bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of Forest Clumps on Chenier Plains, Cobourg Peninsula, Northern Territory
Authors: Bowman DMJS , Panton WJ , Mcdonough L
Published: December 2005

Forest clumps occur scattered throughout Sorghum plumosum grasslands on chenier plains at Gurig National Park, Cobourg Peninsula, a preferred habitat for the introduced banteng (Bos javanicus.). The clumps are dominated by Pandanus spiralis, Acacia auriculiformis, Alstonia actinophylla, Timonius timon and Casuarina equisetifolia and vary in size from the radius of one tree crown to large patches of over several hectares. Fifteen of the 32 woody species recorded in 42 clumps occurred as juveniles less than 1 cm diameter at breast height. Both the clumps and grasslands occur on uniform calcareous soils. The clumps are thought to be a stage in a succession towards monsoon forest. Field experiments showed that seedlings from a range of monsoon forest and savanna species can grow on the plains. Interpretation of aerial photography taken in 1963 and 1982 suggests that the clumps have expanded. Fire is thought to control the succession. A fire on the plains was found to kill between one and two-thirds of the basal area of Pandanus spiralis and A. auriculiformis and stimulated the establishment of six times more A. auriculiformis seedlings than in nearby unburnt clumps. Monsoon forest juveniles that invade the clumps typically resprout following fire. Stunted, fire-damaged monsoon forest species (e.g. Timonius timon, Alstonia actinophylla) occur in low densities in the grasslands. It is unclear whether banteng promotes the succession by reducing fuel loads in the grasslands and spreading A. auriculiforms seeds.
Polymorphism, Outcrossing and Polyploidy in Bromus diandrus and B. rigidus
Authors: Kon KF , Blacklow WM
Published: December 2005

The genetic systems of Brornus diandrus Roth (great brome) and B. rigidus Roth (rigid brome) were
studied in 30 populations sampled from Western Australia. Populations of B. diandrus were polymorphic and the dominant phenotype had scabrid lemmas and glabrous paleas. Polymorphs of B. rigidus
had short and long awns with flat seeds and long awns with round seeds: all these phenotypes had scabrid
lemmas and hairy paleas. Frequencies of the polymorphs varied between sites and years. Palea hairiness
of B. diandrus is controlled by a single, dominant gene and was used as a marker gene for estimations
of outcrossing frequencies and population homozygosis. B. diandrus is self-compatible and inbreeding
with outcrossing frequencies less than 1%. Florets of both species were facultatively cleistogamous;
there were high levels of chasmogamy in irrigated populations but most anthers had dehisced prior to
exsertion. The high proportion of seed set in cleistogamous florets and similar floral biology suggested
that the breeding system of B. rigidus was similar to that of B. diandrus. There was no evidence of
species hybrids in the field and attempts at hybridisation failed. Populations of these species were
homozygotic for a few major genotypes. Meiotic chromosomes of both species and all biotypes formed
mainly bivalents and a few quadrivalents at metaphase I. This, together with the high proportion
(Ͱ5 98%) of fertile pollen grains and the 3 : 1 segregation of hairy: glabrous paleas in selfed F2
progenies, indicated that inheritance in these species was disomic. The genomic formula proposed for
B. diandrus is either AABBCCDD or AAAABBCC. The properties of polymorphism, autogamy and
disomic inheritance within polyploidy would favour the development of tolerance to herbicides within
populations, provided selected genotypes were competitive.
Heat shock, smoke and darkness: partner cues in promoting seed germination in Epacris tasmanica (Epacridaceae)
Authors: Gilmour Craig A. , Crowden Ronald K. , Koutoulis Anthony
Published: December 2005

The Epacridaceae is one of the families that dominate Australian heathlands,
environments prone to disturbance events such as fire and seasonal drought. To
investigate the role of fire-related cues in breaking seed-dormancy mechanisms
in the Epacridaceae, the influences of heat shock, darkness, direct smoke and
varying concentrations of aqueous smoke solutions (5, 10 and 100%) on
seed germination of the Tasmanian endemic
Epacris tasmanica were examined. A small fraction
(5.3%) of non-dormant E. tasmanica seed could
germinate in the absence of fire-related cues. The most effective treatment
for promoting seed germination was direct smoke (74.67%); however,
germination with direct smoke was delayed by about two weeks when compared to
other significant treatments, suggesting an initial inhibitory effect.
Significant interactions were recorded between all classes of treatments (heat
shock, darkness and smoke solutions), with treatments acting sequentially and
additively to promote germination. The most effective combinatory treatment
tested was 5% smoked water (5%S) in conjunction with darkness
(D) and heat-shock (H) treatments (5%SDH), which raised germination
levels to 49%. In the absence of heat shock, darkness and various
concentrations of smoked water had no significant effect on seed germination.
The 5%SDH treatment promoted seed germination significantly also in two
wet-heathland (E. lanuginosa (42.7%) and
E. obtusifolia (64.7%)) and two dry-heathland
Epacris species (the Tasmanian endemic
E. apsleyensis (72.7%) and the rare mainland
Australian E. purpurascens (75%)). The results of
this study indicate that fire-related dormancy-breaking cues act
synergistically in promoting seed germination in
E. tasmanica and suggesting that their level of
influence may reflect the ecology of Epacris species.
Moisture content influences survival of cryostored seed of Banksia ashbyi (Proteaceae)
Authors: Merritt D. J. , Touchell D. H. , Dixon K. W. , Plummer J. A. , Turner D. W.
Published: December 2005

