Southern Tasmania Research Articles

Breeding site characteristics regulating life history traits of the brown tree frog, Litoria ewingii

Past research has determined the habitat requirements of amphibian species predominantly from presence/absence studies. This study tested the hypothesis that relationships between breeding site habitat components, life history traits and fitness may provide a higher resolution of biological data relating to the habitat requirements of amphibian species. We tested this novel approach by using Litoria ewingii as our model species. We correlated larval and metamorph life history traits with habitat variables at 28 small to medium sized ponds within a commercially logged forest in southern Tasmania, Australia. To avoid larval mortality due to pond desiccation, L. ewingii laid eggs and metamorphosed earlier in smaller ponds. Snout vent length at metamorphosis increased with elevation and metamorphosis was earlier in less shaded ponds. Breeding ponds that maximised the fitness of L. ewingii were higher elevation ponds with reduced shading, steeper bank slopes and reduced pond isolation. The findings of the study equip land managers with a greater ecological understanding of ecosystem function in relation to specific species. The methodological approach has broad application to conservation biology where an awareness of the specific habitat requirements of amphibians is critical to successful ecosystem management.

Oral cancer at a Tasmanian tertiary referral clinic, The Royal Hobart Hospital 1996–2002

The Holman Clinic at the Royal Hobart Hospital includes a multi-disciplinary head and neck clinic which functions as a tertiary referral centre for Southern Tasmania and involves Ear Nose and Throat surgeons, Oral and Maxillofacial Surgeons, Plastic and Reconstructive Surgeons, Radiation Oncologists and Medical Oncologists. The aim of this study was to examine retrospectively the number, gender distribution, age, site of lesion, histology, mortality and treatment modalities of the oral cancers referred to the Holman clinic at the Royal Hobart Hospital. The medical histories and a database of the Holman clinic were used as the sources of data for this study. A total of 101 patients were treated for oral cancer in the Holman clinic at the Royal Hobart Hospital from 1996 to 2002. There were 64 males and 37 females. The distribution of anatomical sites of the oral cancers in this study was as follows: 36 oral tongue lesions, 17 floor of mouth, 13 lip, five retromolar trigone, five mandibular alveolus, six buccal mucosa, nine palatal and 10 minor and major salivary gland cancers. The most common site of oral cancer was the tongue (35.6 per cent), followed by the floor of mouth (16.8 per cent) and lip (12.9 per cent). The majority of oral cancers were squamous cell carcinoma, except for the salivary gland cancers. The incidence of squamous cell carcinoma was between 67 and 100 per cent, depending upon the site involved. The trends found in this study are similar to those previously documented over the past 20 years.

A new endemic species of Hibbertia (Dilleniaceae) from Tasmania

Hibbertia basaltica A.M.Buchanan & R.B.Schahinger from southern Tasmania is newly described and illustrated, and its habitat and conservation status discussed.

Seasonal activity patterns of the frog, Crinia signifera (Anura: Myobatrachidae), in southern Tasmania, Australia

We investigated the seasonal adaptations of the myobatrachid frog Girard, 1863 in a commercial forest in sourhernTasmania, Australia. Seasonal variation in activity patterns, body size and body condition was investigated. Although C does not hibernate over winter, activity levels arc much reduced during this time. Females trapped in summer were smaller than those captured throughout the remainder of the year. We interpreted seasonal variation in the condition of captured frogs as an indication that breeding in spring and early summer is metabolically costly and fat stores are replenished by extensive foraging in summer. Fat stores accumulated in summer and autumn by males are llsed for body maintenance over winter and breeding in the following spring.

