bluuebunny/crossref_metadata_2025_split huggingface dataset:
The ground parrot (Pezoporus wallicusKerr) in south‐eastern Australia: a fire‐adapted species?
Authors: MEREDITH CHARLES W. , GILMORE ALEXANDER M. , ISLES ANDREW C. 
Published: July 2006

AbstractThe ground parrot(Pezoporus wallicus)has a coastal distribution in Victoria and has declined in range since European colonization. Its habitat consists of two major vegetation communities: coastal heathland and sedgeland. These are further divided into various sub‐communities. These habitats contained high densities of cyperaceous and restionaceous plants, the seeds of which form the bulk of the bird's diet. Seeds and small fruits of some dicotyledonous plants and grasses are also eaten. Seed production by sedges remains fairly constant over time in sedgelands but varies in heathland, depending on time since burning. This variation is reflected by parallel changes in ground parrot population density. Both long unburnt and very frequently burnt heathlands are unsuitable for ground parrots. The birds also require dense vegetation cover.Ground parrots appear to live in territorial breeding pairs with enforced natal dispersal. This is an adaptation to an environment where habitat is patchily distributed in space and variable in quality over time.
The interaction of density and resource levels in monospecific stands of plants: a review of hypotheses and evidence
Authors: MORRIS E. C. , MYERSCOUGH P. J. 
Published: July 2006

AbstractThe series of asymptotic yield‐density curves traversed by even‐aged monospecific stands of plants at the same resource level is described by the function f(wmax y max), where wmax= spaced plant weight and ymax= maximum yield possible at high densities. If the resource level at which the stands are grown is reduced, two sets of outcomes are possible. The stands at the decreased resource level may show essentially the same crowding effects as the control stands, but at a slower rate (altered‐speed hypothesis). This hypothesis implies a common family of yield‐density curves and a common thinning line for stands at different resource level may occur not only at a different rate at a harvest in the stands of higher growth. Alternatively, crowding effects at a reduced resource level may not only occur at a different rate to the controls but take a different course, leading to more intense crowding effects at a harvest being observed in the stands of lower growth (altered‐form hypothesis). Thus a different family of yield‐density curves and different thinning lines would apply at each resource level. For yield‐density curves, the altered‐speed hypothesis applied if f(wmax, ymax) is the same at each resource level. If this function differs with resource level, the altered‐form hypothesis applies at a harvest provided the ratio ymax/wmax is less at the low resource level. Cases intermediate between these two hypotheses may occur. For thinning lines differences in the position of the non‐thinning/self‐thinning boundary and in f(wmax, ymax) can affect the intercept and slope of thinning lines. The theoretical magnitude of these differences are discussed. Examples of both hypotheses are reviewed. For the altered form cases differences in non‐thinning crowding effects between resource levels are capable of causing significant differences in thinning lines.
Acari and Collembola in the litter and soil of three north Queensland rainforests
Authors: HOLT J. A. 
Published: July 2006

AbstractThe population changes, distribution and composition of litter and soil Acari and Collembola from three north Queensland rainforests are described based on samples collected on six occasions at approximately 3‐monthly intervals. Numbers of Acari and Collembola collected from litter were lower in the north Queensland rainforests than those reported from rainforests outside Australia: however, numbers of Acari and Collembola in the soil were similar to numbers in rainforest soils elsewhere.Cryptostigmata were the most abundant group of Acari in the litter and 0–4 cm soil layer, comprising 41–55% and 42–55% of the total Acari in the litter and 0–4 cm soil layers respectively. Most of the Acari and Collembola are located in the 0–4 cm soil layer at each site (53–75%), with the litter layer containing the smallest proportion (3–20%). Most of the groups of Acari and Collembola examined show little evidence of seasonal vertical migration between the litter and soil to 8 cm. Minimum numbers of Acari and Collembola in the litter occurred in the dry season and maximum numbers occurred in the wet season. Seasonal fluctuations in numbers of Cryptostigmata appear to be influenced by the periodic saturation of the soil during the wet season.
Seasonality of insect abundance in an Australian upland tropical rainforest
Authors: FRITH CLIFFORD B. , FRITH DAWN W. 
Published: July 2006

