bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biology of the gumleaf skeletoniser, Uraba lugens Walker (Lepidoptera: Noctuidae), in the southern jarrah forest of Western Australia
Authors: Farr Janet D 
Published: March 2003

AbstractThe biology of Uraba lugens Walker, gumleaf skeletoniser (GLS), in the southern
jarrah (Eucalyptus marginata Donn ex Smith) forest of Western Australia is
examined with respect to: (1) distribution of egg rafts and larvae in the host canopy;
(2) survival on different food plants; (3) phenology; (4) mortality; and (5) fecundity.
Limited preference for height was found for eggs and larvae within the jarrah canopy.
Both jarrah and marri (Corymbia calophylla (Lindl.) K.D. Hill and L.A.S. Johnson)
were intermediate hosts within the host range for GLS when compared with more preferred
hosts from eastern Australia. A simulation model, used to determine phenology, showed
GLS to be bivoltine in Perth and univoltine in the southern jarrah forest near Manjimup,
with capacity for the univoltine form to change to a bivoltine cycle following two
consecutive warm winters. Six parasitoids were isolated from populations in south‐west
Western Australia. The eulophid Euplectrus sp. and an unknown mortality agent were the predominant causes of the population decline in 1988, following an outbreak during 1982–88. Fecundities were significantly different between the outbreak and non‐outbreak periods. Furthermore, fecundity for the southern jarrah forest population was significantly higher than measured fecundities of bivoltine South Australian populations.
River flows and estuarine ecosystems: Implications for coastal fisheries from a review and a case study of the Logan River, southeast Queensland
Authors: Loneragan Neil R. 
Published: March 2003

AbstractRiver discharge has long been recognized as one of the factors that contributes to the high productivity of estuaries. Although there is little evidence that river inputs of terrestrial carbon make a direct contribution to coastal food webs, such exported nutrients may stimulate in situ production in estuaries and thus enhance the survivorship and growth of fish and crustaceans in these systems. Furthermore, fluctuations in salinity and turbidity may influence the extent of available habitat for fish and crustaceans and therefore their distribution and/or catchability. Despite these potential links between flow and the secondary production of estuaries and coastal waters, there is still a common perception that ‘water going to sea is wasted’ and a continuing trend to regulate the flow of rivers. We review the evidence for links between river flow and the productivity of estuarine/coastal fisheries, drawing on a case study of the Logan River in southeast Queensland, and explore the potential mechanisms for these linkages. Our research, and that of others, confirms that high river discharge can have a strong positive effect on the production of commercial and recreational coastal fisheries. It also shows that the seasonal pattern of flow is equally, if not more important, than the magnitude of flow. River regulation is likely to have a dramatic effect on the production of coastal fisheries and, given the current pressures for water resource development, this is an important avenue for future research and evaluation.
Ecology of benthic macro‐invertebrates in soft‐sediment environments: A review of progress towards quantitative models and predictions
Authors: Constable Andrew J. 
Published: March 2003

AbstractThis paper reviews the ecology of soft‐sediment macro‐invertebrates and, in particular, evaluates how much progress has been made in the recent literature towards elaborating statistical models of the ecology of these biota and in using quantitative predictions derived from these models. Steps to formulating statistical models on the dynamics of populations and assemblages are discussed. Current models are mostly conceptual (~70% of studies surveyed), falling into 2 main classes: population dynamics (including recruitment, mortality, dispersal and availability of patches) and process‐orientated studies (including the response of individuals to the physical environment, biogenic habitat modification, biological interactions and physical perturbations). Most recent studies were descriptive or on the population dynamics of species and were undertaken mostly at spatial scales of up to 1 km and temporal scales of months. The development of statistical models appears to be impeded by the limited scope of studies, an over‐emphasis on conceptual models (but recognizing an important role for a rigorous experiment framework) and a difficulty in using outcomes from small‐scale processes at the level of individual organisms to predict larger scale outcomes where many interactions contribute to variation in abundances. Currently, few studies undertake field assessments of the defining characteristics of habitats, the dynamics of those habitats and the relative importance of different habitats to individual populations. Much urgent work is required to develop large scale (space: > 1 km; time: > 1 years) statistical models. This is because attention needs to be given to those interactions and processes in the ecological systems that will provide for the greatest reduction in uncertainty in the quantitative predictions derived from these models.
What influences the structure of frog assemblages at forest streams?
Authors: Parris Kirsten M. , McCarthy Michael A. 
Published: March 2003