The impact of recent logging and pond isolation on pond colonization by the frog Crinia signifera

A colonization experiment was used to investigate landscape use of a commercially managed wet forest in southern Tasmania by the ground-dwelling frog, Crinia signifera. Replicated artificial ponds were placed at increasing distances (20, 100, 250 and 500 m) from nine permanent breeding sites to investigate the effect of pond isolation on colonization. Four of these permanent breeding sites were surrounded by coupes that had been logged within the previous five years and five permanent breeding sites were surrounded by unlogged forest to investigate the effect of recent logging on colonization. The rate of colonization, the frequency of colonization, male size and female size (inferred from clutch size) were monitored over two breeding seasons. No pond isolation effects were found, indicating that G. signifera is randomly distributed throughout the forest landscape for up to 500 m around each permanent breeding site. Such patterns of forest habitat use indicate that management prescriptions should not only take into account the habitat characteristics of breeding sites but should also consider the surrounding terrestrial landscape. Ponds surrounded by unlogged forest were colonized almost two times faster than ponds surrounded by logged forest indicatlng that landscape modtfication can significantly alter amphibian mobility. These findings have consequences for total reproductive output especially in landscapes where breeding sites are highly variable and for species that are slow to colonize new breeding sites.

Survey for viruses in oilseed poppy in Tasmania, Australia

Oilseed poppy (Papaver somniferum) crops in Tasmania were surveyed for beet western yellows virus, tomato spotted wilt virus, and for potyviruses and carlaviruses. Twenty-seven crops encompassing all areas of poppy production were systematically sampled over two years and none of these viruses were detected. However, before this survey, a potyvirus was detected in a single plant in the Coal River Valley in southern Tasmania. Infection was confirmed by serological testing and electron microscopy.

An aeolian sediment pulse at c. 28 kyr BP in southern Tasmania

Thick aeolian deposits are uncommon in Tasmania but a 7‐m‐thick aeolian deposit containing two stratigraphic breaks, including one palaeosol, occurs as a gully infill at Cradoc Hill, 5 km east of the lower Huon River floodplain in southern Tasmania. The deposit was sampled at six depths for dating by thermoluminescence (TL) techniques. The entire deposit gave TL ages in the range 25–32 kyr BP (mean 28 kyr BP). One date of 41.4 kyr BP was discounted as being probably erroneous. In contrast to loess deposits of similar thickness in New Zealand, which have been dated and correlated with entire glacial periods, the Cradoc Hill aeolian sediments are interpreted to have been deposited in two stages over a relatively short time. As the prevailing winds in the region are westerly, the aeolian material is presumed to be derived from the Huon River floodplain in the vicinity of Egg Island, when the floodplain was occupied by a braided river; some of the sand component may also have been derived from locally outcropping sandstone rocks. Aeolian sediments of this age have not previously been recognised in Tasmania. A significant climate event that might explain a short and intense period of river aggradation and aeolian sediment supply has not been noted in either the pollen or δ18O record. An alternative explanation for the erosion and subsequent aeolian deposition is that it resulted from natural or human‐lit fires. Aboriginal settlement of Tasmania began around 35 kyr BP and the earliest recorded human settlement in the Huon catchment occurred at 28–29 kyr BP. A major erosion event in the mid‐Huon Valley also occurred at about this time (27–29 kyr BP). Thus, Aboriginal settlement in the Huon catchment, erosion in the mid‐Huon Valley, and deposition at Cradoc Hill are approximately contemporaneous. As older aeolian deposits are not present at Cradoc Hill, it is suggested that Aboriginal burning of vegetation rather than climatic influences may have caused both the middle Huon erosion event and aggradation downstream at about 28 kyr BP, providing a source of silt and fine sand which accumulated downwind, together with sand from local sources, as gully‐infill sediments. We therefore suggest that as Aboriginal people reached southern inland Tasmania they may have had an influence on landscape stability, river morphology, and aeolian dust supply. This suggestion requires corroboration from other sites.