Seed survival of cryostorage (–196˚C) was examined for
Banksia ashbyi (E.G.Baker), a tree species endemic to
Western Australia. Seeds were cryostored over a moisture content range of
3–30%. Moisture contents of 18–20% significantly
depressed survival for seed of all ages tested (1 month to 13 years old).
Cryostorage at seed moisture contents below 18% did not affect seed
germination or vigour (radicle growth). Seed age influenced survival with
freshly harvested seeds showing a greater tolerance to cryostorage at high
moisture contents than older seeds. Exotherms, indicating ice formation within
seed tissues, were detected by thermal analysis at seed moisture contents
above the critical. However, there was no increase in electrolyte efflux from
seeds frozen at lethal moisture contents, suggesting the plasma membrane of
cells remained intact. This study shows that seed storage physiology of a
Western Australian species is similar to that of other orthodox species and
that cryostorage may be successfully applied for conservation of native
species without detrimental effects on germination and growth.
Patterns in longevity of soil seedbanks in fire-prone communities of south-eastern Australia
Authors: Auld Tony D. , Keith David A. , Bradstock Ross A.
Published: December 2005

Seed burial in nylon mesh bags over a 2-year period was used to examine seed
longevity patterns in 12 shrub and two graminoid species in fire-prone
habitats around Sydney, south-eastern Australia. Most species released a large
fraction of their annual seed-crop in a dormant state and all species showed
evidence for some form of persistent seedbank. However, regressions of seed
persistence over time were in most cases poor predictors of seed decay (9 of
14 study species).
Considerable variation in the degree and pattern of seed longevity was
apparent in the study species. Three functional groupings of species are
suggested. (1) Seed half-lives in the soil predicted to be greater than 2
years and evidence of imposed secondary dormancy (continuous,
Kunzea spp. or seasonal,
Grevillea caleyi). Only
Kunzea capitata and G. caleyi
showed significant seed decay in this group. (2) Seed half-lives in the soil
predicted to be greater than 2 years and no evidence of secondary dormancy
(nine species). Six species had high seed dormancy at release (only two of
which showed significant seed decay). Three species had initial seed dormancy
of 40–57%—two (Asterolasia elegans
and Zieria involucrata) with significant decay only for
the non-dormant seed fraction, and one
(Comesperma ericinum) with significant decay of both the
dormant and non-dormant seed fractions. (3) Two species
(Darwinia biflora and
Persoonia pinifolia) showed evidence of very short mean
half-lives of seeds in the soil (0.4–1.0 years). The threatened species,
D. biflora, had a rapid initial seed decay over 6 months
followed by little decay for 18 months, and the half-life of seeds is likely
to be a poor predictor of seed longevity. For
P. pinifolia, maintenance of a soil seedbank is
predicted to be dependent on continual inputs of seeds locally or dispersal of
seeds from other sites.
The Effects of Natural Disturbances on Warm Temperate Rain-Forests in South-Eastern Australia
Authors: Melick DR , Ashton DH
Published: December 2005

The effects of fire, flood and landslide disturbance on the floristics and structure of some warm temperate rainforests in East Gippsland were investigated from 1983 to 1989. Subcommunities within these forests were delineated by the numerical analyses of floristic data. In moister sites, relatively undisturbed rainforest is dominated by Acmena smithii in association with Acronychia oblongifolia and Rapanea howittiana together with numerous vines and ferns. The size-class distributions of the major tree species indicate that these forests are regenerating. In riparian habitats, Tristaniopsis laurina tends to dominate due to its greater flood resistance whereas Pittosporum undulatum becomes prominent in edaphically drier sites. Within burnt rainforest A. smithii and T. laurina have regenerated vegetatively but P. undulatum has been eliminated. In adjacent wet sclerophyll forest subsequent invasion by rainforest seedlings has occurred. In gorges, landslides may cause disturbance to various degrees and subsequent colonisation is dependent upon both the site and the matrix of the material transposed. The status of the various subcommunities is discussed in terms of the environmental gradients present, the modes of regeneration and the types of primary and secondary successions initiated by the disturbances.
Breeding System, Karyotype and Variation Within and Between Populations of Rutidosis leptorrhynchoides F Muell (Asteraceae, Inuleae)
Authors: Leeton P , Fripp YJ
Published: December 2005

The endangered plant species, Rutidosis leptorrhynchoides (button wrinklewort), is now known from only a few populations in each of two regions separated by approximately 500 km in south-eastern Australia. Plants were examined from several populations from each region. No differences in chromosome number or morphology were observed among plants or populations. All counts were diploid, 2n = 26. Viable progeny were obtained following self-pollination and allozyme analysis indicated that these progeny were the result of selfing and not agamospermy. This species is not an obligate outcrosser and does not have a classical pre-zygotic self-incompatibility system. However, outcross pollen may have an advantage over self pollen and this species may thus be preferentially outcrossing. The pollen: ovule ratios (mean 3186 ± 48.5) were consistent with this hypothesis. Allele frequencies at allozyme loci diferred little between populations, with an estimated 97% of the variation within populations. There was no correlation between genetic distance and geographic distance. In contrast, for the leaf dimensions of plants germinated and raised together in a glasshouse there were differences between plants from the two regions. It is recommended that populations from both regions should be conserved.
Geographic-Variation in Seedling Morphology of Acacia auriculiformis A-Cunn ex-Benth
Authors: Pinyopusarerk K , Williams ER , Boland DJ
Published: December 2005

