Aspects of the biology of the European rabbit (Oryctolagus cuniculus) and rabbit haemorrhagic disease virus (RHDV) in coastal eastern Australia

2007 ◽  
Vol 34 (5) ◽  
pp. 398 ◽  
Author(s):  
B. J. Richardson ◽  
S. Phillips ◽  
R. A. Hayes ◽  
S. Sindhe ◽  
B. D. Cooke
Keyword(s):  
Breeding Season ◽  
Population Biology ◽  
Late Summer ◽  
European Rabbit ◽  
Annual Rainfall ◽  
Factors Affecting ◽  
High Rainfall ◽  
Eastern Australia ◽  
Rabbit Haemorrhagic Disease ◽  
High Rainfall Area

A population of wild rabbits in a high-rainfall area near Sydney, New South Wales, was studied for 8 years to investigate the population biology of the rabbit in a high-rainfall area, to examine factors affecting the length of the breeding season, and to describe the biology of RHDV and a RHDV-like virus in the population. The breeding season was short, starting in June and ending in October, though some conceptions occurred in every month of the year. Supplementary feeding with grain, germinated wheat or high-protein rabbit pellets did not extend the breeding season, so predictions that the length of the breeding season and occurrence of anaemia were influenced by a lack of protein in the diet were not upheld. Myxomatosis appeared in late summer each year as in inland southern Australia. Studies of the immunostatus of the population showed that, even in the years before RHDV was released in Australia, 80–100% of adult animals were seropositive when tested with ELISA specifically designed to detect antibodies to RHDV, arguably owing to the presence of a RHDV-like virus. The proportion of seropositive animals fell when annual rainfall was below 600 mm and rose when it was above 700 mm. Presumably, in areas where rainfall is usually low the proportion of the population infected with the putative RHDV-like virus would slowly drop to a low level, providing a possible basis for the different epidemiological patterns found for RHDV in different parts of Australia.

Multiple warren use by subadult wild rabbits, Oryctolagus cuniculus, and its implications for disease transmission

2017 ◽  
Vol 44 (7) ◽  
pp. 582 ◽  
Author(s):  
Scott Jennings ◽  
Gregory Mutze
Keyword(s):  
Population Density ◽  
Breeding Season ◽  
Disease Transmission ◽  
Critical Role ◽  
Late Summer ◽  
Adult Size ◽  
Contact Rates ◽  
Rabbit Haemorrhagic Disease ◽  
European Rabbits ◽  
Haemorrhagic Disease

Context Contact rates are a key determinant of disease transmission. Territorial behaviour has generally been considered to limit contact between European rabbits occupying different warrens, particularly during the breeding season. Aims We investigated warren use by subadult rabbits during a period of low population density to determine their potential role in transmission of rabbit haemorrhagic disease and myxomatosis. Methods Subadult rabbits were radio-collared in late summer and relocated twice-weekly for 25 weeks, during which time they grew to adult size and breeding commenced. Key results Rabbits of both sexes used an average of four warrens each on a regular basis, even after older rabbits had commenced breeding. Warrens used by individual rabbits formed a continuously overlapping, irregular array. Subadult rabbits did not belong to separate social groups that utilised separate groups of warrens. Conclusions Subadult or young adult rabbits did not display the same territorial warren fidelity that had been previously described for rabbits. They have potential to carry pathogens between warrens at a landscape scale. Implications Movement of subadult rabbits between warrens is therefore likely to play a critical role in disease transmission, particularly when population density is low. This may help to explain the prevalent seasonality of RHD epizootics in spring when first-born litters of each breeding season typically reach that size.

Factors affecting production of inoculum of the blackleg fungus (Leptosphaeria maculans) in south-eastern Australia

2003 ◽  
Vol 43 (10) ◽  
pp. 1231 ◽  
Author(s):  
S. J. Marcroft ◽  
S. J. Sprague ◽  
S. J. Pymer ◽  
P. A. Salisbury ◽  
B. J. Howlett
Keyword(s):  
Management Strategy ◽  
Leptosphaeria Maculans ◽  
Soil Surface ◽  
Factors Affecting ◽  
High Rainfall ◽  
South Eastern ◽  
Eastern Australia ◽  
Blackleg Fungus ◽  
South Eastern Australia