SHRIMP U–Pb detrital zircon ages from Proterozoic and Early Palaeozoic sandstones and their bearing on the early geological evolution of Tasmania

Detrital zircons from 13 Late Mesoproterozoic to Early Neoproterozoic sandstones and two Palaeozoic sandstones from Tasmania were dated in order to improve constraints on depositional ages, to test correlation between Proterozoic inliers, and to characterise source regions. These include successions considered to be the oldest presently exposed in Tasmania. Typical features of the age distributions of the Proterozoic rocks are prominent data concentrations at 1800–1650 Ma and 1450–1400 Ma, and a minor spread of Archaean ages. Statistical testing of the similarity of the age profiles shows that widespread quartzarenaceous samples from the Detention Subgroup, Needles Quartzite and from the Tyennan region are strongly similar, consistent with broad correlation. Relatively large differences are seen between the Detention Subgroup and the conformable, stratigraphically higher Jacob Quartzite, which contains an additional spread of 1300–1000 Ma zircons suggestive of a Grenvillian source. Age profiles of the quartzarenites and quartzwacke turbidites (Oonah Formation and correlatives) cannot be readily differentiated. The Oonah Formation likewise includes samples with and without Grenvillian ages, and there is no 750 Ma zircon population that would be expected if the turbidites were genetically related to the Wickham Orogeny. The simplest interpretation is that the quartzarenites (Rocky Cape Group and correlatives) and the turbidites (Oonah Formation and correlates) are lateral equivalents, although a younger (post-Wickham Orogeny) age for the Oonah Formation cannot be discounted. A maximum age of ca 1000 Ma is inferred for the Oonah Formation, Rocky Cape Group and correlatives. A minimum age of ca 750 Ma is provided by the basal age of the overlying Togari Group and correlatives. In a metasediment from western King Island, the youngest detrital zircons are ca 1350 Ma, allowing a pre-Grenvillian depositional age as suggested by previous dating of metamorphic monazite. However, the age profile of this sample is not dissimilar to the other Tasmanian successions that are inferred to be 1000–750 Ma. The Wings Sandstone, of southern Tasmania, contains an unusual profile dominated by Grenvillian ages, consistent with an allochthonous origin. Basement ages that broadly match the age spectra of the Tasmanian Proterozoic sediments are found in southwestern Laurentia, consistent with mutual proximity in Rodinia reconstructions. The Palaeozoic sandstones, from the turbiditic Mathinna Supergroup of northeastern Tasmania, have zircon age profiles typical of the Lachlan Fold Belt, with a predominant latest Neoproterozoic-Early Cambrian component and a lesser, broad Proterozoic data concentration at ca 1000 Ma. Western Tasmania was not a significant part of the source area for these rocks.

A community-based educational intervention to improve antithrombotic drug use in atrial fibrillation.

Despite evidence that antithrombotics are effective in reducing the risk of stroke in atrial fibrillation (AF), they remain underused. To perform a controlled trial of a comprehensive educational program promoting the rational prescribing of antithrombotics for stroke prevention in AF. The intervention was conducted in Southern Tasmania, Australia, using Northern Tasmania as a control area. General practitioners were sent locally produced guidelines on stroke risk stratification and antithrombotic drug use in AF, which were followed by academic detailing visits. Outcomes were measured using evaluation feedback from the general practitioners, and drug utilization data were provided by a series of patients presenting to the hospital with an admission diagnosis of AF and dispensing of antithrombotic therapy under the Australian Pharmaceutical Benefits Scheme. During the educational intervention, 272 guidelines were mailed and, subsequently, 162 general practitioners were visited and the guidelines discussed. Hospital admission data before and after the intervention revealed a significant increase in the use of warfarin in patients at high risk of stroke (33% vs 46% of eligible patients; p < 0.05). Analysis of prescription data for warfarin also indicated that the increase in use of warfarin within the intervention region was significantly greater than for the control region (p < 0.001). The educational program described here led to a significant increase in the prescribing of warfarin for stroke prevention in patients with AF.

Vitamin D insufficiency in adolescent males in Southern Tasmania: prevalence, determinants, and relationship to bone turnover markers.