Seedlings from 30 provenances from Papua New Guinea, Queensland and the Northern Territory, Australia, (and two from Thailand) were raised under common glasshouse conditions. Seventeen attributes were measured for each seedling and the resultant data subjected to univariate and multivariate analyses. Provenance differences were evident; variation amongst families within provenances was generally small. The Papua New Guinea, Queensland and Northern Territory material clustered into three distinct groups. There was a suggestion that the Queensland and Northern Territory populations were more closely related to each other than to those from Papua New Guinea. The Thai populations possibly came originally as seed from Queensland.
Genetic Determination of Erect and Prostrate Growth Habit in Five Shrubs From Windswept Headlands in the Sydney Region
Authors: Auld TD , Morrison DA
Published: December 2005

In the Sydney region, many plants from populations on windswept headlands have a more prostrate
growth habit compared with plants from populations of the same species occurring away from the
coast. To determine whether these different growth habits are genetically determined, plants from four
populations of each of five species (Acacia rnyrtifolia, Acacia suaveolens, Banksia ericifolia, Casuarina
distyla, Hakea teretifolia) were grown under uniform glasshouse conditions. Multivariate analyses of
six morphological characteristics indicate that, for four of these species, the offspring are similar to
their maternal parent; we thus conclude that the habit differences are genetically fixed in these populations.
The same trend is apparent for <I.C. distyla , although significant variation occurs in the offspring. Univariate
analyses indicate that different characteristics reflect the habit differences in different species. For
conservation biology, the implications of this intra-specific variation are that attempts should be made
to conserve viable populations of all genetically isolated taxa within a species.
Short-Term Changes in Spectral Properties of Phyllodes of Brigalow (Acacia harpophylla F Muell Ex Benth) in Response to Wetting
Authors: Yates DJ
Published: December 2005

The phyllodes of Acacia harpophylla (brigalow) possess a high reflectivity (0.20) in the visible wavelengths due to the presence of a dense covering of flattened trichomes. This results in a low value for phyllode absorptivity (0.79). While dry phyllodes appear grey-blue to the eye, wet phyllodes appear green and their reflection spectra are similar to those of 'typical' foliage elements. When wet, reflectivity in the visible wavelengths is reduced (0.09) and absorptivity is increased by 14%. Examination of the wetting and drying process, both visually and by measuring the time course of reflectivity, illustrates the importance of the wettable surfaces of both the epidermis and the individual trichomes. On drying, the reflectivity increase in the near infrared (NIR, 0.41-0.59) precedes that in the visible portion of the spectrum, although changes in the visible portion of the spectrum are larger than those in the NIR.
The Eucalypt Forest Grassland/Grassy Woodland Boundary in Central Tasmania
Authors: Fensham RJ , Kirkpatrick JB
Published: December 2005

Downslope boundaries of forest with grassland and grassy woodland occur over a wide altitudinal range in central Tasmania. Three sites were selected for study of the causes of these boundaries at low, medium and high elevations. The open vegetation was generally associated with moister and less rocky soils and more subdued topography than the adjacent forest. Frost incidence and intensity, soil moisture and waterlogging varied markedly among the three open areas. Planted tree seedlings survived 4 years in the open at all sites, and seedlings established in the open both naturally, and after sowing, where grass competition was reduced by herbicide application, digging or root competition from adult eucalypts. Grazing had no detectable effect on seedling establishment. A pot experiment demonstrated a suppressive effect of native grass swards on both seedling establishment and growth, this effect being largely independent of available moisture and nutrients. While frost, waterlogging, fire and drought may play a role in inhibiting eucalypt establishment and increasing eucalypt mortality at some or all of the sites, the dense grass swards found in all the open areas are considered to be the most likely primary agent of tree exclusion.
Germination of Verticordia Pollen After Storage at Different Temperatures
Authors: Tyagi A , Considine JA , Mccomb J
Published: December 2005

Longevity of Verticordia pollen was assessed to develop the technology necessary to allow hybridisation
of species that flower in different seasons. Pollen, either attached to the stigmatic pollen presenter
or within the anther, was desiccated and stored at temperatures from ambient to -196°C. Verticordia
pollen retained 75-80% viability at -196°C, and even when stored at room temperature for 6 months
maintained a viability of 50%.
Soil Characteristics and Tree Species Distribution in the Savannah of Melville Island, Norther Territory
Authors: Fensham RJ , Kirkpatrick JB
Published: December 2005