The production of windborne ascospore inoculum of the blackleg fungus (Leptosphaeria maculans) was determined during 2000 and 2001 in 3 environments (Birchip, low rainfall; Wonwondah, medium rainfall; Lake Bolac, high rainfall) in Victoria. The weight of canola stubble (kg/ha) remaining on the soil surface in paddocks was estimated 6, 18, 30 and 42 months after harvest of the original canola crop. In all 3 environments only small amounts of stubble were present 18 months after harvest. Eighty percent of the 6-month-old stubble comprised stems and branches, with the remaining 20% being root material, while 42-month-old stubble consisted only of root material. Paddocks subjected to raking and burning contained only half the weight of stubble compared with paddocks that were harrowed. Where canola was harvested in January, even when no management strategy was used, 80% of subsequent stubble was no longer on the soil surface by July of that year. Pseudothecia from 6-month-old stubble from the high rainfall environment discharged significantly more ascospores than stubble of the same age from the medium rainfall environment, which in turn discharged more than stubble from the low rainfall environment. In all environments, paddocks containing 6-month-old canola stubble discharged 30-fold as many ascospores per hectare as older stubble paddocks.

Breeding of the Stubble Quail, Coturnix pectoralis, in South-Eastern Australia

1980 ◽  
Vol 7 (1) ◽  
pp. 117
Author(s):  
HJ Frith ◽  
SM Carpenter
Keyword(s):  
Breeding Season ◽  
Late Summer ◽  
Early Summer ◽  
Hunting Season ◽  
Annual Cycles ◽  
South Eastern ◽  
Eastern Australia ◽  
Gonad Size ◽  
The One ◽  
Latitudinal Trend

The gonad cycle, breeding season, proportion of the population in primary moult and the relative amount of body fat were examined through the year in stubble quail at eight localities covering seven degrees of latitude and including several types of habitat and climate. There were significant effects of annual cycles and rainfall on each character at each location. In gonad size the seasonal cycle accounted for 39-71% of the variability in males and 21-41% in females according to locality. Effects of rainfall accounted for 5-18 % of the variability in males and 5-19% in females. There was a suggestion of a latitudinal trend in the date of the beginning of the annual gonad cycle. Breeding at all localities was in spring and early summer with a very frequent second peak of gonad size and breeding in late summer and autumn. The timing, the relative values of the spring and summer peaks and the success of the breeding varied from place to place and from year to year in the one locality. In some years breeding was continuous virtually throughout the year. Although in some regions the hunting season is appropriately timed, considering the biology of the birds, in others it is not as it overlaps the breeding season. There is a case for standardization in the south-eastern States to May-July.

Trends in grain production and yield gaps in the high-rainfall zone of southern Australia

2016 ◽  
Vol 67 (9) ◽  
pp. 921 ◽  
Author(s):  
Michael Robertson ◽  
John Kirkegaard ◽  
Allan Peake ◽  
Zoe Creelman ◽  
Lindsay Bell ◽  
...  
Keyword(s):  
Western Australia ◽  
Crop Production ◽  
Crop Yields ◽  
Growing Season ◽  
Yield Potential ◽  
Annual Rainfall ◽  
Potential Yield ◽  
High Rainfall ◽  
Eastern Australia

The high-rainfall zone (HRZ) of southern Australia is the arable areas where annual rainfall is between 450 and 800 mm in Western Australia and between 500 and 900 mm in south-eastern Australia, resulting in a growing-season length of 7–10 months. In the last decade, there has been a growing recognition of the potential to increase crop production in the HRZ. We combined (1) a survey of 15 agricultural consultants, each of whom have ~40–50 farmer clients across the HRZ, (2) 28 farm records of crop yields and area for 2000–2010, (3) 86 wheat and 54 canola yield observations from well managed experiments, and (4) long-term simulated crop yields at 13 HRZ locations, to investigate recent trends in crop production, quantify the gap between potential and actual crop yields, and consider the factors thought to limit on-farm crop yields in the HRZ. We found in the past 10 years a trend towards more cropping, particularly in WA, an increased use of canola, and advances in the adaptation of germplasm to HRZ environments using winter and longer-season spring types. Consultants and the farm survey data confirmed that the rate of future expansion of cropping in the HRZ will slow, especially when compared with the rapid changes seen in the 1990s. In Victoria, New South Wales and South Australia the long-term water-limited potential yield in HRZ areas, as measured by experimental yields, consultant estimates and simulations for slow developing spring cultivars of wheat and canola was 5–6 and 2–3 t/ha for a decile 5 season. For Western Australia it was 4–5 and 2–3 t/ha, where yields were less responsive to good seasons than in the other states. The top performing farmers were achieving close to the water-limited potential yield. There are yield advantages of ~2 t/ha for ‘winter’ over ‘spring’ types of both wheat and canola, and there is scope for better adapted germplasm to further raise potential yield in the HRZ. Consultants stated that there is scope for large gains in yield and productivity by encouraging the below-average cropping farmers to adopt the practices and behaviours of the above-average farmers. The scope for improvement between the below- and above-average farmers was 1–3 t/ha for wheat and 0.5–1.5 t/ha for canola in a decile 5 season. They also stated that a lack of up-to-date infrastructure (e.g. farm grain storage) and services is constraining the industry’s ability to adopt new technology. Priorities for future research, development and extension among consultants included: overcoming yield constraints where growing-season rainfall exceeds 350 mm; adaptation of winter and long-season spring types of cereals and canola and management of inputs required to express their superior yield potential; and overcoming barriers to improved planning and timeliness for crop operations and adoption of technology.