There are limited data on vitamin D insufficiency in healthy children. The aim of this study was to describe the prevalence and determinants of vitamin D insufficiency and its association with bone turnover in adolescent boys (N = 136, mean age 16 years). Sun exposure and physical activity were assessed by questionnaire. Vitamin D stores were assessed by serum 25-hydroxyvitamin D3 (25[OH]D3). Bone turnover was assessed by bone-specific alkaline phosphatase (BAP) and urinary pyridinoline (PYR) to creatinine (Cr) ratio (mmol PYR/micromol Cr). The mean 25(OH)D3 level was low (44 nmol/l; 68% < 50 nmol/l; range, 16-87) and was associated with self-reported sun exposure on winter weekends (r = 0.23, p = 0.01), school holidays (r = 0.22, p = 0.01), and weekdays (r = 0.17, p = 0.05). It was also associated with number of sports (r = 0.34, p < 0.001) and vigorous activity (r = 0.22, p = 0.01) but not television, computer, and video watching (r = -0.04, p = 0.68). In multivariate analysis, number of sports but not total sun exposure remained significantly associated with 25(OH)D3. Furthermore, 25(OH)D3 was significantly associated with BAP in cutpoint analysis (cutpoint 55 nmol/l, p = 0.03) but not continuous analysis (r = -0.12, p = 0.16) and PYR in both forms (r = -0.23, p = 0.01, cutpoint 43 nmol/l, p = 0.01). In conclusion, vitamin D insufficiency is common in healthy adolescent boys in winter in our setting, is primarily derived from sports-related sun exposure, and is associated with bone turnover markers. These data suggest that a 25(OH)D3 level of at least 43-55 nmol/l is required for optimal bone health in children.

Karenia asterichroma sp. nov. (Gymnodiniales, Dinophyceae), a new dinoflagellate species associated with finfish aquaculture mortalities in Tasmania, Australia

A new species of unarmoured dinoflagellate is described from Tasmanian field samples and laboratory cultures: Karenia asterichroma de Salas, Bolch & Hallegraeff, sp. nov. This species is characterized by the use of light and scanning electron microscopy and sequencing of the 26S ribosomal RNA gene. Karenia asterichroma is a dorsoventrally flattened cell resembling K. brevis, although it differs from this species by 4.5% in the D1–D3 regions of its 26S ribosomal DNA (rDNA) sequence. Unlike other Karenia species, the epicone of K. asterichroma has concave sides and the chloroplasts radiate from a central, putative pyrenoid. The nucleus is located in the centre of the epicone and the apical groove is long, extending ventrally to near a broad sulcal extension into the epicone. Partial 26S rDNA sequences indicate a relationship with K. bicuneiformis. Although the ichthyotoxicity of K. asterichroma is yet to be confirmed, it was associated (with three other Karenia species) with a recent mass mortality of over 100,000 caged salmonids at an aquaculture operation in southern Tasmania, Australia.

Anthesis, pollination and fruitset in Pinot Noir

Aspects of pollination and resulting fruitset in Vitis vinifera cv. Pinot Noir were investigated in a cool climate wine area of Southern Tasmania (Australia). Changes in the appearance of the stigmatic surface and pollen grains were recorded using environmental scanning electron microscopy (ESEM). Flowers with the calyptra intact (before capfall), showed an apparently turgid stigmatic surface and pollen grains present on the surface were slender and elongated (L/D 35 μm/15 μm). Stigmas had a more flaccid appearance after capfall and pollen grains were more spherical and less elongated in shape (L/D 28 μm/20 μm). Pollen was visible on the stigma surface before capfall, indicating that anthesis occurred whilst the calyptra was in place. Pollen viability tests showed that the pollen was already viable at this stage, and it remained viable until after the flower had been open for several days. Fluorescence micrographs showed no evidence of pollen tube growth until after capfall. Flowers covered by waxed paper bags to eliminate external pollen and thus allow only self-pollination, gave a percentage fruitset equal to that of flowers where external pollen was not excluded. Results indicate that Pinot Noir can be self-pollinated, and that while anthesis commences prior to capfall, fertilisation does not proceed until after capfall.