AbstractMonthly light and Malaise trap catches, taken over 31 months, were used to examine seasonal and annual changes in the abundance of predominant orders of upland tropical rainforest insects. Insect numbers and biomass increased during the late dry season, reached a peak during the wetter months, and declined during the early dry period. Fluctuations in insect abundance appeared to relate to (1) climatic factors such as length and severity of the dry season, or amount and period of rainfall; and (2) food availability such as an increase in the production of new leaves, or flowering and fruiting periodicity.
The relationships among eucalypt forest, grassland and rainforest in a highland area in north‐eastern Tasmania
Authors: ELLIS R. C. 
Published: July 2006

AbstractChanges in the vegetation of a highland area of north‐eastern Tasmania are described and related to a change 150 years ago from Aboriginal to settled land use. Expansion of rainforest dominated byNothofagusinto areas previously dominated byEucalyptus, and ofEucalyptusforest on to grassland that occupied former rain ‐ forest areas is accounted for by local differences in frequency and severity of fires since about 1835.Successional relationships amongst 12 vegetation types are defined, and discussed in relation to three models of vegetational succession.
Towards a definition of ecological disturbance
Authors: RYKIEL EDWARD J. 
Published: July 2006

AbstractThe terms disturbance, perturbation, and stress have been used in various ecological contexts, often synonymously, inconsistently and ambiguously. Consequently, the meaning of these terms lack any ecological rigor upon which to construct a coherent theory of ecosystem response to disturbance. Herein are some of the semantic and conceptual problems involved in defining disturbance, perturbation and stress, and proposals of working definitions as a basis for further discussion.
An experimental investigation of patch use by female monarch butterflies, Danaus plexippus (L.)
Authors: BULL C. M. , ZALUCKI M. P. , SUZUKI Y. , MACKAY D. A. , KITCHING R. L. 
Published: July 2006

AbstractMonarch butterflies, which breed throughout the year in southeastern Queensland, Australia, were studied in four dense milkweed patches during the winter months (June‐August) 1983. The percentage of marked females recaptured was measured in each of four 15‐day sampling periods. In patches where males were experimentally removed, female recapture rate decreased compared with patches which had the same density reduction but no change in sex ratio. There was a significant correlation between female recapture rate and the proportion of males in samples, but female recapture rate was not correlated with population density, the number of males, the number of females or the proportion of young butterflies in the samples. We propose that females assessed patch quality by the sex ratios, and left a patch sooner if encounter rate with males was low. Since males provide a nutrient ‘reward’ during copulation, they may be a limited resource for females during winter. An alternative interpretation, that females left a patch sooner when female density was higher, was not supported as strongly by the data.
Relationships between litterfall rate, litter mass and decomposition rate in Eucalyptus forests in southeastern Australia
Authors: HUTSON BARRY R. , VEITCH L. G. 
Published: July 2006

AbstractMeasurements of annual litterfall rate and mean annual litter mass for various indigenous open‐forests are listed, along with the consequent decomposition constant (k) and mean annual rainfall.Using data only from sites considered valid for comparison (i.e. all those with a sclerophyllous plant understorey, not recently burnt, grazed or invaded by an exotic decomposer, and where for accuracy of assessment the litter layer has been sampled on several occasions) a quadratic relationship between litterfall rate and litter mass was significant, with decomposition rates at sites increasing with increasing litterfall rate.The existence of such a relationship may be useful for future studies: if litter data obtained lie appreciably outside the values on the line of quadratic regression, it would be worthwhile checking the accuracy of litterfall and mass estimates, site past history and the validity of the decomposition constant estimate.There was a significant positive linear relationship between the decomposition constant and mean annual rainfall at sites where rainfall was within the range 600–1800 mm y‐1, the general limits for open‐forest site development. However, more data are required to increase the predictive value of relationship.
The organization of a honeyeater community in an unpredictable environment
Authors: McFARLAND DAVID C. 
Published: July 2006