Factors affecting the adoption of productive pastures by participants in a paired-paddock extension program

2000 ◽  
Vol 40 (8) ◽  
pp. 1089 ◽  
Author(s):  
J. P. Trompf ◽  
P. W. G. Sale ◽  
B. Graetz
Keyword(s):  
Regression Models ◽  
Management Practices ◽  
Annual Rainfall ◽  
Stocking Rate ◽  
Factors Affecting ◽  
Exit Survey ◽  
Eastern Australia ◽  
Phosphorus Fertiliser ◽  
Fertiliser Use ◽  
Extension Program

A survey of 146 pastoral producers across south-eastern Australia was conducted after they had participated for 3 years in the Grassland’s Productivity Program. The exit survey, together with earlier surveys, enabled the changes in whole-farm stocking rate and phosphorus fertiliser use, management practices, and perceptions of the Grassland’s Productivity Program, to be determined. The magnitude of the increases in productivity settings and the increased use of most recommended management practices were not influenced by either the facilitator who guided the groups of participants, or by the annual rainfall for the farm, which varied between 400 and 1000 mm. Path analysis of the survey data found that changes in productivity settings during 1993–97 did not depend on any one feature of the extension program. Rather the changes resulted from a hierarchy of interacting effects including certain initial (1993) and final (1997) management practices, attitudes to the program and perceived benefits from the program, and situational constraints such as the availability of suitable soil types on the farm. There were differences in the significant terms in the regression models that predicted the change in stocking rate, the change in fertiliser rate, or the combined variable for both, that was designated as the change index.

Recovery of South Australian rabbit populations from the impact of rabbit haemorrhagic disease

2014 ◽  
Vol 41 (7) ◽  
pp. 552 ◽  
Author(s):  
G. Mutze ◽  
P. Bird ◽  
S. Jennings ◽  
D. Peacock ◽  
N. de Preu ◽  
...  
Keyword(s):  
Late Summer ◽  
Annual Rainfall ◽  
Wild Rabbit ◽  
Contributing Factors ◽  
Rabbit Haemorrhagic Disease ◽  
Transect Counts ◽  
Alternative Hypotheses ◽  
Serological Data ◽  
Haemorrhagic Disease ◽  
The Impact

Context Recovery of Australian rabbit populations from the impact of rabbit haemorrhagic disease virus (RHDV) contrasts with more prolonged suppression of wild rabbits in Europe, and has been widely discussed in the scientific community, but not yet documented in formal scientific literature. The underlying causes of recovery remain unclear, but resistance to RHDV infection has been reported in laboratory studies of wild-caught rabbits. Aims We document numerical changes in two South Australian wild rabbit populations that were initially suppressed by RHDV, and examine serological data to evaluate several alternative hypotheses for the cause of recovery. Methods Rabbit numbers were assessed from spotlight transect counts and dung mass transects between 1991 and 2011, and age and RHDV antibody sero-prevalence were estimated from rabbits shot in late summer. Key results Rabbit numbers were heavily suppressed by RHDV between 1995 and 2002, then increased 5- to 10-fold between 2003 and 2010. During the period of increase, annual RHDV infection rates remained stable or increased slightly, average age of rabbits remained stable and annual rainfall was below average. Conclusions Rabbit populations recovered but neither avoidance of RHDV infection, gradual accumulation of long-lived RHD-immune rabbits, nor high pasture productivity were contributing factors. This leaves increased annual survival from RHDV infection as the most likely cause of recovery. Implications Previously documented evidence of resistance to RHDV infection may be of little consequence to post-RHD recovery in rabbit numbers, unless the factors that influence the probability of infection also shape the course of infection and affect survival of infected rabbits.