AbstractWe investigated habitat variables influencing the species richness and composition of frog assemblages at forest streams in southeast Queensland, Australia, to (i) determine whether these assemblage attributes can be predicted from the nature of the local habitat, and (ii) assess the value of species richness as a measure of the structure of frog assemblages. Stream size (as measured by the annual volume of precipitation in the upstream catchment) was found to be a significant predictor of the species richness of an assemblage, while stream size, understorey floristics in the riparian zone, the presence of palms and elevation were significantly correlated with the composition of assemblages. No relationship was found between broad forest type and the species richness or composition of frog assemblages. Species richness was not an informative description of the composition of frog assemblages, as assemblages with identical species richness had a low average compositional similarity. Results of this study indicate that frogs are responding to local, ground‐level stream and vegetation variables, a finding of both ecological interest and practical significance for the conservation management of forest‐dwelling frogs.
The effect of flooding and flood timing on leaf litter breakdown rates and nutrient dynamics in a river red gum (Eucalyptus camaldulensis) forest
Authors: Glazebrook Helen S. , Robertson Alistar I. 
Published: March 2003

AbstractComparisons of litter standing‐stocks in low‐lying and higher areas of the floodplain and the effects of controlled flooding events on leaf litter decomposition and leaf litter nutrients were examined during autumn and winter in a southeastern Australian river red gum (Eucalyptus camaldulensis) floodplain forest. The mean mass of total litter and some litter components was significantly greater in autumn than in winter but there were few differences in litter mass between low‐lying flood runners and higher sites (1.5 m) on the floodplain, regardless of season. Leaf decomposition was more rapid in flooded areas than in non‐flooded areas and was significantly faster in autumn than in winter. In flooded leaves, concentrations of phosphorus and nitrogen dropped rapidly during the first 3 days of each experiment, increased to near original after 7–10 weeks and then decreased again. After 112 days of decomposition the C:N:P ratios of leaf litter increased, but this effect was most marked for flooded leaves. Simple models of leaf litter dynamics indicated that leaf litter standing‐stocks in low‐lying flood runners would be reduced by flooding, particularly during autumn. In contrast, models predicted a net gain in standing‐stocks of leaf litter to be higher on the floodplain, particularly in autumn. Alteration to the seasonal timing of floods by river regulation has probably decreased litter standing‐stocks and nutrients available in low‐lying areas of the floodplain to support the production of macrophytes and biofilms during winter and spring floods.
Competition between the larvae of the introduced cane toad Bufo marinus (Anura: Bufonidae) and native anurans from the Darling Downs area of southern Queensland
Authors: Williamson Ian 
Published: March 2003

Abstract Bufo marinus (L) has been present in the northern edge of the Darling River catchment for more than 25 years and the species currently occupies an area north of Chinchilla on the northern Darling Downs. This paper reports on preliminary findings of competition trials between larvae of B. marinus and native anurans in the Darling Downs area. Trials conducted in artificial ponds (1.4 × 1.2 × 0.2 m) indicated that Bufo reduced the growth of three native species (Limnodynastes tasmaniensis (Gunther), Limnodynastes terraereginae (Fry) and Notaden bennetti (Gunther)), and in some trials reduced the survival of two species (L. tasmaniensis and L. terraereginae). A fourth species (Limnodynastes ornatus (Grey)) showed higher growth rates with Bufo resulting from a non‐significant reduction in survival in those treatments. One of two trials conducted in enclosures (1.0 × 0.5 × 0.4 m) placed in a permanent water body indicated that B. marinus had a negative effect on growth of L. tasmaniensis. A survey of 30 breeding sites in the area found that Bufo used only a small number of water bodies in one breeding season and showed little overlap of pool use with most native species. Therefore, although B. marinus may negatively affect growth and survival of native anurans under some circumstances, the potential impact of B. marinus may be minimal if there are always many breeding sites where native anurans can breed in the absence of B. marinus. A more extensive assessment of temporal and spatial overlap of water body use by B. marinus and native anurans is needed to understand the exact impact of B. marinus in this region.
Taxonomic sufficiency in ecological studies of terrestrial invertebrates
Authors: Pik Anthony J. , Oliver Ian , Beattie Andrew J. 
Published: March 2003

