D. ammophila. Adding P reversed this order. Cenchrus ciliaris and D. ammophila had the highest relative growth rates of shoots during early growth stages, especially with P added. Although A amata had a greater ability than C. ciliaris to access and utilise soil P at low P concentrations, there was no evidence that it was superior to the other native grasses.
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Davies, S. J. J. F., S. A. Kenny, and T. F. M. Walsh. "The population dynamics of some arid zone plants during 46 years of grazing on Mileura Station, Western Australia." Rangeland Journal 37, no. 4 (2015): 367. http://dx.doi.org/10.1071/rj15016.
Повний текст джерелаАнотація:
Grazed quadrats were monitored on Mileura Station, Western Australia from 1967 to 2013 in order to study the population dynamics of the perennial plants in two of the land systems on the property. Counts of plants on four quadrats at each of 10 sites were made in 1967, 1976, 1990 and 2013, and individual plants were traced for the first three samplings. Five sites were on the Sherwood land system and five on the Belele land system. The results indicated that the populations of some species in the mulga shrubland increased steadily over the 46 years of the study whereas the populations of other species, especially the small, short-lived shrubs, fluctuated over this period. A reduction in stocking rate from 1976 to 1990 was associated with an increase in the population of perennial plants; the total numbers for the 1976 count were 1506 compared with 2102 in 1990. Mean summer rainfall increased between 1990 and 2013 and this increase may have been associated with the recruitment. Overall, the study showed that commercial stocking, although at a lower rate than that recommended by the Western Australian Department of Agriculture, was compatible with increases in the populations of the perennial components of mulga shrubland in this region.