Increasing wheat yields in a high rainfall area of Western Australia

1990 ◽  
Vol 30 (5) ◽  
pp. 607 ◽  
Author(s):  
WK Anderson ◽  
WR Smith
Keyword(s):  
Western Australia ◽  
Quality Parameters ◽  
Annual Rainfall ◽  
Seed Rate ◽  
Wheat Production ◽  
High Rainfall ◽  
Agronomic Practices ◽  
Average Annual Rainfall ◽  
N Rates ◽  
High Rainfall Area

Average commercial wheat yields in the southern, high rainfall area of Western Australia have seldom exceeded 1.5 t/ha and wheat is not widely grown. However, the average annual rainfall and length of growing season (>400 mm and >6 months) are conducive to much larger yields. Thirteen factorial experiments with mid and long season cultivars (Aroona and Osprey), 2 levels of applied nitrogen (N) (40 and 80 kg N/ha), 2 seed rates (50 and 100 kg/ha) and with or without fungicide were conducted at 8 sites over 2 seasons. The experiment was done to investigate combinations of cultivar and agronomic practices suitable for increased wheat production in long season environments in Western Australia. Largest grain yields (>4 t/ha) were obtained where wheat followed a grass-free break crop, and the mid season cultivar was used with 80 kg N/ha and 100 kg/ha of seed. Increases due to cultivar and seed rate were more consistent than those due to N, and increases from application of fungicide were less consistent. It is suggested that the optimal wheat production 'package' will include sowing in May in rotation with a grass-free break crop, seed rate of about 100 kg/ha and, when all other factors are optimal, N rates of over 40 kg/ha. The greatest yield increases were associated with the sites where wheat followed a grass-free crop. Increases due to other factors were relatively smaller. Hectolitre weight and percentage of small grain (<2 mm) often reached levels that would have entailed downgrading in commercial deliveries. However, in the most productive crops where root and leaf diseases were minimal, these quality parameters were seldom deficient and grain protein contents exceeded 10% at yields of up to 4 t/ha.

The ecology of the European rabbit (Oryctolagus cuniculus) in coastal southern Western Australia

1998 ◽  
Vol 25 (2) ◽  
pp. 97 ◽  
Author(s):  
Laurie E. Twigg ◽  
Tim J. Lowe ◽  
Gary R. Martin ◽  
Amanda G. Wheeler ◽  
Garry S. Gray ◽  
...  
Keyword(s):  
Breeding Season ◽  
Adult Female ◽  
Western Australia ◽  
Oryctolagus Cuniculus ◽  
European Rabbit ◽  
Demographic Changes ◽  
High Rainfall ◽  
Nonbreeding Season ◽  
Exponential Rates ◽  
Free Ranging

Demographic changes in three free-ranging rabbit (Oryctolagus cuniculus) populations were monitored over 4 years in southern Western Australia. Peak densities followed periods of high rainfall and pasture biomass. The breeding season was prolonged, often extending from at least April to November, with some pregnancies occurring outside this period. Fecundity, determined by the autopsy of pregnant offsite rabbits and the known length of each breeding season, appeared to be relatively high, with the potential for 34–39 kittens doe-1 year-1; however, because not all females are pregnant in all months, the overall productivity of these populations was estimated at 25–30 kittens adult female-1 year-1. Exponential rates of increase varied from 0.13 to 0.30 during the breeding periods and –0.05 to –0.14 during the nonbreeding season. Kitten survival was generally low whereas some adults lived for more than 5 years. Two patterns of myxomatosis were observed: annual epizootics of the disease (3 of 4 years) and an epidemic that slowly spread over many months. European rabbit fleas were most abundant during winter–spring and attained highest densities on adult female rabbits.

The sensitivity of Australian animals to 1080 poison. I. Intraspecific variation and factors affecting acute toxicity

1981 ◽  
Vol 8 (2) ◽  
pp. 369 ◽  
Author(s):  
J. C. Mcilroy
Keyword(s):  
Acute Toxicity ◽  
Intraspecific Variation ◽  
Factors Affecting ◽  
Eastern Australia ◽  
Vertebrate Pests ◽  
Breeding Condition ◽  
Different Populations ◽  
Males And Females

The calculated sensitivity (LD50) of a species to 1080 poison (sodium fluoroacetate), used for control of vertebrate pests, is affected by the experimental procedures employed. Variation can be minimized if the most obvious sources are avoided, as described in this paper. Very young mammals and female waterfowl in breeding condition may be more sensitive to 1080 than other members of their populations. No other substantial differences in sensitivity were found between males and females, immatures and adults, or within and between different populations of six species of birds and mammals in eastern Australia.

Sea-ice and density-dependent factors affecting foraging habitat and behaviour of Adélie penguins throughout the breeding season

2021 ◽  
Vol 168 (7) ◽  
Author(s):  
Nobuo Kokubun ◽  
Louise Emmerson ◽  
Julie McInnes ◽  
Barbara Wienecke ◽  
Colin Southwell
Keyword(s):  
Sea Ice ◽  
Breeding Season ◽  
Foraging Habitat ◽  
Factors Affecting ◽  
Density Dependent ◽  
Adélie Penguins
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