bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tasmanian high altitude grassy vegetation: its distribution, community composition and conservation status
Authors: KIRKPATRICK J. B. , DUNCAN F. 
Published: July 2006

AbstractGrassy woodland, grassy shrubland, grassy sedgeland, tussock grassland and grassland are extensive on basalt, limestone and fine‐textured Quaternary deposits, are occasional on dolerite, granite and fine‐grained sedimentary rocks, but are absent from the siliceous mountains of Tasmania. With the exception of limestone lithosols, the grassy communities are confined to relatively deep soils with a low surface rock cover. Much of the area of the grassy communities below the climatic treeline has clearly been forest in the recent past, although some of the higher subalpine plains seem likely to have been grassy at least since the peak of the Last Glacial. The first axis of an ordination of floristic data from 190 quadrats had at one extreme the grassy communities which most resembled in their species composition the sedgelands and sclerophyll shrub woodlands of the west of Tasmania, and at the other extreme the grassy woodlands on relatively fertile, well drained sites in the centre and east of Tasmania. The second axis was correlated with altitude, probably inversely reflecting the growing season. The third axis was related most closely to a soil drainage index. Many of the 15 communities recognized from a polythetic divisive classification of the quadrats have highly local distributions. Six of the communities are totally unreserved and four are poorly reserved. An iterative method is used to develop a minimum reservation strategy involving seven areas.
The occurrence and diet of fishes in a tidal inlet to a saltmarsh in southern Moreton Bay, Queensland
Authors: MORTON R. M. , POLLOCK B. R. , BEUMER J. P. 
Published: July 2006

AbstractThe fishes occurring in the main tidal inlet to a typical saltmarsh situated in southern Moreton Bay were studied from January to December 1984. The aim of the study was to determine the type of fishes and their feeding habits within the inlet, particularly for species of economic importance. Sampling was conducted at night on the full and new moon phases, and during the day on the full moon phase. A total of 19 species were recorded from the inlet, of which 11 are of economic importance. Six species were considered common. Most fish which entered the inlet were juveniles. The diversity of the fish assemblage from the inlet was low when compared with findings of other studies conducted in Australian subtidal mangrove areas. Diel differences in the sire offish entering the inlet were recorded for several species. Two mark‐recapture programmes were conducted to investigate short‐term utilization of the saltmarsh by fishes. Recapture rates indicated that individuals of some species regularly utilized the saltmarsh. The most abundant species from the inlet were predominantly benthic feeders although one species fed on plankton. Terrestrial foods formed an important part of the diet of some fishes. The inlet serves as a feeding area for certain species although it is unlikely that these species rely exclusively upon the area. Future management of saltmarsh areas should include protection and maintenance of tidal inlets wherever possible.
The ecology of Salmonella serotypes in a wild marsupial (the quokka Setonix brachyurus) in a disturbed environment
Authors: HART R. P. , IVESON J. B. , BRADSHAW S. D. 
Published: July 2006

Abstract Previous studies have shown that the quokka (Setonix brachyurus: Marsupialia) experiences a very extensive proliferation of Salmonella infections on Rottnest Is. (Western Australia) in association with seasonal starvation in a disturbed environment. The study reported here examined the distribution of the serotypes involved, the interaction of Salmonella with other hosts, and the resulting environmental contamination. In the quokka, the serotypes were found to be significantly non‐random in their distribution between areas (regardless of a seasonal cycle of infection rate in some areas) and between seasons. No one serotype showed a particular affinity for the quokka in the most adverse season. Study of the largest deviations showed that they could have been due to local amplification of particular serotypes in other hosts. It was not generally possible to distinguish the native and exotic serotypes as groups, and each serotype needed to be studied in terms of its own ecology. Environmental contamination is extensive due to proliferation of Salmonella in quokkas, but the interactions with other hosts were found to be important in determining the local distribution of serotypes. The results of this study are discussed in terms of the significance of the distribution of Salmonella in natural and disturbed areas in Western Australia, and of management of the problems created by proliferation of Salmonella in the Rottnest Is. quokka.
Effects of salinity and waterlogging on the vegetation of Lake Toolibin, Western Australia
Authors: FROEND RAYMOND H. , HEDDLE ELIZABETH M. , BELL DAVID T. , McCOMB ARTHUR J. 
Published: July 2006

