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Wollongbar, Australia

Micheli-Campbell M.A.,University of Queensland | Gordos M.A.,Wollongbar Agricultural Institute | Campbell H.A.,University of Queensland | Booth D.T.,University of Queensland | Franklin C.E.,University of Queensland
Journal of Zoology | Year: 2012

Incubation temperature influences the phenotype of the hatchling turtles. The aims of the present study were to investigate the daily fluctuations in temperature to which eggs of the freshwater turtle Elusor macrurus are exposed to in the wild and examine how these fluctuations may affect the phenotype and performance of the hatchlings. Eggs in the wild experienced an overall mean daily fluctuation of 5.7°C throughout the incubation period, but on particular days, the variation was as low as 2°C and as high as 22°C. Fifty-four eggs were collected from the wild and incubated in the laboratory at one constant (28°C) and two fluctuating (28 ± 3 and 28 ± 6°C) thermal regimes. Egg mass, incubation length and hatching success (89%) were similar for the 28 and 28 ± 3°C groups, whereas the 28 ± 6°C group only had a 5% hatching success, and the incubation length was 10 days longer. Upon hatching, there was no significant difference in body mass or straight carapace length between the 28 and 28 ± 3°C groups, and within the first 8 weeks of hatching, there was no significant difference in growth rate, self-righting time, crawling speed and swimming performance. A single survivor from the 28 ± 6°C group had a body mass that was 27% less compared with the other two groups and it did considerably poorer in all the performance tests. The study findings illustrated that daily fluctuations in incubation temperature up to 6°C had no effect upon hatchling E.macrurus phenotype, but there was a limit (12°C) by which the extent and recurrence of these fluctuations became detrimental. These thermal regimes are not yet apparent in the wild but will occur within the geographical range of this species according to climate change predictions. © 2012 The Authors. Journal of Zoology © 2012 The Zoological Society of London. Source


Butler G.L.,Grafton Fisheries Center | Rowland S.J.,Grafton Fisheries Center | Baverstock P.R.,Southern Cross University of Australia | Morris S.,Wollongbar Agricultural Institute
Ecology of Freshwater Fish | Year: 2012

Understanding the larval ecology of individual fish species is fundamental in ensuring their long-term conservation. The endangered eastern freshwater cod, Maccullochella ikei, is endemic to the Clarence and Richmond River systems of north-eastern New South Wales, Australia. Little is known about the behaviour of larval M. ikei in the wild, particularly before and after the swim-up stage, and following dispersal from the nest site. The aims of this study were to quantify the swimming ability, depth selection, light preference and substrate selection of hatchling to day-30 M. ikei under controlled laboratory conditions, and to describe its growth and development over the same period. Maccullochella ikei larvae grew constantly but not consistently during the experiment. Exogenous feeding commenced around day 12, prior to the full exhaustion of the yolk. Maximal swimming ability improved daily, but maximum swimming speed declined significantly between days 12 and 13 and remained low. Maccullochella ikei larvae were initially photonegative but were positively phototactic by day 10. Depth selection was for the benthos until day 8, beyond which time larvae dispersed to all depths when released. Substrate selection was for sand in younger larvae but changed to upstream substrates as the experiment progressed. The results of the current study suggest that the period between day 10 and day 20 is critical in the early ontogeny of M. ikei, when it switched phototrophic behaviour, transitioned from endogenous to exogenous feeding and experienced a decline in swimming ability. © 2011 John Wiley & Sons A/S. Source


Dear B.S.,Wagga Wagga Agricultural Institute | Peoples M.B.,CSIRO | Hayes R.C.,CSIRO | Swan A.D.,CSIRO | And 4 more authors.
Crop and Pasture Science | Year: 2010