Analysis of sampling methods for coarse woody debris

Coarse woody debris (CWD) is an important structural component of forest ecosystems and plays a key role in ecosystem functioning. It includes whole fallen trees and branches, pieces of fragmented wood, stumps, and standing dead trees (snags). A number of sampling approaches have been used to quantify CWD but there has been little systematic analysis of alternative approaches in terms of sampling efficiency. This study analysed sampling methods for CWD in three Australian forest types: eucalypt-dominated woodlands in south central Queensland, eucalypt open forest (dry sclerophyll forest) in south coastal New South Wales and eucalypt tall open forest in southern Tasmania. All downed wood (greater than 10 cm in woodland and 15 cm in other forest types) was measured and mapped on several large plots (1 ha) at each site. Alternative sampling approaches were compared using a computer-based system. These included varying length and arrangement of lines for the line intersect method and varying sizes of fixed-area plots. Variability of CWD volume in forests is relatively high and achieving estimates with a precision (coefficient of variation) less than 50% of the mean requires a high sampling intensity. In analysis of the line intersect method, precision of volume estimates increased as total transect length increased. In denser forests, transects of at least 100 m are required to achieve a precision of less than 100% of the mean. A single long transect resulted in lower coefficient of variation than a number of short transects and is generally more cost effective. There was no improvement in precision by arranging the total transect length in an ‘L’ shape, a triangle or a square. In woodland vegetation (20–50% canopy cover) the amount of CWD is relatively low and variability is high. In these situations fixed-area plots are preferred. 20 m×20 m plots give estimates with a mean coefficient of variation less than 100% in the more dense forest structures but well over 100% in woodlands. Measuring all pieces on a 50 m×50 m plot in woodlands gave estimates with a precision of ±21–73% of the mean.

Genetic variation of Eucalyptus globulus in relation to autumn gum moth Mnesampela privata (Lepidoptera: Geometridae) oviposition preference

The autumn gum moth Mnesampela privata Guenée is a major defoliator of Australia’s commercially important pulpwood plantation species, Eucalyptus globulus Labill. However, little is known about genetic variability of E. globulus to M. privata oviposition preference. We examined oviposition preference by exposing juvenile foliage sprigs of different genetic origins to gravid female moths in cage bioassays. Foliage sprigs were collected from 40 E. globulus families grown in a common environment field trial in southern Tasmania. These families were derived from open-pollinated seed collected in native stands and represented four geographic races of E. globulus. Significant differences in the level of oviposition was detected between foliage sprigs from the different races, with those from the Furneaux race receiving over twice as many egg batches compared to those from either the Strzelecki Ranges or northeastern Tasmania races. The southern Tasmania race received an intermediate egg load. No significant variability in oviposition preference was identified between different localities within races or between different open-pollinated families within localities. Selections from both the Strzelecki Ranges and Furneaux races comprise a large component of the Australian E. globulus breeding population. There is therefore likely to be significant genetic variation for M. privata oviposition preference within the breeding population and by screening before deployment gains in plantation productivity in areas subject to M. privata outbreaks may be possible.

Genetic variation of Eucalyptus globulus in relation to autumn gum moth Mnesampela privata (Lepidoptera: Geometridae) oviposition preference

The autumn gum moth Mnesampela privata Guenée is a major defoliator of Australia’s commercially important pulpwood plantation species, Eucalyptus globulus Labill. However, little is known about genetic variability of E. globulus to M. privata oviposition preference. We examined oviposition preference by exposing juvenile foliage sprigs of different genetic origins to gravid female moths in cage bioassays. Foliage sprigs were collected from 40 E. globulus families grown in a common environment field trial in southern Tasmania. These families were derived from open-pollinated seed collected in native stands and represented four geographic races of E. globulus. Significant differences in the level of oviposition was detected between foliage sprigs from the different races, with those from the Furneaux race receiving over twice as many egg batches compared to those from either the Strzelecki Ranges or northeastern Tasmania races. The southern Tasmania race received an intermediate egg load. No significant variability in oviposition preference was identified between different localities within races or between different open-pollinated families within localities. Selections from both the Strzelecki Ranges and Furneaux races comprise a large component of the Australian E. globulus breeding population. There is therefore likely to be significant genetic variation for M. privata oviposition preference within the breeding population and by screening before deployment gains in plantation productivity in areas subject to M. privata outbreaks may be possible.