AbstractIncreased rates of tree senescence and mortality in and adjacent to an ephemeral lake in the Western Australian wheatbelt have been attributed to increased levels of soil salinity and inundation following agricultural clearing. Winter lake salinities approximate freshwater lake values, but during periods when the lake is dry, capillary rise of groundwater is thought to increase surface soil salinity. An undescribed species of Melaleuca and Casuarina obesa dominated the seasonally inundated regions of the lake bed. Aeolian deposits of higher elevation were dominated by Eucalyptus loxophleba, Allocasuarina huegeliana or species of Banksia. Woodland of E. oleosa var. longicornis and E. salmonophloia occurred predominantly on upland fluviatile deposits of sand and sandy clays. Measurements of soil salinity and the calculation of percentage inundation from tree elevations and observations of tree vigour and xylem pressure potential response indicated that tree deaths in Melaleuca sp. and C. obesa were due to increased levels of salinity. Deaths and low vigours in E. rudis were attributed to both increasing salinities and prolonged inundation. We believe control of ground water levels should be a major consideration in the preservation of this ephemeral lake and the water fowl populations it supports.
Spatial heterogeneity of post‐dispersal survivorship of Queensland rainforest seeds
Authors: WILLSON MARY F. 
Published: July 2006

AbstractShort‐term seed survivorship for several species of the Queensland rainforest was compared in forests and early successional fields, treefall gaps and forest interior, and an array of microhabitats (tree buttresses, logs, forest floor with and without leaf litter cover). Seed survivorship was lower in forest than in field at one site, but equal at another. No differences were found in and out of treefall gaps, in contrast to several other studies. Microsites had little consistent influence on short‐term seed survivorship. A survey of the literature showed no consistent habitat or microhabitat patterns in seed survivorship.
Survivorship, growth and self‐thinning in Banksia ericifolia
Authors: MORRIS E. C. , MYERSCOUGH P. J. 
Published: July 2006

AbstractHigh‐density (dense) and low‐density (sparse) plots were set up in naturally sown monospecific stands of Banksia ericifolia in coastal heath, 3 years after fire. This was done both in high‐growth and low‐growth areas. Plant mortality was recorded quarterly, and two harvests were made at 6 and 9 years to sample growth. Density‐independent mortality at an exponential rate was observed in the low‐growth treatments at both densities, and in the high‐growth sparse treatment. Growth level affected mortality, with the half‐life of populations in the high‐growth sparse plots being double that of populations in the low‐growth plots. Density‐dependent mortality (self‐thinning) was seen only in the high‐growth dense plots. Seasonal effects on mortality were slight; maximum mortality was observed in the spring‐summer period in plots subject to density‐independent mortality, and in the winter‐spring quarter in plots that had self‐thinned. Yields in the high‐growth plots and the low‐growth dense plots were high for heath vegetation. The self‐thinning populations did not exceed White's (1985) upper boundary for thinning lines of log intercept (K) = 5 on standardized axes. The data suggested a log intercept value in the range 4.8–4.9 in the high‐growth stands assuming a thinning‐line slope of – 1.5. Banksia ericifolia (a large shrub/small tree) has a high mean plant weight per given thinning density compared with trees, where an upper limit of log K= .4 has been suggested by White (1985). The volume of canopy space per plant in B. ericifolia is not unusual compared with other species. The amount of biomass packed into a given volume of canopy space was high in this Banksia, achieved by having leaves with a low ratio of area to weight (specific leaf area, SLA). For given values of density, leaf area index and proportion of shoot as leaf, plants with a low SLA will be several times heavier than plants with a high SLA. This achieves a high biomass to volume ratio without an erectophile canopy and may explain the high intercept seen for thinning lines of conifers.
Factors determining seed persistence of Chondrilla juncea L. (skeleton weed) in southern Western Australia
Authors: PANETTA F. D. 
Published: July 2006