AbstractThe honeyeater community of an open‐layered forest was studied in the New England National Park over a 2.5 year period. Various aspects of honeyeater behaviour (aggression, social and foraging) were examined during transects and by use of time‐budgets. Time‐budgets were used to estimate the daily energy requirements for each species. Since nectar availability in the study area was variable, the energy produced per day by the nectar sources was occasionally insufficient to meet the daily energy demands of the honeyeater community. No strong spatial partitioning of the nectar resources by the birds was found. Use of the resources appeared to be based primarily on dominance interactions (interspecific aggression), with the larger species tending to dominate the smaller ones. Smaller species survive in the area because of their behavioural attributes and greater foraging efficiency which enables them to use the sparse supply of nectar on poor days. Temporal gradients in nectar richness may be just as important as spatial gradients in permitting the coexistence of species which use the same resource in the same habitat. Most of the results from this study fail to support the predictions made elsewhere concerning the organization of communities in unpredictable environments.
Soil seed‐bank components of the northern jarrah forest of Western Australia
Authors: VLAHOS STEPHEN , BELL DAVID T. 
Published: July 2006

AbstractThe germinable soil seed‐store of the northern jarrah (Eucalyptus marginata Donn ex Sm.) forest was found to average 767 seeds m−2 (range:377–1579 seeds m−2) over six randomly selected plots within a range of forest sites. A total of 68 different taxa of vascular plants were recognized following heating and glasshouse tray germination tests of field‐collected soils. Both the qualitative and quantitative composition of the soil seed‐bank were dominated by annuals and sub‐shrubs. Because less than 10% of the seed of the soil was from species of the dominant tree and woody shrub strata, there were major floristic differences between the existing flora and the composition of the soil seed‐bank. The influences of the soil seed‐bank on rehabilitation of disturbed jarrah forest lands and current fire management are discussed.
Population dynamics of the shrub Acacia suaveolens (Sm.) Willd.: Seed production and predispersal seed predation
Authors: AULD TONY D. , MYERSCOUGH PETER J. 
Published: July 2006

AbstractSeed production and predispersal seed predation in the shrub Acacia suaveolens were examined over 3 consecutive years in eight populations in south‐eastern Australia. Seed‐crop sizes varied both between and within populations of different ages. Seed production was maximal in the first one to four flowering seasons after establishment, and then declined with plant age. The size of the annual seed‐crop was also influenced by rainfall for that year.Predispersal seed predation varies between populations over fruiting seasons with the initial large seed‐crops resulting in predator satiation. Within one fruiting season, no significant variation in the extent of predispersal seed predation was found in any of three populations studied. There were two major forms of predispersal seed loss: toss of whole fruits to Melanterius corosus (Coleoptera: Curculionidae) and external insect seed grazers, and loss of individual seeds within fruits to M. corosus. Exclusion experiments showed that seeds lost to these predispersal seed predators would otherwise have been matured by the parent plant. The effects of predispersal seed predation cannot be directly related to seedling recruitment. Indirectly, such predation may influence the dispersion of seeds in the soil profile and hence, subsequent recruitment.
On comparing herbivore damage in Australian and north temperate systems
Authors: FOX L. R. , MORROW P. A. 
Published: July 2006

AbstractTwo recent reports suggested that Eucalyptus trees in Australia sustain less insect damage than previously reported (Ohmart 1984; Ohmart et al. 1983a). Those conclusions were based partly on new data and partly on a survey of reports describing herbivory in Australian and in northern forest ecosystems. In this paper the present authors argue that the logic and data interpretations in Oh mart (1984) and Ohmart et al. (1983a) are flawed, and a re‐evaluation of arguments and existing data about levels of herbivory is presented.We also discuss several broader issues raised by this dispute. In particular, we emphasize that the variability that troubles some investigators is a fundamental component of the ecological and evolutionary processes in these systems. This variability generates differences in patterns that are not the result of inaccurate techniques nor of biased observers. It is argued, further, that it is not possible to predict the ecological or management consequences of either large or small amounts of herbivory from assessments of mean levels in natural systems.
Development of a new piosphere in arid chenopod shruhland grazed by sheep. 1. Changes to the soil surface
Authors: ANDREW MARTIN H. , LANGE ROBERT T. 
Published: July 2006