Miocene volcanic seamounts on northern Lord Howe Rise: Lithology, age and origin

Multibeam sonar swath‐mapping has revealed small submarine volcanic cones on the northeastern Lord Howe Rise, a submerged ribbon continent. Two such cones, aligned north‐northwest and 120 km apart, were dredged at 23–24°S. Water depth is about 1150 m nearby: the southern cone rises to 750 m and the northern to 900 m. Volcanic rocks dredged from the cones are predominantly highly altered hyalodastites with minor basalt. The clasts are mostly intensely altered vesicular brownish glass with lesser basalt, set in zeolitic, clayey, micritic, or ferruginous cement. Lavas and hyalodastites contain altered phenocrysts of olivine and plagioclase, and fresh clinopyroxene. The latter have compositions between acmite and Ti‐augite, matching clinopyroxene phenocrysts in undersaturated intraplate basanitic mafic lavas. Interbedded micrites in the volcaniclastics represent calcareous ooze that was deposited with (or later than) the volcanic pile. Foraminifers indicate that the micrite is dominantly Early Miocene (ca 16 Ma), and that the ooze was deposited in cool water. Upper Miocene to Pliocene micrites, presumed to be later infillings, all contain warm‐water forms. This evidence strongly suggests that both cones formed in pelagic depths in the Early Miocene. Ferromanganese crusts from the two cones are up to 7 cm thick and similar physically, but different chemically. The average growth rate is 4 mm/106 y. Copper, nickel, and cobalt content are relatively high in the north, but copper does not exceed 0.08 wt%, nickel 0.65%, and cobalt 0.25%. The Mn:Fe ratio is high in the south (average 13.7) suggesting strong hydrothermal influence. Such small volcanic cones related to intraplate hot‐spot‐type volcanism may occur in extensive fields on the Lord Howe Rise, like those off southern Tasmania. On the Lord Howe Rise, the known small volcanic cones coincide with broad gravity highs in areas of shallow continental basement. The highs are aligned parallel to the Lord Howe Rise margins, and it is probable that the Miocene volcanism is related to jostling on older faults. Other fields of small volcanic seamounts may occur on the Lord Howe Rise on such fractured gravity highs.

Evaluation of the use of pre- and post-harvest bulk density measurements in wet Eucalyptus obliqua forest in Southern Tasmania

Abstract Criteria and indicators under the Montreal process are intended to provide a common framework for describing and evaluating progress towards sustainable forest management. In 1998 a nationally coordinated project was initiated to evaluate proposed Montreal indicators 4.1.d and 4.1.e and to provide advice to state agencies on how these indicators could be applied. Interim indicator 4.1.e quantifies ‘ Proportion of harvested forest area with significant change in bulk density of any horizon of the surface (0–30 cm) soil ’. Application and evaluation of this interim indicator was conducted as part of the Warra Silvicultural Systems Trial, in Tasmania, Australia. This forest was composed of wet mixed regrowth/mature Eucalyptus obliqua forest with a dense rainforest understorey. Pre-harvest soil sampling was conducted in four stands followed by post-harvest sampling at two of the sites. Pre-harvest sampling according to soil drainage class, showed that there was a high natural variation in bulk density within individual stands and between neighbouring stands. Post-harvest sampling was stratified according to major operational areas and disturbance classes, including snig tracks (major and minor), firebreaks, harvested and unharvested areas, landings and access roads. Forest harvesting substantially increased the variability of soil bulk density. Though moderate and severe disturbance of the snig tracks and firebreaks increased average soil bulk density, changes in soil bulk density were not uni-directional. Many of the post-harvest samples showed a marked decline in soil bulk density due to the incorporation of litter and slash in the upper soil layer. Bulk density changed most in the upper 0–100 mm layer of soil. Hence there is reasonable argument that monitoring changes in bulk density should be limited to this depth. This would substantially reduce the cost of replicate sampling to the 300 mm depth. The high natural variation found for soil bulk density and the fact that changes are not uni-directional means that it is unlikely that the interim indicator proposed can be implemented in a practical, sensitive and cost-effective manner in the forest type examined in this study.