AbstractExcept when sown into non‐wetting soils, buried seeds (achenes) of Chondrilla juncea germinated readily following summer rainfall events of less than 10 mm. Seeds lying on the surface were much less likely to germinate in response to small rainfall events, but were prone to predation by seed‐harvesting ants. Although seedlings were capable of resuming growth following temporary dehydration at the earliest stages of emergence from the pericarp, very few of these were able to establish. Establishment from summer germination was virtually nil.The capacity to germinate at higher temperatures was increased following storage for seeds which had been produced in February and March. However, this was considered to be only a weak expression of a release from relative dormancy, compared to the marked changes in temperature response which occur during the after‐ripening of many winter annuals. Differences in the germination behaviour and persistence of seeds of the narrow‐leafed and broad‐leafed forms of C. juncea, when evident, were usually slight.On the basis of an analysis of climatic records for 13 wheatbelt sites, obtained over the period for which C. juncea has been known to occur in Western Australia, it is argued that more than two germinating events could be expected to occur, on average, during the summer months. The relative absence of mechanisms which might confer protection from the effects of unseasonal rainfall, in conjunction with evidence for high levels of seed predation, point to considerable seed losses. Thus the abundance of the species elsewhere in Australia appears to have resulted from its capacity for vegetative regeneration.
Early Holocene population expansion of some rainforest trees at Lake Barrine basin, Queensland
Authors: CHEN YINSHUO 
Published: July 2006

AbstractPollen influx data derived from a sediment core from a small crater lake were related to two population growth models. Doubling times for some tropical rainforest tree taxa, estimated from the models, are 63–165 years for angiosperms and 199–355 years for conifers. These values are generally higher than those for temperate forest trees in the Northern Hemisphere. The results show that fossil pollen data can provide useful information on tree population ecology in tropical areas.
The impact of predation by the powerful owl, Ninox strenua, on a population of the greater glider, Petauroides volans
Authors: KAVANAGH RODNEY P. 
Published: July 2006

AbstractPowerful owls were frequently observed during a study of the ecology of a community of arboreal marsupials in south‐eastern New South Wales. For about 17 months the population of greater gliders in the 100 ha study area appeared to remain ‘stable’ at more than 80 individuals. In the following 46 months, the population declined to about one‐tenth of its previous level. The forest in the study area was unlogged and remained undisturbed during this period. The frequency of sightings of powerful owls holding captured greater gliders, and of observations on the ground of tails and bodies belonging to greater gliders, and the unaccountable disappearance of 9 out of 11 individually marked greater gliders in the study area, suggest that the observed decline in the population of greater gliders was due to predation by the powerful owl. Powerful owls were not detected in the study area during the first 12 months or the last 21 months of the study. It is suggested that powerful owls forage by concentrating their activities in pockets of their large home range until they reduce the populations of their preferred prey below limits where it becomes difficult to catch the remaining animals. If preferred prey are available elsewhere, powerful owls probably move their centres of foraging activity to these pockets and harvest them before moving on to the next pocket of their range.
Behavioural mechanisms of microhabitat selection and competition among three species of arid zone dasyurid marsupial
Authors: MOSS G. L. , CROFT D. B. 
Published: July 2006

AbstractBehavioural mechanisms that may facilitate ground surface microhabitat separation of the Australian arid zone dasyurids, Sminthopsis crassicaudata, Planigale gilesi and P. tenuirostris, were investigated in a terrarium under conditions identical to summer and winter conditions. Controlled introduction and removal experiments showed that in the presence of S. crassicaudata on the ground surface, both P. gilesi and P. tenuirostris exhibit changes in their general behaviour along with an absence of surface activity and a significant decrease in the percentage of total time spent active. This is accompanied by an increase in the frequency of active bouts less than 30 s in duration and a decrease in the frequency of bouts of greater than 30 s duration. These results suggested avoidance of S. crassicaudata at the surface by the planigales, and that behavioural interference could be a mechanism maintaining the spatial and temporal use of microhabitat of these carnivorous species. This study supports much of the indirect evidence suggesting that interspecific competition is an important factor influencing the structure of dasyurid communities.
Yearly variation in seasonal patterns of honeyeater abundance, flower density and nectar production in heathland near Sydney
Authors: PYKE GRAHAM H. 
Published: July 2006

