Altitudinal Variation in the Photosynthetic Characteristics of Snow Gum, Eucalyptus pauciflora Sieb. Ex Spreng. I. Seasonal Changes Under Field Conditions in the Snowy Mountains Area of South-Eastern Australia

1977 ◽  
Vol 25 (1) ◽  
pp. 1 ◽  
Author(s):  
RO Slayter ◽  
PA Morrow
Keyword(s):  
Seasonal Changes ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Characteristics ◽  
Maximum Temperature ◽  
Seasonal Temperature ◽  
South Eastern ◽  
Eastern Australia ◽  
Significant Difference ◽  
South Eastern Australia

A field study of seasonal changes in the photosynthetic characteristics of three altitudinal populations of the snow gum (Eucalyptus pauciflora Sieb. ex. Spreng) was conducted at elevations of 915, 1215 and 1645 m in the Snowy Mountains area of south-eastern Australia. At optimal temperatures in midsummer, peak rates of photosynthesis under CO2-saturating conditions (Psub) reached levels of 125-135 ng cm-2 sec-1, and under ambient CO2 conditions (Pamb) reached levels of 45-55 ng cm-2 sec-1. Corresponding values of the intracellular resistance to CO2 transfer (ri) were 5-6 sec cm-1, and of the gas phase resistance to water-vapour transfer (r,) 1.2-2 sec cm-1. Measured at temperatures of 15, 20 and 25°C, the peak seasonal values of Pmax showed no significant difference between sites, but at 5° and 10° peak values were highest at the highest elevation (coldest site), and at 30° and 35° peak values were highest at the lowest elevation (warmest site). Generally similar patterns applied to Paamb. These features are consistent with the view that E. Pauciflora shows continuous variation in many physiological characteristics over its altitudinal range. At each site the temperature optimum for photosynthesis changed markedly during the season, and was closely correlated both with the long-term maximum air temperature and with the mean maximum temperature of the 10 days prior to the date of measurement. This appeared to reflect long-term adaptation of the photosynthetic apparatus of each population to the general temperature conditions at each site, combined with a short-term acclimation to the prevailing seasonal temperature regime.

Crop responses to lime in long-term pasture-crop rotations in a high rainfall area in south-eastern Australia

2001 ◽  
Vol 52 (3) ◽  
pp. 329 ◽  
Author(s):  
G. D. Li ◽  
K. R. Helyar ◽  
M. K. Conyers ◽  
B. R. Cullis ◽  
P. D. Cregan ◽  
...  
Keyword(s):  
Crop Production ◽  
Acid Soils ◽  
Crop Rotations ◽  
Severe Drought ◽  
High Rainfall ◽  
South Eastern ◽  
Permanent Pasture ◽  
Eastern Australia ◽  
South Eastern Australia

A long-term trial, known as ‘managing acid soils through efficient rotations’ (MASTER), commenced in 1992 to develop and demonstrate a cropping system that is economically viable on the highly acid soils of the traditional permanent pasture region in south-eastern Australia, so that their fertility is sustained or improved. There were 2 permanent pasture systems and 2 pasture–crop rotations, each with and without lime. This paper reports the effect of lime on crop production over the first cycle (6 years). On annual pasture–crop rotations, lime significantly increased the dry matter production at anthesis and grain yields of wheat (cv. Dollarbird) compared with the unlimed treatments. Averaged across years from 1992 to 1997 (excluding the severe drought year 1994), wheat crops produced 1.6 t/ha more grain on the limed treatments than on the unlimed treatments (3.6 v. 2.0 t/ha). On perennial pasture–crop rotations, the lime effects varied with crops grown at each phase and year. For example, despite being tolerant of acidity, oats (cv. Yarran) responded to lime in 1996. Likewise, triticale (cv. Abacus) responded to lime in 1997. Wheat (cv. Dollarbird) that is moderately tolerant to acidity responded to lime in phase 6 from 1992 to 1997 excluding 1994 (3.5 v. 1.7 t/ha). Acid-tolerant wheat varieties, triticale, and narrow-leaf lupins are considered the most viable crops for the soil and climatic conditions encountered in this high rainfall (5000—800 mm per annum) area of south-eastern Australia.

Pasture and sheep responses to lime application in a grazing experiment in a high-rainfall area, south-eastern Australia. II. Liveweight gain and wool production

2006 ◽  
Vol 57 (10) ◽  
pp. 1057 ◽  
Author(s):  
G. D. Li ◽  
K. R. Helyar ◽  
M. K. Conyers ◽  
L. J. C. Castleman ◽  
R. P. Fisher ◽  
...  
Keyword(s):  
Rotation Period ◽  
Acid Soils ◽  
Pasture Production ◽  
Wool Production ◽  
South Eastern ◽  
Eastern Australia ◽  
Lime Application ◽  
High Rainfall Area ◽  
South Eastern Australia