AbstractThe concept of taxonomic sufficiency (identifying organisms only to a level of taxonomic resolution sufficient to satisfy the objectives of a study) has received little attention in ecological studies of terrestrial invertebrate assemblages. Here we critically evaluate three approaches to taxonomic sufficiency: the use of morphospecies, genera and functional groups. The objective was to compare estimates of richness (α diversity) and turnover (β diversity) of ant assemblages generated by these data with estimates produced using data for ant species. Ground‐active ants were sampled using pitfall trapping within three habitat types: a eucalypt plantation, woodland regrowth patches and the surrounding grassland at a study site in the upper Hunter Valley, New South Wales. Comparisons of assemblage richness and turnover among taxonomic data sets and habitats and after different data transformations used univariate (simple correlation and ANOVA) and multivariate (Mantel tests,
ANOSIM and
SSHMDS) techniques. Our study found: (i) morphospecies and genus richness was highly correlated with species richness over the study area; (ii) ordination scatterplots using species, morphospecies and genus data revealed similar patterns of site separation for the three habitats; (iii) the results were very similar using untransformed, log transformed and binary data; (iv) functional group ordinations separated all three habitat types for untransformed abundance data; and (v) estimates of species turnover were highly correlated with estimates of morphospecies and genus turnover. These results are discussed in relation to future monitoring of ant community structure.
Selective herbivory by red‐necked pademelon Thylogale thetis at rainforest margins: factors affecting predation rates
Authors: Wahungu Geoffrey M. , Catterall Carla P. , Olsen Mike F. 
Published: March 2003

AbstractWe examined browsing by red‐necked pademelons (Thylogale thetis) on shoots of rainforest plants at areas of rainforest–grassland interface in the Lamington Plateau of southeast Queensland. Terminal shoots from nine species (three each of vines, trees and shrubs) were compared. The effects of five factors (plant species, site, distance from forest edge, habitat (grassland or forest) and time (trip) at two levels of exposure (caged or uncaged)) were also compared. Among the uncaged shoots, 98% showed signs of damage compared with 18% of the caged shoots. In general, shoot predation was higher in the grassland than in the forest and decreased with increasing distance away from the forest edge in both habitats. The three vine species were more heavily browsed than all other species. Browsing by red‐necked pademelons is likely to influence regeneration near forest edges through direct death of seedlings as a result of predation and through altered competitive interactions resulting from selective herbivory. This effect, however, would be lower on seedlings within the forest habitat and would also reduce as seedlings establish themselves further from the forest edge into grassland habitat.
Flowering phenology of myrtaceous trees and their relation to climatic, environmental and disturbance variables in northern New South Wales
Authors: Law B. , Mackowski C. , Schoer L. , Tweedie T. 
Published: March 2003