In the savannah of Melville Island, Northern Temtory floristic variation relates strongly to both soil
moisture regimes at different depths in the profile and chemical edaphic conditions. While some
elements of variation in vegetation structure and overstorey species composition have clear edaphic
relationships, many common tree species could be found as important overstorey components in a
range of edaphic situations. The interaction of stochastic disturbance events and phenological condition
may explain this deviation from environmental determinism.
Manipulating Agricultural Plants for a Future High CO2 Environment
Authors: Badger M
Published: December 2005

This paper discusses the potential ways in which C3 plant performance may benefit from a future high-CO2 environment. These include increases in the efficiencies for light, nitrogen and water utilisation, particularly at elevated temperatures, resulting from the improvement which will occur in the performance of the primary carboxylating enzyme, Rubisco. However, while growth experiments at elevated CO2 indicate that C3 plants show stimulation of dry matter accumulation, the potential gains are greatly ameliorated by a redistribution of plant resources. This primarily occurs via a reduction in the leaf area ratio which offsets increases in the net assimilation rate. In addition, there may be an overcommitment of nitrogen in key photosynthetic components such as Rubisco and the thylakoid electron transport system. It is concluded that plants may not be genetically adapted to optimise their growth and performance at elevated CO2 and that consideration should be given to exploring avenues for manipulating plants for more optimal responses. Targets for improvement of growth at elevated CO2 include (1) altering source-sink relations; (2) improving the redistribution of nitrogen between the photosynthetic machinery and the rest of the plant; and (3) changing the response of stomata to CO2 and humidity to increase water-use efficiency even further than is currently predicted.
Ecology of Callitris glaucophylla (Cupressaceae) on the Macdonnell Ranges, Central Australia
Authors: Bowman DMJS , Latz PK
Published: December 2005

A geographic survey of 17 stands of Callitris glaucophylla on the MacDonnell Ranges, in central Australia, revealed that the pine occurs on sites ranging from flat, sandy creek beds to rocky, north or south facing slopes, with the majority of the sampled stands occurring on steep (35°) south-facing slopes. A quadrat based (n=100) floristic survey on an outlying ridge from the MacDonnell Ranges also showed that C. glaucophylla has a wide ecological niche, although the species had a significantly negative association with sites that lacked boulders (> 0.5 m diameter) and significantly positively associated with south-facing slopes. The widespread occurrence of dead C. glaucophylla stems and the lack of associated regeneration indicate that species distribution is currently contracting. We suggest that the fragmentary distribution of the species is strongly controlled by wildfire.
A Physiological Comparison of Leaves and Phyllodes in Acacia melanoxylon
Authors: Brodribb T , Hill RS
Published: December 2005

Leaves and phyllodes of A. melanoxylon were compared in several aspects of their physiology. Changes in gas exchange and water use efficiency (WUE) under controlled conditions of vapour pressure deficit (vpd) and foliar water potential were examined. Water use efficiency in phyllodes remained constant under a wide range of evaporative demand due to high stomatal sensitivity to vpd. Leaf stomata were less sensitive to changes in vpd causing decreased WUE with increased vpd. Under water stress phyllodes survived longer and produced higher WUE than leaves. Maximum photosynthetic rates per unit foliar area were higher in phyllodes than leaves. Thus, phyllodes have a number of advantages over leaves under conditions of long and short term water stress and high irradiance. Leaves had a higher photosynthetic rate per unit of photosynthetic investment than phyllodes, suggesting that their function is to maximise growth during the seedling phase.
Patterns of Flowering and Fruit Production in a Natural-Population of Banksia spinulosa
Authors: Carthew SM
Published: December 2005

Flowering and fruiting patterns for a population of Banksia spinulosa investigated over three years exhibited a great deal of variability, both amongst plants in a given season and over seasons. Inflorescence production was greatest in 1987, reflecting an increase in numbers of plants flowering and numbers of inflorescences per plant. In contrast, infructescence numbers were similar for the three years. However, seed output was greatest in 1988, due to increased numbers of follicles per infructescence. For all years, considerably fewer inflorescences flowered late in the season. Late-flowering inflorescences also contained fewer flowers with pollen tubes, fewer pollen tubes per flower and produced fewer infructescences. Variability amongst plants was evident in the onset and timing of inflorescence production, rates of flower opening, levels of pollen tube growth and infructescence production. For example, some plants consistently had higher reproductive output than others. These plants produced seed each year, and had a greater number of mature infructescences each year and overall. The total reproductive output of these plants was approximately double that of other plants. Another group of plants never produced seed during the study, even though they flowered each year. These results illustrate the importance of considering individual variability in the population, rather than the more commonly measured, total, or mean reproductive success.
Reproductive Biology of Australian Myrtaceae
Authors: Beardsell DV , Obrien SP , Williams EG , Knox RB , Calder DM
Published: December 2005

The diverse floral structures of Australian Myrtaceae are discussed in relation to pollination biology, breeding systems, and ecological and evolutionary relationships. Although the reproductive biology of Eucalyptus has been studied widely, little is known about many of the other genera. The review concludes that additional work is needed on aspects of flower structure, pollination biota, late acting self-incompatibility, secondary pollen presentation and reproductive success.
Pollen̵1Pistil Interactions in Eucalyptus calophylla Provide No Evidence of a Selection Mechanism for Aluminium Tolerance
Authors: Egerton-Warbuton LM , Griffin BJ , Lamont BB
Published: December 2005