Ammonium thiosulphate as a blossom thinner of 'Delicious' apple, ' Winter Cole' pear and 'Hunter' apricot

The efficacy of ammonium thiosulphate as a blossom thinner of ‘Delicious’ apple, ‘Winter Cole’ pear and ‘Hunter’ apricot in southern Tasmania was assessed. Ammonium thiosulphate at concentrations of 0.3, 1.5 and 4% (v/v) was applied to both ‘Delicious’ apple and ‘Winter Cole’ pear trees at 20% bloom, 50% bloom or full bloom. At 4%, ammonium thiosulphate proved to be phytotoxic to both crops, resulting in the severe burning of foliage and flowers and also bud death. At 1.5%, ammonium thiosulphate reduced the crop load to an acceptable level without excessive damage. The 0.3% concentration was ineffective regardless of time of application in ‘Delicious’ and at 20% bloom in ‘Winter Cole’. Russet incidence was increased on ‘Delicious’ by the highest concentration applied at 20% bloom. Shoot number increased in some treatments, however there was no effect on return bloom. When ammonium thiosulphate at 2.0% was applied to ‘Hunter’ apricot at 20, 40, 60, 80 or 100% bloom, fruit set was reduced regardless of time of application. Ammonium thiosulphate also improved return bloom of ‘Hunter’ apricot.

Geographic Variation in Oil Characteristics in Melaleuca ericifolia

Variations in the chemical composition and concentration of foliar essential oils of Melaleuca ericifolia from throughout the natural range of the species in southeastern Australia have been studied. The principal aim was to identify seed sources that had abundant oil with relatively high proportions of linalool in combination with relatively low proportions of 1,8-cineole for establishment of pilot plantations. Oil yield (w/w% DW ± SD) was greatest amongst NSW populations (3.2% ± 0.95) and poorest amongst the populations from western Victoria and northwestern Tasmania (0.6% ± 0.3). Oil composition varied quantitatively throughout the species range rather than qualitatively in an apparent association with latitude of occurrence. Linalool and linalool oxide were abundant in the oils from the north of the species range in New South Wales with a gradual southerly decline in these compounds to central Victoria with concomitant increase in the proportions of 1,8-cineole, α-terpineol and limonene. The most southerly populations sampled in southern Victoria and Tasmania gave oils containing relatively high proportions of 1,8-cineole (mean 34.5% ± SD 6.6) and low proportions of linalool (3% ± 4.5). Four populations from the Central Coast of NSW (Coopernook, Hawks Nest, The Entrance and Tuggerah Lake) provided the greatest opportunity of identifying seed trees that combine the attributes required for plantation development. The tree that had the best combination of oil traits (DL 3116 from Hawks Nest) had an oil yield of 4.5%, a linalool content of 60% and a 1,8-cineole content of 16%.

Genetic variation in Eucalyptus globulus in relation to susceptibility from attack by the southern eucalypt leaf beetle, Chrysophtharta agricola

The southern eucalypt leaf beetle, Chrysophtharta agricola (Chapuis), is an outbreak insect pest of commercial Eucalyptus globulus Labill. plantations in south-eastern Australia. We surveyed a young E. globulus family trial in southern Tasmania to determine whether genetic variation existed in the susceptibility of trees to C. agricola field oviposition. The family trial consisted of 225 families, derived from open-pollinated seed collected from native stands at 24 different localities, representing nine geographic subraces. The survey showed that E. globulus subraces from Victoria were significantly more susceptible to C. agricola oviposition than Tasmanian subraces. Significant additive genetic variation within subraces was evident for the number of egg batches, larval clutches and their combination (infestation level), although these heritability scores were all low (egg batches h2op = 0.09; larval clutches h2op = 0.14 and infestation level h2op = 0.11). Subsequent tree defoliation was significantly positively correlated with infestation at a phenotypic, genetic and environmental level. No significant differences in C. agricola oviposition on foliage sprigs was detected among subraces in an ex situ caged oviposition experiment. However, the cage experiment proved to be a good predictor of field oviposition, accounting for 70 and 88% of variation in field oviposition among localities and subraces, respectively.