AbstractPatterns of flowering phenology, which represent a partial description of food availability for nectarivores, are described for 20 species of myrtaceous trees on the mid‐north coast of New South Wales (NSW), Australia. Data were recorded monthly between 1982 and 1992 across 23 sites that comprise a variety of local environmental conditions and disturbance histories. Flowering periodicity and intensity were highly variable between species and sites, ranging from annual flowering to no flowering over the 10‐year period. Cool temperatures prior to floral budding was a strong predictor of flowering for nine species. Extraordinary climatic events also influenced flowering. The period of greatest flowering for all species combined occurred 9 months after the highest monthly rainfall recorded in the survey (March 1985). An 18‐month extreme drought led to poor flowering in Corymbia variegata, Eucalyptus acmenoides, Eucalyptus grandis and Eucalyptus resinifera, but recovery after the drought broke was rapid. In contrast to climate, few site‐based environmental variables explained the intersite variation in flowering performance of the tree species. Site disturbance from logging at two sites during the survey did not influence flowering in the remaining canopy over following years. No species showed a negative correlation with a history of recent logging, and direct comparisons, between large‐ and medium‐sized trees, of the percentage of foliage in flower showed no differences for any species. At the scale of a timber production forest, the negligible effect of tree size (if >10 cm diameter at breast height over bark), and high stem density resulting from selective logging, leave about half of the net harvestable area producing flowers at a similar density to unlogged forest. However, larger trees flowered more frequently than medium‐sized trees in C. variegata (medium: every 5.9 years; large: every 2.3 years) and there was a trend in this direction for 13 of 17 species. Low‐intensity burns and wildfires caused differing amounts of crown scorch, sometimes resulting in bud loss, but most species flowered at prefire levels 1–3 years after the disturbance. Eucalyptus microcorys and Angophora costata flowered poorly at sites that experienced frequent low‐intensity burns. Regionally, blossom shortages occur through a combination of spatial and temporal patchiness in flowering and the clearing of those species that occurred on soils preferred for agriculture. On the north coast of NSW, these shortages commonly occur from late winter to spring. Species that flower reliably in this period include Eucalyptus robusta, Eucalyptus tereticornis and Eucalyptus siderophloia in late winter and E. siderophloia and E. acmenoides in spring.
Coexistence of a locally undifferentiated foraging guild: avian snatchers in a southeastern Australian forest
Authors: MacNally Ralph 
Published: March 2003

AbstractThree species of sexually dichromatic, insectivorous birds (Golden Whistler,Pachycephala pectoralis;Rufous Whistler,Pa. rufiventris;Rose Robin,Petroica rosea) employ a characteristic foraging manoeuvre (snatching or sally‐striking) disproportionately often, leading several studies to group them together in one foraging guild. The three species synchronously co‐occupy an extensive eucalypt forest east of Melbourne, Australia (Olinda State Forest). All assemble in relatively high densities in late winter and through spring and early summer to breed. Log‐linear modelling of use of foraging techniques, substrate, plant species and heights within the forest indicate that all six species–gender groups virtually do not differ from one another: a situation in which very similar species coexist at high densities. The results are considered in the context of interspecific competition among ecologically similar species and it is suggested how such a situation might arise and be sustained. The absence of gender‐specific differentiation within species is also addressed.
Long‐term effects of frequent low‐intensity burning on ant communities in coastal blackbutt forests of southeastern Australia
Authors: York Alan 
Published: March 2003

AbstractPeriodic low‐intensity fire (hazard‐reduction burning) is a conspicuous management strategy in virtually all of Australia’s dry forest communities where it is primarily used to reduce fuel levels with the intention of minimising the extent and severity of wildfires. Little is known, however, about the effects of its repeated use on natural ecosystems over long periods of time. This study investigated the long‐term effects of frequent low‐intensity fire on forest ant communities by comparing frequently burnt sites with long‐unburnt control sites. While the richness of ant communities remained largely unchanged, the composition of assemblages differed substantially between treatments. Although frequent burning apparently resulted in the loss of a substantial number of species, the overall richness of frequently burnt areas was maintained by the addition of species not present on unburnt sites. These changes in species composition were accompanied by major changes in community organisation (structure) and were considered to be a response to altered habitat conditions, particularly litter biomass, vegetation structure and patterns of insolation at ground level. Appropriate fire prescriptions could therefore be applied to manipulate these habitat elements at a landscape scale to meet both management and conservation goals. A comparison of pitfall trapping and litter extraction techniques revealed the importance of a composite sampling strategy, with 22% of ant species detected only by litter extraction.
Evidence for effects of Spartina anglica invasion on benthic macrofauna in Little Swanport estuary, Tasmania
Authors: Hedge Paul , Kriwoken Lorne K. 
Published: March 2003