Selection for aluminium (Al) tolerance was assessed by studying pollen-pistil interactions in Eucalyptus
calophylla trees colonising a 30-year-old abandoned coal mine-site (soil pH 4.3) compared with
E. calophylla trees on an adjacent forest-site (soil pH 5.3). Energy-dispersive X-ray micro-analysis of
reproductive tissues demonstrated that low levels of Al occurred in the stigma, lower style and
unfertilised ovules of forest-site flowers. In contrast, significantly higher levels of Al were detected in all
reproductive tissues of mine-site flowers. Al concentrations were higher at the base of the style than in
the stigma. Al was also detected in stigmatic exudates of mine-site flowers. Selection for Al tolerance
occurred in the anther of mine-site flowers as pollen from mine-site flowers germinated six-fold (15.6%)
compared with forest-site pollen (2.6%) at the highest concentration of Al (22 ppm) used. However, the
rate of pollen tube growth was not significantly different between mine- and forest-sites at any Al
concentration. Tolerance of Al by the mine-site pollen was not shared by the progeny as there was no
increase in the survival or growth of mine-site seedlings in mine soils over forest-site seedlings.
Controlled pollinations between mine-/forest-site pollen and mine-site pistils demonstrated that there was
no significant difference in the number of mine- or forest-site pollen tubes at any level in the style in
mine-site pistils. Pollen tube abnormalities principally occurred in mine-site pistils. We concluded that
there is no evidence yet for a genetically-based tolerance of Al in E. calophylla on coal mining soils.
Early Growth of Santalum album in Relation to Shade
Authors: Barrett DR , Fox JED
Published: December 2005

Morphological features of the hemi-parasite Santalum album Linn. (Indian sandalwood) were examined on tree seedlings raised under different shade treatments. Treatment levels were full sun and 32, 50, 70 and 80% shade. The level of shade significantly affected many morphological characteristics. Leaf area was least in full sun and greater under all shade levels. Leaves were thicker, shorter and narrower in full sun than in 80% shade. Leaf length/width ratio was greater when shade exceeded 50%. Petioles were shorter in 50% and more shade. Leaves in 80% shade had more chlorophyll and were of greater weight. Stomatal numbers were higher and internodes longer in 80% shade than in full sun. None of the following showed significant differences: plant heights, leaf numbers, crown widths and stem diameters. Chlorophyll concentrations are within the range of those possessed by non-parasitic land plants. On balance 80% shade plants had adaptive attributes more favourable to growth than plants from less shade. Survival was least in full sun.
Late Cainozoic Vegetation History of North-Western Australia, From the Palynology of a Deep Sea Core (ODP Site 765)
Authors: Martin HA , McMinn A
Published: December 2005

In the late Miocene, casuarinaceous forests were predominant in north-western Australia. Through the Pliocene and Pleistocene, Casuarinaceae declined and Poaceae increased, until grasslands predominated. Acacia and some other shrub species were present, suggesting possible shrublands. Surprisingly, however, there were very few Myrtaceae; hence, eucalypt dominated vegetation was never present in this part of Australia. The present vegetation of Acacia shrublands and tussock/hummock grasslands developed, therefore, from casuarinaceous forests. The late Cainozoic palaeovegetation is compared with others of equivalent age elsewhere in Australia.
The Impact of Browsing Animals on the Stand Dynamics of Monotypic Mountain Beech (Nothofagus solandri) Forests in Canterbury, New Zealand
Authors: Jane GT
Published: December 2005

Mountain beech is frequently the sole canopy species in the montane forests of Canterbury, New Zealand and often the only significant tree or shrub present over large areas and this allows examination of a very simple ecosystem. Data from remeasurement of over 400 permanent quadrats in six areas are examined to elucidate the impact of browsing animals on natural processes. The changes in basic parameters such as stand density and basal area over a decade form consistent patterns in both visual and statistical techniques and this allows identification of important quadrats for detailed study. The basic relationship between density and basal area follows well an established semi-logarithmic relationship, even in decade by decade changes on individual quadrats. Deviations in this pattern can be related to natural disturbance events. The impact of browsing animals, mainly red deer (Cervus elaphus) varied between the different areas. Although numbers peaked in the 1930s and 1940s and declined through commercial hunting in the 1960s-1980s, the impact on the vegetation remains and will persist for many decades.
An Eocene Macroflora From the Taratu Formation at Livingstone, North Otago, New Zealand
Authors: Pole M
Published: December 2005

A macrofloral fossil assemblage from fluvial Taratu Formation sediments of Waipawan to Bortonian (Early to Middle Eocene) age, near Livingstone, North Otago, New Zealand, is described. The assemblage yielded two indeterminate coniferous taxa, thirteen taxa of angiosperm leaves, including Myrtaceae (aff. Eucalyptus, and aff. Rhodomyrtus/Rhodamnia), Proteaceae (cf. Orites excelsa), Sterculiaceae (Brachychiton populneus), Elaeocarpaceae (Sloanea), probable Lauraceae, possible Passifloraceae and two kinds of Myrtaceae reproductive structures. The original community is compared with extant vegetation in Australia and rainfall may have been seasonal.
Field Measurements of Net Photosynthesis and Related Parameters in Four Provenances of Acacia auriculiformis
Authors: Cole SP , Woo KC , Eamus D , Harwood CE , Haines MW
Published: December 2005

