scholarly journals Spatial and temporal effects of grazing management and rainfall on the vertebrate fauna of a tropical savanna

2012 ◽  
Vol 34 (2) ◽  
pp. 173 ◽  
Author(s):  
A. S. Kutt ◽  
E. P. Vanderduys ◽  
P. O'Reagain

Grazing by domestic livestock is one of the most widespread uses of the rangelands of Australia. There is limited information on the effects of grazing by domestic livestock on the vertebrate fauna of Australia and the establishment of a long-term grazing experiment in north-eastern Queensland at Wambiana provided an opportunity to attempt an examination of the changes in vertebrate fauna as a consequence of the manipulation of stocking rates. The aim was to identify what the relative effects of vegetation type, stocking rate and other landscape-scale environmental factors were on the patterns recorded. Sixteen 1-ha sites were established within three replicated treatments (moderate, heavy and variable stocking rates). The sites were sampled in the wet and dry seasons in 1999–2000 (T0) and again in 2003–04 (T1). All paddocks of the treatments were burnt in 1999. Average annual rainfall declined markedly between the two sampling periods, which made interpretation of the data difficult. A total of 127 species of vertebrate fauna comprising five amphibian, 83 bird, 27 reptile and 12 mammal species were recorded. There was strong separation in faunal composition from T0 to T1 although changes in mean compositional dissimilarity between the grazing stocking rate treatments were less well defined. There was a relative change in abundance of 24 bird, four mammal and five reptile species from T0 to T1. The generalised linear modelling identified that, in the T1 data, there was significant variation in the abundance of 16 species explained by the grazing and vegetation factors. This study demonstrated that vertebrate fauna assemblage did change and that these changes were attributable to the interplay between the stocking rates, the vegetation types on the sites surveyed, the burning of the experimental paddocks and the decrease in rainfall over the course of the two surveys. It is recommended that the experiment is sampled again but that the focus should be on a rapid survey of abundant taxa (i.e. birds and reptiles) to allow an increase in the frequency of sampling and replication of the data. This would help to articulate more clearly the trajectory of vertebrate change due to the relative effects of stocking rates compared with wider landscape environmental changes. Given the increasing focus on pastoral development in northern Australia, any opportunity to incorporate the collection of data on biodiversity into grazing manipulation experiments should be taken for the assessment of the effects of land management on faunal species.

2003 ◽  
Vol 43 (8) ◽  
pp. 945 ◽  
Author(s):  
P. Sanford ◽  
B. R. Cullen ◽  
P. M. Dowling ◽  
D. F. Chapman ◽  
D. L. Garden ◽  
...  

The Sustainable Grazing Systems (SGS) National Experiment (NE) Pasture Theme explored factors that influenced annual herbage accumulation and perennial grass and legume content across the NE sites, in the high rainfall zone (HRZ, >600 mm/year annual rainfall) of southern Australia using multi-variate analysis and the SGS Pasture Model. Annual rainfall was a poor predictor of annual herbage accumulation. The length of growing season accounted for 30% of the variation in annual herbage accumulation. Much of the remaining 70% of variation in annual herbage accumulation was explained by soil Olsen P, the proportion of native species in the pasture and stocking rate, together with interactions among other factors including legume content. Simulated effects of set stocking and rotational grazing on herbage accumulation using the SGS Pasture Model, predicted that rotational grazing was unlikely to result in large increases in herbage accumulation. In contrast, it was predicted that the adoption of deep-rooted C3 and C4 perennial grasses could provide useful increases in herbage accumulation. Perennial grass content and basal cover were both significantly influenced by growing season length (P<0.001), grazing method (P<0.001) and an interaction between stocking rate and soil pH (P = 0.002). These analyses suggested that to maintain or improve the perennial grass component of a pasture at medium–high stocking rates, it was crucial to adopt grazing strategies that included rotation or resting. Perennial grass percent also significantly (P<0.001) increased in response to ameliorating the soil pH. Legume content of pastures significantly (P<0.001) increased in response to set stocking and increased stocking rate.To be botanically stable and productive, sown pastures based on perennial grasses in the HRZ of southern Australia will need to be grazed at high stocking rates (15–23 DSE/ha) in combination with rotational grazing or resting, and with adequate soil P. Additional gains in production and stability could be obtained by ensuring an adequate legume component, including a C4 perennial grass and ameliorating soil acidity. Pastures based on native perennial grasses may require lower soil P and more conservative stocking rates, depending on species.


Author(s):  
B.E. Allan

Continuous stocking was compared with intermittent (two paddock) and rotational (six paddock) grazing at low, medium and high stocking rates equivalent to 1.0x, 1.5x and 2.0x conventional rates for oversown tussock country (500 mm annual rainfall). 'By the sixth year liveweight gain/ha from Merino wether hoggets was improved 26% by intermittent and rotational grazing at medium stocking rates from that at conventional stocking rates. A strong interaction was demonstrated, with advantage in liveweight gain from intermittent and rotational grazing strengthening with increasing stocking rate. Total vegetative cover (75.8%) remained unchanged. Cocksfoot increased under low stocking while ryegrass increased under high stocking. A 60% overall loss in ryegrass during 1982 was attributed to unusually low winter soil temperatures. White clover cover was affected more b y climate than by grazing. A!!hough ?here *were interim differences, herbage production by the sixth year was similar for all treatments. Keywords: Tussock country, oversown, grazing, stocking rate, subdivision, pasture development, utilisation, Merino, liveweight.