AbstractDespite a consistent seasonal pattern of daily production of nectar‐energy per unit area with peak production around the end of May, the seasonal pattern of honeyeater abundance is not consistent between years and does not correspond to the pattern of nectar‐energy production.
The impact on native mammals of land‐use changes and exotic species in the Bega district, New South Wales, since settlement
Authors: LUNNEY DANIEL , LEARY TANYA 
Published: July 2006

AbstractHistorical records for the Bega district were examined to chart the environmental changes wrought by Europeans through habitat alteration and the introduction of exotic species, and to interpret the impact of these on native mammals. Early recorded increases in native mammal populations, particularly koalas, may have been attributable to a decline in Aboriginal hunting pressure. After settlement in 1830, the valley forest was cleared progressively, ecosystems were altered by grazing and improved pastures, and many introduced plants became weeds in the disturbed environment. The timber industry exploited the forests of the valley and then the slopes of the surrounding mountains. Three exotic mammal species had a major impact on the district — hares, rabbits and foxes. Of the native fauna, the large and medium sized mammal species were those recorded most frequently. Dramatic fluctuations in numbers occurred in most of these species, and many reached plague proportions between 1880 and 1910, after which their numbers fell sharply. The peaks of exotic mammals and the decline of native mammals coincided with the clearing of the remaining forests in the Bega Valley. Many native mammal species are now rare, four are in danger of extinction, and at least six species have become locally extinct since settlement. As most of the native mammal populations in the district now occur in the State Forests surrounding the Bega Valley, the importance of preserving or managing these forests for wildlife must be weighed against proposals to manage the forests for pulpwood (woodchip) production.
Spatial patterning of sweet briar(Rosa rubiginosa)by two vertebrate species
Authors: HATTON THOMAS J. 
Published: July 2006

AbstractThe dispersal and spatial patterning of sweet briar(Rosa rubiginosa)by pied currawongs(Strepera graculina)and horses(Equus caballus)on the southern tablelands of New South Wales was investigated. These two vertebrate species eat the sweet briar fruits and disperse them in a viable condition. The spatial patterns of horse faeces and pied currawong pellets were shown to correspond to the patterns of sweet briar in paddocks which had one of these vertebrate species present. Paddocks with a history of horse grazing but with no large roosting trees had sweet briar populations which were distributed almost randomly; in paddocks never grazed by horses but with roosting trees there was a strong aggregation of sweet briar under trees. These spatial patterns were additive in paddocks with a history of both horse grazing and large trees. Such structuring of vegetation by vertebrates is discussed as an alternative hypothesis to be considered when interpreting ecological processes from spatial patterns.
Colonization of experimentally disturbed patches by stream macroinvertebrates in the Acheron River, Victoria
Authors: DOEG T. J. , LAKE P. S. , MARCHANT R. 
Published: July 2006