AbstractPiospheres, that is, zones of attenuating stocking impact extending out from watering places, are a feature of arid pastoral regions. The present authors studied, for the first time, the initial development of a piosphere in respect of a number of variables of the soil surface. The site was near‐pristine chenopod shrubland, part of a paddock of 1340 ha near Whyalla, South Australia, stocked with ca. 200 sheep on a new watering point. Soil features monitored over the first 2.5 years were dung deposition, sheep track development and surface erosion, the soil lichen crust, compaction of the soil surface and dustfall, using fenced plots of at least 550 m2 as controls.Piosphere patterns (i.e. patterns reflecting the concentricity of stocking pressure around water) were manifest within the first 3 months for sheep dung deposition, sheep track development, and lichen cover. Soil compaction, which was confined to sheep tracks and then largely to the surface 5 cm, displayed a piosphere pattern when it was first recorded 6 months after stocking. Bulk density of this layer was elevated by up to 20%. There was only a weak piosphere pattern in dustfall. The piosphere patterns in sheep track development and destruction of the lichen crust became more pronounced in time. Track direction was near radial. After 2 years the limit of the piosphere pattern ranged from ca. 10 m from the trough for infiltration into dry soil after an abrupt rainstorm, to greater than 800 m for sheep track intensity. These changes occurred at stocking levels amongst the lowest in Australian arid zone pastoral situations.After the first 9 months of sheep stocking there was no discernible effect of grazing on the density of the short‐lived grasses or on the pattern of kangaroo arid rabbit activity as judged by the pattern of their dung deposition. No discernible erosion of the soil surface other than in sheep tracks occurred during the first 2 years.
Insect herbivory on mangrove leaves in North Queensland*
Authors: ROBERTSON A. I. , DUKE N.C. 
Published: July 2006

AbstractEstimates of leaf damage by insect herbivores are presented for 25 species of mangrove plants, comprising canopy and understorey species. Leaf area loss was highly variable among the species sampled, with means ranging from 0.3 to 35.0% of expanded leaf area. There was also great variability amongst leaves within species, and the mean coefficient of variation for leaf loss from the 25 species was 266%. Of the 12 species sampled at more than one site in North Queensland, eight exhibited small, but significant, between‐site differences in herbivory. In general, it did not appear that height in the canopy influenced herbivory. For the dominant mangrove forest community type at Missionary Bay, an estimated mean of 2.1% of leaf production, or 11 g m‐2 per year, entered the direct grazing pathway. This very low figure is compared with estimates from other studies on mangrove forests and estimates from a variety of Australian terrestrial forests.
Interrelationships among some ectomycorrhizal trees, hypogeous fungi and small mammals: Western Australian and northwestern American parallels
Authors: MALAJCZUK N. , TRAPPE J. M. , MOLINA R. 
Published: July 2006

Abstract Species of the hypogeous fungus genus. Mesophellia have been shown to form ectomycorrhiza with Eucalyptus diversicolor and improve seedling growth. Since the morphology of these fungi increases their dependence on animal mycophagy for spore dispersal, these results imply a tripartite interrelationship between eucalypts, hypogeous fungi and marsupials which parallels the North American interrelationship between ectomycorrhizal pine, hypogeous fungi and rodents. An understanding of the independent but analogous interrelationships on the two continents has implications for forest management, especially in regard to the effects of forest conversion on other members of the ecosystem.
A transect study of the Eucalyptus forests and woodlands of a dissected sandstone and laterite plateau near Darwin, Northern Territory
Authors: KIRKPATRICK J. B. , BOWMAN D. M. J. S. , WILSON B. A. , DICKINSON K. J. M. 
Published: July 2006