Author(s):  
J. Hodgson

Recent assessments of the relative importance of stocking rate. stocking policy and grazing management on the output from pastoral systems are used as a starting point to argue the need for objective pasture assessments to aid control of livestock enterprises to meet production targets. Variations in stocking rates, stocking policy and other management practices all provide alternative means of control of pasture conditions which are the major determinants of pasture and animal performance. Understanding of the influence of pasture conditions on systems performance should provide a better basis for management control and for Communication between farmers, extension officers and researchers. Keywords: Stocking rate, pasture condition, pasture cover


2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 27-27
Author(s):  
Jane A Parish ◽  
Kalisha C Yankey ◽  
Libby S Durst

Abstract Optimal use of native warm-season grasses in pasture systems involves stocking grazing livestock at suitable rates. The study objective was to evaluate forage nutritive value and heifer ADG at two stocking rates on mixed-sward pastures of big bluestem (Andropogon gerardi Vitman), little bluestem (Andropogon scoparius), and indiangrass (Sorghastrum nutans L.). Pastures (3 replications) were stocked for 56 d during June and July in 2 yr with crossbred (Bos taurus) heifers (n = 24 heifers/year) stratified by initial BW (288.3 ± 1.7 kg) to one of two continuous stocking rates: 1.9 heifers/ha (HIGH) and 1.2 heifers/ha (LOW). Mean forage nutritive values on a DM basis were not different between HIGH and LOW stocking rates, respectively, for CP (7.0 ± 0.2% vs 6.7 ± 0.2%; P = 0.27), ADF (41.0 ± 0.6 vs. 41.4 ± 0.6; P = 0.64), NDF (69.9 ± 0.5 vs. 68.7 ± 0.5; P = 0.09), or relative feed value (RFV) (76.0 ± 1.0 vs. 76.9 ± 1.0; P = 0.53). There was a year effect (P &lt; 0.01) and stocking rate x day effect (P &lt; 0.01) for TDN. At LOW, TDN decreased from day 0 to day 28 (P = 0.02) and day 28 to day 56 (P = 0.02). At HIGH, TDN decreased (P &lt; 0.01) from day 0 to day 28 but remained steady until day 56 (P = 0.21). There was a stocking rate x day interaction (P &lt; 0.01) with ADG: LOW day 28 to 56 (1.20 ± 0.08 kg/day), HIGH day 0 to 28 (0.89 ± 0.08 kg/day), HIGH day 28 to 56 (0.44 ± 0.08 kg/day), and LOW day 0 to 28 (0.30 ± 0.08 kg/day). Further assessment of cattle ADG using more divergent stocking rates and plant persistence measures is warranted to inform ideal native grass stocking rate recommendations.


1977 ◽  
Vol 28 (1) ◽  
pp. 133 ◽  
Author(s):  
JP Langlands

Grass and milk consumption and liveweight changes of lambs grazed at stocking rates ranging from 9 to 35 sheep/ha were measured during a 105 day lactation. Grass consumption and wool production of their mothers and of similar ewes without lambs were also determined. The forage and total organic matter intakes of the lamb increased with time while milk consumption declined; all three variables were negatively correlated with stocking rate. The intake of the ewe and its liveweight gain were not sensitive to increasing stocking rate, but wool production declined at higher stocking rates. The maintenance requirement of the ewes was estimated to be 218 kJ metabolizable energy/kg liveweight, and the efficiency with which metabolizable energy was utilized for milk production was 66%. Lactation increased the intake of the ewe but reduced its wool production.


Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1078
Author(s):  
Christopher Brock ◽  
Meike Oltmanns ◽  
Christoph Matthes ◽  
Ben Schmehe ◽  
Harald Schaaf ◽  
...  

Mixed-crop-livestock farms offer the best conditions for sustainable nutrient management in organic farming. However, if stocking rates are too low, sustainability might be threatened. Therefore, we studied the development of soil organic matter and nutrients as well as crop yields over the first course of a new long-term field experiment with a mimicked cattle stocking rate of 0.6 LU ha−1, which is the actual average stocking rate for organic farms in Germany. In the experiment, we tested the effects of additional compost application to improve organic matter supply to soils, and further, potassium sulfate fertilization for an improved nutrition of fodder legumes. Compost was made from internal resources of the farm (woody material from hedge-cutting). Soil organic matter and nutrient stocks decreased in the control treatment, even though yield levels, and thus nutrient exports, were comparably low. With compost application, soil organic matter and nutrient exports could be compensated for. At the same time, the yields increased but stayed at a moderate level. Potassium sulfate fertilization further improved N yields. We conclude that compost from internal resources is a viable solution to facilitate sustainable organic crop production at low stocking rates. However, we are aware that this option does not solve the basic problem of open nutrient cycles on the farm gate level.