AbstractTwenty‐five patches (1 m2) of natural stream substratum in the Acheron River, Victoria, were physically disturbed by kicking and raking during winter 1986 and summer 1987. The macroinvertebrate composition of these disturbed patches was examined at various times over the following 71 days, and compared with adjacent undisturbed control patches sampled concurrently.The disturbance did not alter the particle‐size distribution (> 150 μm) of the disturbed patches. Organic material was reduced in the disturbed patches by about 70% in each season, but returned to control levels within 21 days in winter and 8 days in summer.The total number of species, and the density of species and individuals were all significantly reduced by the disturbance. Recovery of species density was complete after 21 days during winter and 8 days during summer, and the density of individuals recovered after 71 days during winter and 8 days during summer. The differences were due to the slower colonization rate of Chironomidae in winter, either because of a lower drift rate, or a slower recovery of detritus in winter.Individual species showed variations in colonization patterns, most increasing steadily at various rates, with some declining after an initial rapid increase (e.g. Baetis pp.). In the latter case, the density changes were mirrored in the control patches, emphasizing the need to take control samples concurrently with experimental samples.In each season, the species remaining immediately following the disturbance, and those subsequently colonizing the disturbed patches were in the same rank order (Spearman Rank correlation) as their occurrence in the control patches, suggesting that no taxa were differentially affected by the treatment.No evidence was found to allow the application of the Intermediate Disturbance Hypothesis to explain species diversity at the scale of this study. It appears that current hypotheses developed to explain the relationship between diversity and disturbance in sessile communities do not apply to highly mobile communities in streams.
Post‐dispersal seed predation of an exotic weed, Mimosa pigra L., in the Northern Territory
Authors: WILSON C. G. 
Published: July 2006

AbstractThe removal of seeds of the exotic shrub Mimosa pigra from the ground beneath a thicket of the plant and from the open floodplain surrounding the thicket was studied experimentally. Seeds placed beneath the canopy of the M. pigra thicket were taken predominantly by vertebrates (probably omnivorous rodents) while those on the open floodplain were taken predominantly by ants. After 14 days exposure with no barriers to seed removal, less than half of the seeds placed in either habitat had disappeared. Of the seeds that were removed, over 75% had disappeared from both habitats within 5 days. It is unlikely that post‐dispersal seed predation appreciably inhibits the spread or maintenance of stands of this weed in tropical Australia.
Predation by Australian magpies (Gymnorhina tibicen) on pasture invertebrates: Are non‐territorial birds less successful?
Authors: VELTMAN CLARE J. , HICKSON ROBERT E. 
Published: July 2006

AbstractDiet composition and prey intake rates of Australian magpies in a New Zealand population were investigated to determine whether flocking, non‐territorial birds were less successful predators of pasture invertebrates than territorial birds. Time‐activity budgets showed that flock magpies foraged throughout the day during February and March, indicative of a prey shortage at that time. Prey abundance was therefore measured in the autumn months but there was no evidence of a large quantitative difference in the food supply of flock and territorial magpies. Significantly fewer invertebrates were collected from pitfall traps in the flock foraging area, but these were counterbalanced by significantly more scarab beetle larvae and more flying insects, obtained by sweep‐netting. When compared with territorial magpies, flock birds exhibited similar peck rates, prey intake rates, and earthworm intake rates. While there were qualitative differences in the diets of flock and territorial magpies, determined by faecal analysis, five of seven prey items analysed were captured in the same relative proportions by the flock and territorial birds. Earthworms exceeded their relative availability in the diets of flock birds, and more scarab larvae were found in the diets of territorial magpies. Non‐territorial magpies were therefore no less successful than territorial birds during the autumn, and it is suggested that the function of flocking behaviour may eventually be discovered through consideration of why non‐territorial birds never occur as solitary individuals, rather than emphasizing comparisons with territorial magpies.
The effect of water temperature on the functional response of the water stick insect Ranatra dispar (Heteroptera: Nepidae)
Authors: BAILEY P. C. E. 
Published: July 2006

AbstractFunctional response curves were constructed for adult Ranatra dispar feeding on four different densities of notonectid prey at 15, 20, 25 and 30°C. Values for the attack‐rate and handling time were estimated from Roger's random predator equation. The most generally applicable response was the type II, with the mean number of prey eaten increasing with increase in temperature. The attack‐rate was linearly related to temperature while handling time decreased exponentially with increase in temperature, although values changed very little between 20 and 30°C. It is suggested that changes in metabolic activity and related ‘hunger’ effects on various components of predatory behaviour account for the observed number of prey eaten up to 25°C, however, an increase in the level of prey activity at 30°C may influence the observed number of prey caught (and eaten) at this higher temperature.