‘Managing Acid Soils Through Efficient Rotations (MASTER)’ is a long-term pasture–crop rotation experiment commenced in 1992. One of the objectives was to demonstrate the extent of crop, pasture, and animal responses to lime application on a typical acidic soil in the 500–800 mm rainfall zone of south-eastern Australia. Two types of pastures (perennial v. annual pastures) with or without lime application were established in 1992. Fifteen- to eighteen-month-old Merino hoggets were used as test animals and were changed annually. This paper reports the results of sheep responses to liming from the 4 continuous pasture treatments over 6 years from 1992 to 1997. The stocking rate was the same on all plots within a treatment during each rotation period, but was varied between treatments based on the pasture availability and sheep body condition. The most important findings from this study are that the limed treatments carried 29% and 27% more stock (up to 4 DSE/ha) than the unlimed treatments for perennial and annual pastures, respectively. As a result, the limed perennial pastures produced 27% more liveweight gain (62 kg/ha.year) and 28% more greasy wool (13 kg/ha.year) than unlimed perennial pastures, whereas the limed annual pastures produced 34% more liveweight gain (77 kg/ha.year) and 24% more greasy wool (11 kg/ha.year) than unlimed annual pastures. The significant responses to lime in liveweight and wool production were detected from the second growing season after the pastures were established. The increased sheep productivity on the limed treatment was due to a combination of increased pasture production and improved pasture quality. Perennial pastures showed a slight advantage in wool production, but not in liveweight gain. However, the seasonal variation of liveweight was greater on annual pastures than on perennial pastures. The larger variation in liveweight change could lead to more adverse effects on wool quality especially at high grazing pressures. Grazing management can be used to manipulate pasture and animal productivity to increase profits from lime use.

Utilization of Appetite for Sodium Salts to Control Rabbit Populations by Poisoning.

1975 ◽  
Vol 2 (2) ◽  
pp. 135 ◽  
Author(s):  
K Myers
Keyword(s):  
Sodium Chloride ◽  
Early Summer ◽  
Effective Control ◽  
Sodium Salts ◽  
Control Rabbit ◽  
South Eastern ◽  
Eastern Australia ◽  
Bait Stations ◽  
South Eastern Australia

Rabbits in subalpine areas in south-eastern Australia show a marked avidity for sodium salts during the spring and early summer months. During that period rabbit populations may be controlled by allowing access to soft wooden meranti pegs impregnated with sodium chloride and sodium luoroacetate (poison 1080). If the pegs are left out as permanent bait stations they produce long-term effective control. The method should be applicable to other areas in Australia where soil sodium is very low.

The population ecology of the squirrel glider (Petaurus norfolcensis) within a network of remnant linear habitats

2002 ◽  
Vol 29 (4) ◽  
pp. 329 ◽  
Author(s):  
Rodney van der Ree
Keyword(s):  
Agricultural Landscape ◽  
South Eastern ◽  
Linear Habitats ◽  
Continuous Forest ◽  
Eastern Australia ◽  
Squirrel Glider ◽  
Density Population ◽  
Natality Rate ◽  
South Eastern Australia

The geographic range of the squirrel glider (Petaurus norfolcensis) in south-eastern Australia largely corresponds with fertile soils highly suited for agriculture. As a consequence of extensive clearing for agriculture, the conservation of P. norfolcensis in south-eastern Australia is now reliant on a mosaic of many fragmented and isolated patches of woodland and forest. In this study, I investigated the population dynamics of P. norfolcensis in an agricultural landscape where most remnant woodland occurs as linear strips along roadsides, unused road reserves and watercourses. A total of 251 gliders were trapped 1343 times within the linear habitats between December 1996 and November 1998. Gliders were resident within the linear strips at 0.95–1.54 individuals ha–1, a density equal to, or greater than, that recorded elsewhere for the species in continuous forest. All adult females were reproductively active and the mean natality rate was 1.9 young per adult female per year. Overall, the population age-structure appeared to be stable. While currently supporting a stable, high-density population, the long-term viability of these remnants as habitat is not assured because roadside reserves are narrow, easily fragmented and subjected to a host of deleterious processes causing ongoing habitat loss and degradation.

The rise and fall of a translocated population of the endangered Macquarie perch, Macquaria australasica, in south-eastern Australia

2013 ◽  
Vol 64 (9) ◽  
pp. 838 ◽  
Author(s):  
Mark Lintermans
Keyword(s):  
Single Individual ◽  
Spawning Habitat ◽  
Management Activity ◽  
South Eastern ◽  
Millennium Drought ◽  
Eastern Australia ◽  
Term Monitoring ◽  
South Eastern Australia

Translocation is an increasingly popular conservation management activity worldwide, but the success of translocation is often not measured or reported. A population of the endangered Macquarie perch was imperilled by the damming in 1977 of the Queanbeyan River, near Canberra in south-eastern Australia. In November 1980, 66 adult Macquarie perch (309–389-mm total length) individuals were collected from the newlyformed reservoir, and translocated approximately 4 km upstream into the Queanbeyan River past a waterfall (which prevented access to spawning habitat). Five years of post-translocation monitoring at the release sites resulted in the capture of only a single individual in late 1981. Consequently, monitoring ceased because the translocation was assumed to have failed. However, subsequent angler reports and a preliminary survey in 1991 confirmed that some translocated fish had survived, and a small recruiting population had established. More intensive follow-up surveys and subsequent monitoring from 1996 to 2006 demonstrated an established population with consistent recruitment until 2001. However, after 2001, there was no evidence of recruitment and the population is now undetectable, with the prolonged ‘millennium drought’ (1997–2010) being the most plausible cause. The present study demonstrates the potentially ephemeral nature of assessments of success and failure, and the importance of targeted long-term monitoring programs.

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