Changes in pasture yield and botanical composition due to gypsum application were examined on Vertosols at two locations of differing soil sodicity, Grogan and Morangarell, in southern New South Wales. Two pasture treatments were examined. One was an annual pasture comprised of 3 annual legumes (2 subterranean clover Trifolium subterraneum L. cultivars, Clare and Riverina, and balansa clover T. michelianum Savi cv. Paradana), while the second treatment consisted of lucerne (Medicago sativa L.) cv. Aquarius sown in a mixture with the same annual legumes. Gypsum had no effect on the establishment or persistence of lucerne at either site. Gypsum increased the number of subterranean clover seedlings present in autumn in annual swards at the more sodic Grogan site in each of the 4 years, but provided no difference when the clover was in a mixture with lucerne. Annual legume seed yields in annual-only swards increased with gypsum by up to 58% at Grogan and 38% at Morangarell. Seed yields of both cultivars of subterranean clover declined as a proportion of the total annual legume seed bank when lucerne was included in the mixture, in contrast to balansa clover (at Grogan) and the naturalised annual legumes, burr medic (M. polymorpha L.) and woolly clover (T. tomentosum L.), which all increased in relative seed yield in the presence of lucerne. Total pasture production at the Grogan site increased with gypsum by up to 15% per annum in annual swards and 36% in lucerne swards depending on the season. Yield responses to gypsum by the lucerne component were observed in 10 of the 13 seasonal yield measurements taken at Grogan. However, total pasture yield and seasonal yields were unaffected by both gypsum and pasture type at the less sodic Morangarell site. It was concluded that sowing a diverse mixture of annual legumes or polycultures was conducive to maintaining productive pastures on these spatially variable soils. Lucerne dried the soil profile (0.151.15m) more than annual pastures at both sites. The combination of gypsum and lucerne enhanced water extraction at depth (0.61.15m) at the Grogan site increasing the size of the dry soil buffer whereas gypsum increased soil water at depth (0.6m) under annual swards. © CSIRO 2010. Source


Campbell H.A.,University of Queensland | Dwyer R.G.,University of Exeter | Gordos M.,Wollongbar Agricultural Institute | Franklin C.E.,University of Queensland
Proceedings of the Royal Society B: Biological Sciences | Year: 2010

Population decline and a shift in the geographical distribution of some ectothermic animals have been attributed to climatic warming. Here, we show that rises in water temperature of a few degrees, while within the thermal window for locomotor performance, may be detrimental to diving behaviour in air-breathing ectotherms (turtles, crocodilians, marine iguanas, amphibians, snakes and lizards). Submergence times and internal and external body temperature were remotely recorded from freshwater crocodiles (Crocodylus johnstoni) while they free-ranged throughout their natural habitat in summer and winter. During summer, the crocodiles' mean body temperature was 5.2 ± 0.1 ° C higher than in winter and the largest proportion of total dive time was composed of dive durations approximately 15 min less than in winter. Diving beyond 40 min during summer required the crocodiles to exponentially increase the time they spent on the surface after the dive, presumably to clear anaerobic debt. The relationship was not as significant in winter, even though a greater proportion of dives were of a longer duration, suggesting that diving lactate threshold (DLT) was reduced in summer compared with winter. Additional evidence for a reduced DLT in summer was derived from the stronger influence body mass exerted upon dive duration, compared to winter. The results demonstrate that the higher summer body temperature increased oxygen demand during the dive, implying that thermal acclimatization of the diving metabolic rate was inadequate. If the study findings are common among air-breathing diving ectotherms, then long-term warming of the aquatic environment may be detrimental to behavioural function and survivorship. © 2010 The Royal Society. Source


Huwer R.K.,Wollongbar Agricultural Institute | Maddox C.D.A.,Wollongbar Agricultural Institute | Hickey M.,Wollongbar Agricultural Institute | Llewellyn R.,BioResources Pty. Ltd. | And 2 more authors.
Acta Horticulturae | Year: 2015

Fruitspotting bugs (FSB) Amblypelta nitida Stål and Amblypelta lutescens lutescens Distant (Hemiptera: Coreidae) are major native pests in subtropical and tropical horticultural crops in Australia, and key pests in avocado. Until now, using a single targeting approach, namely broad-spectrum insecticides, has been the only management option for growers. However, this approach is not sustainable in the long-term. A single strategy approach from different research teams has also not been able to find a solution, and therefore a multi-target approach is needed. In March 2011, a multi disciplinary collaborative project commenced. Team members included state government agencies from New South Wales and Queensland, the University of Queensland, BioResources Pty. Ltd., and private consultants. Major components of the management strategy under investigation are the following: 1. Chemical control 2. Monitoring and trap cropping a. Trap cropping and monitoring using alternative host and highly susceptible cultivars b. Pheromone traps 3. Biological control a. Investigation of biological control agents (ecology and biology) b. Mass-rearing of FSB and biological control agent 4. Integrated Pest Management (IPM) case studies - demonstrations on commercial farms 5. Area Wide Management (AWM) - management tested and coordinated on an areawide- scale 6. Industry adoption The project has made progress in all different components, and progress results will be presented. Different new management tools will become available at different times with new chemicals most likely to be the first new tool. The project is guided by industries including avocado, macadamia, lychee and papaya, passionfruit, and custard apples, with the avocado and macadamia industries being the major contributors. Source

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