Abstract Spartina anglica is an exotic perennial grass that can rapidly colonise the intertidal zone of temperate estuaries and lagoons. Consequently, there is considerable concern about its impact on estuarine flora and fauna. This study provides the first investigation of ecological impacts by S. anglica in Australia. The objective was to investigate the impacts of S. anglica on benthic macroinvertebrate communities inhabiting mudflat and native saltmarsh habitats at Little Swanport estuary, Tasmania. The null hypothesis that species richness and species abundance of benthic macroinvertebrates in exotic S. anglica marsh does not differ from adjacent native saltmarsh and mudflat habitats was tested. Eighteen species and 3716 macroinvertebrates were collected from 60 intertidal core samples in three habitats. Species richness, total abundance of invertebrates, crustacean abundance and mollusc abundance of mudflat communities were significantly (P < 0.05) lower when compared to those inhabiting adjacent S. anglica marsh and native saltmarsh. However, species richness and total abundance of invertebrates of native saltmarsh and S. anglica marsh did not differ significantly. Ordination of macroinvertebrate data clearly separated mudflat sites from vegetated sites but showed remarkable similarity between exotic and native vegetated sites.
Distinguishing area and habitat heterogeneity effects: a simulation test of the MacNally and Watson (1997) protocol
Authors: Mcguinness Keith A. 
Published: March 2003

AbstractDistinguishing the roles that different factors, such as sampling effects and habitat heterogeneity, play in generating species‐area curves continues to be difficult in many communities. A recent response to this challenge is the proposal of a ‘zoom’ protocol in which species richness and habitat heterogeneity are sampled in successively larger units (transects or quadrats). The utility of this approach requires that there be justifiable, predictable and unambiguous relationships between richness and heterogeneity. Results of computer simulations that I have done to test the predicted relationships demonstrate, however, that the predicted patterns were not always observed and, on occasion, more complex relationships were observed in their place. While the development of such protocols may increase our understanding of species‐area curves, they are unlikely ever to pronounce unambiguously on their causes.
Foraging ecology of the South Australian glossy black‐cockatoo (Calyptorhynchus lathami halmaturinus)
Authors: Pepper J. W. , Male T. D. , Roberts G. E. 
Published: March 2003

AbstractThe endangered South Australian glossy black‐cockatoo (Calyptorhynchus lathami halmaturinus Mathews 1912) feeds almost exclusively on the seeds of the drooping sheoak (Allocasuarina verticillata), and shows marked preferences for individual trees. This field study investigated foraging ecology and tree selection through observations of foraging birds and measurements of trees and seed cones. The cockatoos spent the vast majority of their foraging time (94%) handling seed cones, and handling behaviour was highly stereotyped. Handling time per cone was correlated primarily with cone size, while seed intake rate was correlated primarily with seed mass per cone. The cockatoos fed mostly in trees with signs of previous feeding. They tended initially to sample trees with large seeds, and to stay for long feeding bouts in trees with high ratios of seed‐to‐cone mass. As a result of these biases, feeding was concentrated in trees with high seed mass per cone. Preferred trees were also larger, with higher ratios of seed‐to‐cone mass and larger seeds containing more lipid and protein. By feeding from selected trees the cockatoos increased both their seed intake rate and the nutritional quality of the seeds ingested, thereby increasing their energy intake rate by an estimated 28%. They did not discriminate against trees that had re‐grown from basal shoots after fires. Insect larvae were present in some seed cones but the cockatoos did not appear to actively seek them. Males foraged 19% more efficiently than females, resulting in greater daily food intake. The characteristics of individual A. verticillata trees that determined the cockatoos’ feeding rates were also correlated with their distribution on a regional scale. This suggests that the distribution of this endangered cockatoo depends not only on the presence of food trees, but also on their regionally varying feeding profitability.