Tree diameter at breast height (DBH), tree height, maximum light saturated assimilation (Amax), phyllode conductance (gs), and phyllode water potential (ΨW) were determined in trees of Acacia auriculiformis A. Cunn. ex Benth., 3-4 years old. Trees from three provenance regions were studied: from Papua New Guinea (PNG ̵1 Bensbach River and Morehead River provenances); north Queensland (NQ); and the Northern Territory (NT), as part of a provenance trial on Melville Island, Northern Territory. The PNG provenances were the largest trees and had accumulated the largest biomass. Significant variation in Amax between provenance regions within a season, and between seasons (wet vs dry) for each provenance region were observed. There was no correlation between seasonal Amax and provenance region growth rate. The NT provenance region generally exhibited the largest Amax and the least variation between seasons and the PNG provenance region the lowest Amax, while the NQ provenance region varied most between seasons. Seasonal and provenance region Variation in gs followed a similar trend to Amax. There was no significant variation in ΨW between provenance regions. Canopy area of the PNG provenances was seven times greater than that of the NT provenance during the late dry season. We conclude that PNG provenances achieve their larger growth rates primarily by maintaining a larger canopy. Results are discussed with reference to the observed superior growth rate of the PNG provenances, and highlight the need for caution in extrapolating single phyllode assimilation data to infer comparative growth rates.
Natural Grassy Vegetation and Native Forbs in Temperate Australia: Structure, Dynamics and Life-Histories
Authors: Tremont RM , Mcintyre S
Published: December 2005

This paper describes aspects of the structure, floristics and dynamics of natural grassy vegetation in temperate Australia. The community structure of this vegetation type can be conceptualised using a matrix-interstitium model which may be useful in studies of the dynamics of forb populations and the role of disturbances in grassland management. Disturbance alters the balance between the matrix and interstitial components and is important for herbaceous communities as an agent in changes to, and losses of, native species. Life history characteristics conferring tolerance of disturbance upon native forbs are discussed, and the ruderal nature of the exotic component is suggested as a characteristic leading to the replacement of native forbs by exotic species, where substantial exogenous disturbance occurs. Despite the demonstrated importance of exogenous disturbances in influencing native species diversity and exotic invasions, there is still a poor understanding of the specific and interactive effects of various disturbances and the roles of particular plant traits in determining forb survival. Further research, utilising comparative or functional group approaches, is required to explain responses of natural grassy communities and native forbs. Such studies would provide opportunities for developing ecological theory and improving the management of natural grassy communities and their native forbs.
Seed Dormancy and Germination Mechanisms in Eremophila (Myoporaceae)
Authors: Richmond GS , Ghisalberti EL
Published: December 2005

Eremophila R.Br. (Myoporaceae) species are hardy perennial shrubs and trees which are endemic to Australia. They offer potential in revegetation and horticultural programmes and are currently propagated from cuttings, since they have proven difficult to grow from fruits. Fruits of E. maculata (Ker Gawl.) F.Muell. contain multiple seeds, and potential seed viability decreases from 58-74% over the first 3 years to 8% after 10 years. Up to 98% germination is obtained with seeds of E. maculata excised from the fruit, compared to 28% germination from the fruit. Since older fruits, which are characterised by a weathered fruit apex, allow a greater number of seedlings to emerge during optimum conditions, Eremophila germination appears to be controlled primarily by physical dormancy due to the woody endocarp which surrounds the seeds. Chemical dormancy also plays an important role in the establishment of Eremophila, and germination inhibitors have been found within the fruit wall of E. maculata and E. racemosa (Endl.) F.Muell. The inhibitors from E. maculata appear to be water-soluble aromatic glycosides. It is suggested that germination in the field is triggered by leaching of these compounds from the fruit during intense precipitation.
The Effects of Herbivory by a Mite, Aculus hyperici, and Nutrient Deficiency on Growth in Hypericum Species
Authors: Willis AJ , Ash JE , Groves RH
Published: December 2005

The combined effects of herbivory by a mite, Aculus hyperici Liro, and a deficiency of nutrients on
plant growth were measured for Hypericum perforatum L. and H. gramineum J.Forst. grown in a
glasshouse. The results are discussed in relation to the biological control of H. perforatum, an
introduced weed in southern Australia, relative to growth of its indigenous congener, H. gramineum.
Growth of both species was reduced when infested with the mite, although the growth of H. perforatum
was reduced by more than that of H. gramineum. Nutrient deficiencies also reduced growth of both
species, especially of roots. Imposition of nutrient deficiency on mite-infested plants caused
multiplicative reductions in plant growth equivalent to the product of the proportional reductions caused
by either herbivory or nutrient deficiency alone.
Susceptibility of Selected Tasmanian Rare Plants to Phytophthora cinnamomi
Authors: Barker PCJ , Wardlaw TJ
Published: December 2005