1968 ◽  
Vol 71 (3) ◽  
pp. 327-335 ◽  
Author(s):  
J. B. Owen ◽  
W. J. Ridgman

SUMMARYExperiments designed to assess differences between treatments in pasture productivity as measured by the production of animals are complicated by the stocking rates chosen. The paper attempts toderive a simple model relating production per animal and production per unit area to stocking rate for meat animals, based on biological considerations.A method is proposed which would allow meaningful grazing experiments to be carried out employing only one stocking rate, thus considerably reducing the expense of this type of experimentation.The model is applied to some recent data obtained by Hodgson (1966) and Appleton (1967, personal communication).


1979 ◽  
Vol 19 (97) ◽  
pp. 140 ◽  
Author(s):  
EJ Bowen ◽  
KG Rickert

At Gayndah, south-eastern Queensland, a native Heteropogon contortus pasture, sown to fine-stem stylo (Stylosanthes guianensis var. intermedia), and invaded by red natal grass (Rhynchelytrum repens), was grazed by weaner steers from June 1 in three treatments : heavy and light put-and-take grazing for five years from 1971, and set-stocked at 1.37 animals ha-1 for two years from 1974. Weight gains in the put-and-take treatments were not significantly different. The mean annual liveweight gain was 167 kg animal-1 at a mean equivalent stocking rate of 1.47 animals ha-1. Over the same period unsown native pasture, cleared of timber, gave a gain of 62 kg animal-1 at 0.62 animals ha-1. In all seasons except summer, weight gains declined linearly with stocking rate and in 1972-73, with a mean equivalent stocking rate of 2.66 animals ha-1, the annual gain was almost halved. When equivalent stocking rates were 0.9, 0.9, 1.8 and 1.2 animals ha-1 in winter, spring, summer and autumn, the respective gains were 4, 73, 65 and 45 kg animal-1. The set-stocked treatment had a mean annual gain of 147 kg animal-1. At another site 116 km north-west of Gayndah, two paddocks of Heteropogon contortus and fine-stem stylo were set-stocked with weaners over four years. One paddock had four applications of superphosphate of 250 kg ha-1. The mean annual liveweight gains were significantly different, being 154 and 143 kg animal-1 in the fertilized and unfertilized paddocks at mean stocking rates of 0.83 and 0.74 animals ha-1, respectively. In a grazing protection experiment the density of fine-stem stylo declined exponentially with an accumulation of pasture dry matter in spring and summer. Heavy continuous grazing, an annual hay cut and an accidental fire all increased the density of fine-stem stylo. Management options to maintain the density of fine-stem stylo and the relative importance of the legume and grass to animal production are discussed.


1997 ◽  
Vol 128 (3) ◽  
pp. 339-346 ◽  
Author(s):  
D. T. CHONG ◽  
I. TAJUDDIN ◽  
Abd. M. S. SAMAT ◽  
W. W. STÜR ◽  
H. M. SHELTON

The productivity of grazing sheep was assessed under 7-year-old rubber at the Rubber Research Institute of the Malaysia Experimental Station at Sungai Buloh near Kuala Lumpur between October 1988 and May 1990. The sheep were Dorset × Marlin crossbred lambs and they grazed planted leguminous cover crops and naturally occurring species at a range of stocking rates.In the immature rubber trial, presentation yields of forage declined with time regardless of stocking rate. In the mature rubber trial, presentation yields of forage were low (<1000 kg/ha) due to low light transmission. High stocking rates (>6 sheep/ha) resulted in a decrease in the proportion of palatable species, namely Pueraria phaseoloides, Paspalum conjugatum, Asystasia gangetica and Mikania micrantha and an increase in the proportion of the less palatable species such as Calopogonium caeruleum and Cyrtococcum oxyphyllum.Daily liveweight gains ranged from 100 g/lamb per day at 4 sheep/ha to 70 g/lamb per day at 14 sheep/ha in the immature rubber trial. Only the lowest stocking rate of 2 sheep/ha was continuously sustainable in the mature rubber trial. The estimated maximum liveweight gain that could be achieved under immature rubber was 266 kg/ha per year at a stocking rate of 13·2 sheep/ha.


1983 ◽  
Vol 101 (1) ◽  
pp. 1-7 ◽  
Author(s):  
A. Pott ◽  
L. R. Humphreys

SUMMARYSheep were grazed for 2 years at stocking rates of 7, 14, 21 and 28/ha on a pasture comprising Lotononis bainesii and Digitaria decumbens cv. Pangola at Mt Cotton, south–east Queensland. There were six replicates of each treatment grazed in rotation with 3 days' grazing followed by 15 days' rest.The initial dominance of lotononis was lost after 6 months of grazing and lotononis failed to persist satisfactorily at any stocking rate. Demographic studies showed that lotononis behaved as a short-lived plant, predominantly annual, with some vegetative perennation as stolon-rooted units under heavy grazing. Soil seed reserves varied from 5800 to 400 m2 at the lightest and heaviest stocking rates respectively. Lotononis failed to regenerate under Pangola shading or inopportune high grazing pressure. Soil bulk density (0–7 cm) increased from 1·2 to 1·4 g/cm3 according to stocking rate.


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