AbstractTabletop Mountain in the Northern Territory is a sandstone plateau topped in part by a residual laterite soil. The vegetation of the plateau was mapped and transects placed to cover the mapping units in which eucalypts were dominant or shared dominance. A polythetic divisive classification of the transect floristic data was largely congruent with the mapping units, which also differentiated the dominants. Topography and soils have an apparently strong influence on the nature of the vegetation through their influence on the periodicity and intensity of drought and Waterlogging. However, differences in soil fertility and understorey flammability are postulated to be important in discriminating several of the mapped vegetation types. The flora of Tabletop more closely resembles that of the Alligator Rivers region than that of the Mitchell Plateau or Weipa. Some of the communities differentiated at Tabletop are related floristically to some of the communities differentiated in the Alligator Rivers region and at Gove.
Flower colour change inBanksia ilicifolia: A signal for pollinators
Authors: B.LAMONT BYRON , COLLINS BRIAN G. 
Published: July 2006

AbstractBoth birds and insects visit yellow flower heads ofBanksia ilicifoliarather than those in the pink or red phases. Birds carry most pollen. Substantial nectar and pollen rewards are present only in the yellow phase. The timing of flower colour change also corresponds to a decline in viability of presented pollen and stigma receptivity. Colour change is age‐dependent rather than pollinator‐induced. Bird visits to yellow or red heads are essentially determined by the availability of nectar in each rather than differences in their visibility. Fruit set is negligible in the absence of pollinators but still < 1% in their presence.Banksia ilicifoliahas the smallest heads and is the most localized of five co‐occurring and partly co‐floweringBanksiaspecies. It is hypothesized that the restriction of flower colour change toB. ilicifoliaincreases the competitiveness of this species: bird visitors are directed to flower heads with abundant nectar, viable pollen and receptive stigmas, foraging and pollination efficiency thereby being enhanced without a marked reduction in long‐distance attractiveness of the tree to potential pollinators.
Pollination biology in the Snowy Mountains of Australia: Comparisons with montane Colorado, USA
Authors: INOUYE DAVID W. , PYKE GRAHAM H. 
Published: July 2006

AbstractVarious aspects of the pollination biology of the alpine flora of Kosciusko National Park, NSW, were examined from late December 1983 until the end of March 1984, including flowering phenology, corolla tube lengths, flower colour, ultraviolet reflectance patterns, visitation rates to the flowers and proboscis lengths of the flower‐visiting insects. An average of 5.3 species flowered in each of 13, 2 m×2 m montane plots and 5.6 species in the 13 alpine plots. The maximum number in flower simultaneously averaged 4.1 species in the montane and 3.3 in the alpine plots; flowering peaked in mid‐January, Corolla tube lengths of the flora averaged 1.73 mm.The most common floral colour was white or predominantly white (40 species), followed by yellow (14 species). Only six of the 38 species (16%) examined had some type of reflectance pattern; the remaining species all absobed ultraviolet.Flies appeared to be the major pollinators. The insects collected in the study area comprised 60 species of Diptera, 33 species of Hymenoptera, and several species each of Lepidoptera and Coleoptera. On average, 14.4% of flowers watched during 379 observation periods (10 min each) were visited. On average, each plant species was visited by 6.4 species of flies, 2.4 species of bees, wasps or sawflies, one species of butterfly or moth and 0.3 species of beetles. Visitation rates increased over the growing season, and were significantly affected by ambient temperature (positively), light levels (positively) and wind speed (negatively).The maximum proboscis length for the 25 most common species of bees was 2.76 mm, but 18 of 51 species of flies had proboscis lengths longer than this. The mean proboscis length for all 25 species of bees was 1.68 mm, and for 51 species of flies was 2.31 mm. Proboscis lengths for flies were positively correlated with the average corolla length for the plant species they visited. For bees, however, the range in proboscis lengths was relatively small and did not show this pattern.There appear to be significant differences between the plant‐pollinator community of alpine Australia and other alpine areas where bumblebees are common pollinators. These differences include shorter proboscis and corolla tube lengths, and perhaps an increased diversity and significance of flies as pollinators.