Forty-seven species native to Tasmania were tested for their susceptibility to Phytophthora cinnamomi. Plants were propagated from cuttings and or seed. The plants were root inoculated by irrigating the moist growing medium with infected broth. Individuals in 36 species proved to be susceptible, four species were resistant hosts, three species resistant and four species returned inconclusive results. Epacris contained the most suceptible species and the level of susceptibility varied considerably within the Epacris, but also in Acacia and Pultenaea. Species from a number of genera contained an apparently resistant element.
Seed Longevity of Six Native Forbs in a Closed Themeda triandra Grassland
Authors: Lunt ID
Published: December 2005

Seeds of six native forbs̵2Arthropodium strictum R.Br., Burchardia umbellata R.Br., Bulbine bulbosa (R.Br.) Haw., Chrysocephalum apiculatum (Labill.) Steetz, Craspedia variabilis Everett & Doust and Leptorhynchos squamatus (Labill.) Less.-were sown on and below the soil surface in a closed, native grassland dominated by Themeda triandra Forsskal. Replicate seed lots were recovered after 2, 4, 6, 9 and 12 months, and viability was assessed. Less than 7% of sown surface seeds of B. bulbosa, B. umbellata, C. variabilis and L. squamatus, and less than 10% of buried seeds of A. strictum, B. umbellata and C. variabilis remained viable after 12 months. Virtually all losses of Liliaceae seeds were due to germination. Fates of Asteraceae seeds were difficult to assess accurately after 6 months, but germination accounted for most seed losses. Burial significantly promoted longevity of B. bulbosa, C. variabilis and L. squamatus seeds. No obvious relationship existed between seed longevity and taxonomic group (Liliaceae versus Asteraceae) or seed mass, for surface or buried seeds; the response of the large-seeded lily, B. bulbosa, was most similar to that of the small-seeded daisy, L. squamatus. Of the six species, C. apiculatum appears to have the greatest potential to accumulate a soil seed bank beneath a closed grass canopy, owing to its small seed size, inhibition of germination beneath a closed canopy, both on and below the soil surface, and sustained viability of buried seeds. Naturally dispersed seeds of the other five species are likely to form smaller, transient or short-term seed banks.
The Mating System and Genetic Diversity of the Australian Arid Zone Mallee, Eucalyptus rameliana
Authors: Sampson JF , Hopper SD , James SH
Published: December 2005

Estimates of parameters of the mixed mating model were made for three populations of the bird-pollinated arid zone eucalypt, Eucalyptus rameliana F. Muell. Levels of outcrossing ((t) over cap) varied significantly between populations from mixed mating with substantial selfing ((t) over cap = 0.54) to almost completely outcrossed ((t) over cap = 0.95). Comparison of single-locus and multilocus estimates suggested that the drop in outcrossing was due to increased self-pollination. The lowest outcrossing rate was attributed to the reduced ability of a population with low numbers of buds to attract bird pollinators. Outcrossing rates in E. rameliana are proposed to be a more direct reflection of pollination than estimates made for mass flowering, i.e. small-fruited eucalypts. The distribution of allozyme diversity in E. rameliana also appeared to reflect the impact of bird pollinators in promoting gene flow as well as the species capacity for outcrossing and introgression. Levels of diversity were comparable with other eucalypts, but the proportion of diversity between populations (GST = 9.2%) was only about half the mean for other eucalypts. Genetic distances between populations were low, but there was same significant differentiation of populations which was attributed to non-random bird migrations. The importance of bird pollination in the mating system and the distribution of genetic diversity in E. rameliana emphasises that enough habitat to support nomadic birds should be preserved in order to conserve this eucalypt species.
An Efficient in vitro Regeneration System for Australian-Grown Chickpea (Cicer arietinum) Cultivars
Authors: Adkins AL , Godwin ID , Adkins SW
Published: December 2005

A comparison of methods for efficient in vitro regeneration of Australian-grown chickpea (Cicer arietinum L.) cultivars was undertaken. The most efficient regeneration system was one where immature cotyledon and embryonic axis explants, 14-21 days post-pollination, were cultivated on Murashige and Skoog's salts with Gamborg's vitamins, 1.0, 3.0 or 5.2 mg L-1 zeatin, 0 or 35 μg L-1 indole-3-acetic acid, 30 g L-1 sucrose and 8 g L-1 Phytagar. The first embryoid structures appeared after 2 weeks of culture at 25 ± 1°C in dim light (150 μmol m-2 s-1) and formed directly on the edges of the immature cotyledons or petiole stumps. Between 10 and 20 structures were produced on each cotyledon explant in two cultivars, however, the embryogenic structures which developed on cv. Narayen were more efficiently transformed into shoots than far cv. Amethyst. An efficient regeneration medium (2 mg L-1 naphthaleneacetic acid, 1/2 Murashige and Skoog's salts with Gamborg's vitamins, and 0.5 g L-1 activated charcoal) was used to develop a portion of the shoots into morphologically normal plants growing in a vermiculite and soil potting mix in a growth room. Less efficient in vitro regeneration was observed when hypocotyl and shoot sections, and shoot apices were induced to form callus and plants by organogenesis. These plants could not be established in a potting mix. The amount and type of callus produced varied between explant type and cultivar.
Effects of Four Low-Intensity Burns Over 14 Years on the Floristics of a Blackbutt (Eucalyptus pilularis) Forest in Southern Queensland
Authors: Russell MJ , Roberts BR
Published: December 2005

A grassy open forest of Eucalyptus pilularis Smith, E. saligna Smith, and other eucalypts, with an understorey of Allocasuarina torulosa (Aiton) L.A.S.Johnson and Acacia spp., was studied by belt transect for 14 years. The forest, north of Toowoomba in Queensland, was divided by a fire break into a non-burned section and a section that had a low-intensity prescribed burn through it four times over the observation period. Cover of herbaceous species, measured with the intercept method, and density of perennial species were recorded six times in the burned section and seven times in the non-burned section over the observation period. There was no difference between burning treatments in cover or density of the species sampled nor in their diversity (Shannon index) over this period. Classification analysis of data sets of the whole transect did not show clear groups and ordination of these data sets produced axes related to distribution of major species. These analyses indicated spatial variability along the transect as was apparent in the field. Total cover of the main grass species confirmed this variability, but also showed changes in parts of the transect over the period that were ascribed to changes in cover of the shrub layer. Data suggested that low-intensity burning stimulated ecesis of Acacia spp. but did not affect density of Allocasuarina torulosa (Aiton) L.A.S.Johnson and young eucalypts in this forest. Burning kept Lantana camara L. bushes small compared with not burning. Covers of the major grasses, Microlaena stipoides (Labill.) R.Br., Themeda triandra Forssk and Imperata cylindrica (L.) Rauschel, were not different between burning treatments. It appears that low-intensity prescribed burning produced less change over the 14 year period than did no burning. Change in the non-burned section may be attributed to encroachment of the exotic species Lantana camara. This situation is discussed in relation to recent plant succession theory.
Fire, Buried Germinable Seed Banks and Grass Species Establishment in an Urban Eucalypt Forest Reserve
Authors: Odgers BM
Published: December 2005

The buried germinable seed banks of two natural contrasting savanna open-forest sites were investigated before and after a wildfire. It was found that while the number of buried germinable grass and sedge seeds remained the same, the number of buried germinable dicotyledon seeds in both sites increased after the fire. It was also found that there were similar species of grasses present in the buried germinable seed banks before and after the fire. When germinating grass seedlings in the burnt and unburnt sites were compared, similar species of grasses were found in the germinating seedlings at both sites; however, more grass seedlings germinated in the burnt site than in the unburnt site.
Growth and Fire Response of Selected Epacridaceae of South-Western Australia
Authors: Bell TL , Pate JS
Published: December 2005

Recruiting populations of seeder (Astroloma xerophyllum (DC.) Sond. and Leucopogon conostephioides DC.) and resprouter (Leucopogon verticillatus R.Br. and Conostephium pendulum. Benth.) epacrids were examined over an 8 year period, using time of fire, shoot morphology and root xylem ring number to age plants. The seeders commenced flowering earlier, achieved three-fold higher shoot:root ratios but accumulated much smaller root starch reserves than the resprouters. The resprouting potential of L. verticillatus was 'bud initiation-limited', since progressive shoot removal exhausted the bud-producing potential but did not fully deplete the starch reserves of the root stock. Apparent conversion efficiency of starch to new shoot biomass was 88%. The corresponding response in C. pendulum was 'energy reserve-limited', with shoot removal eliminating root starch but leaving many unexpanded buds. Dendroecological analyses of root xylem growth rings were undertaken on 15 year-old plants of C. pendulum recruiting from seed in unburnt and adjacent periodically burnt habitats. Growth ring extension of burnt plants resumed after each fire at rates faster than their unburnt counterparts, suggesting that improved access by resprouting shoots to light, water and nutrients compensated for destruction of the previous shoot system.
The Disappearing Grassy Balds of the Bunya Mountains, South-Eastern Queensland
Authors: Fensham RJ , Fairfax RJ
Published: December 2005

The physical setting of 61 grassy balds on the Bunya Mountains in south-eastern Queensland was surveyed during 1995, and a further 73 balds were assessed from aerial photographs taken in 1951 and 1991. Balds were analysed to search for consistent environmental patterns that may account for their existence. There was little association between measured environmental variables (including altitude, surface rock cover, slope, landscape position, surrounding vegetation, bald area) and the occurrence of balds, although large balds have a weak association with steep slopes and relatively low rock cover. Grassland was on shallower soil than forest. Some, but not all balds were surrounded by rainforest. No consistent relationship was evident for all measured balds surrounded by eucalypt forest. About 26% of the area of balds existing in 1951 had been invaded by forest by 1991. The extent of the invasion was generally higher for balds surrounded by eucalypt forest than balds surrounded by eucalypt and rainforest or rainforest only, but showed little relationship with other environmental variables. The invading tree species groups could not be associated with environmental variables. The lack of environmental correlation of bald location and size, and the rapid change in bald area is not supportive of hypotheses relating bald maintenance to intrinsic physical conditions. There is relatively poor species diversity of Eucalyptus on the Bunya Mountains and this narrow ecological range of species may be a limitation on the colonisation of the grasslands. Indirect evidence for the role of grazing and fire as agents of bald maintenance are discussed, and it is concluded, that fire, and not grazing, is likely to be a major influence.