bluuebunny/crossref_metadata_2025_split huggingface dataset:
The feeding ecology of the dingo II. Dietary and numerical relationships with fluctuating prey populations in south‐eastern Australia
Authors: NEWSOME A. E. , CATLING P. C. , CORBETT L. K. 
Published: July 2006

Abstract The dietary and predator‐prey relationships of Canis familiaris dingo were studied for 9 yr at a coastal site and for 1.5 yr at a montane site in south‐eastern Australia. The percentage occurrences of items eaten were obtained from faeces, and the abundances of prey by counting water‐birds, trapping small mammals, and tracking large and medium‐sized mammals on specially prepared soil plots. Dingoes were also estimated by tracking. The diet was broad but predominantly mammalian (23 species). Dietary frequencies were grouped around three weight modes, 0.1, 1.25 and 16 kg, corresponding with bush rat (Rattus fuscipes), ringtail possum (Pseudocheirus peregrinus) and swamp wallaby (Wallabia bicolor). The amplitudes of those frequencies approximately doubled from mode to mode, viz. 4, 13.5 and 28.3%, respectively. Medium‐sized mammals have been recognized as the staple prey because of their dependability. Their density estimates fluctuated least among prey‐groups, and track records of dingoes in the mountains were significantly related to them. Other categories of prey were supplementary (large mammals), opportune (small mammals) and scavenged.Although there were general tendencies for dietary frequencies to follow prey abundances, significant functional and numerical responses were obtained only for water‐birds (coot and swan). Their super‐abundance in the mid‐years of the coastal study and their highly clumped distribution were the likely causes.Predation was disproportionately severe on mammalian prey‐classes after an extensive wildfire at the coastal site. Such predation may have suppressed populations of wallabies and kangaroo for 2 yr until the water‐birds became super‐abundant. The prevalence of wombats in the mountains may have induced heavy predation upon other less numerous large prey. Concepts of profitability in feeding appear to apply to the dingo more than those of optimization of time or energy.The decline in dingoes was correlated most with long‐term declines in water‐birds and medium‐sized mammals. At the time, abundance estimates of wallabies and kangaroos were increasing and those species increasingly predominated in the diet. The ability to hunt co‐operatively was apparently ineffectual in preventing decline in dingo numbers.It is suggested that pack size is related inversely to the level of temporal instability in the environment. Frequent wildfires may prevent staple (mediumsized) and supplementary (large) prey from being abundant simultaneously, a combination thought necessary for large pack size.
Rabbits and the failure of regeneration in Australian arid zone Acacia
Authors: LANGE R. T. , GRAHAM CLARE R. 
Published: July 2006

AbstractThree experiments are reported concerning the effect of rabbit grazing (Oryctolagus cuniculus L.) upon the recruitment of Acacia seedlings to populations in the South Australian arid zone. In western myall woodland (Acacia papyrocaqsa Benth.) under prevailing rabbit and sheep densities, seedlings exposed to grazing by these two herbivores or to rabbits alone were severely pruned, whereas totally protected seedlings grew unchecked. Seedlings of four Acacia species; A. papyrocarpa, A. oswaldii (F. Muell.), A. kempeana (F. Muell.) and A. burkittii (F. Muell. ex Benth.) were transplanted into four 50 m × 50 m rabbit‐proof enclosures. Six rabbits were introduced into each enclosure and within 24 h half of the total seedling population had been grazed. This was at a seedling dry weight ratio of 1|150 000 of the total fodder on offer. In one of the enclosures no seedlings were eaten and there is evidence to suggest that a dense patch of grass had a buffering effect, reducing grazing pressure. Small shoots cut from old Acacia and transferred to the ground throughout 1000 ha of western myall woodland were grazed rapidly near rabbit warrens and progressively less rapidly with increased distance from warrens. The experiments demonstrated that even with the lowered post‐myxomatosis population densities, rabbit grazing pressure would significantly affect recruitment in arid zone Acacia populations in the absence of stock.
Foliage projective covers of overstorey and understorey strata of mature vegetation in Australia
Authors: SPECHT R. L. 
Published: July 2006

AbstractAt maturity, both overstorey and understorey foliage projective covers (FPC) tend to reach steady‐state values which are correlated with the evaporative coefficient (k) in the water balance equation of the soil‐plant‐atmosphere continuum.Overstorey FPCs of mature communities increase linearly from 20 to 85% along the moisture gradient from arid to humid regions. Understorey FPCs in mature communities are relatively constant along the same moisture gradient, increasing only slightly from 40 to 47%.Plant communities which have overstorey FPCs different from the norm, appear to show a compensatory decrease or increase in understorey FPC so that the sum of the FPCs of overstorey and understorey is equal to that predicted for the region.
The epifauna of megaripples: species' adaptations and population responses to disturbance
Authors: SHEPHERD S. A. 
Published: July 2006

AbstractStrong tidal currents flowing over mobile sediment give rise to migrating bedforms termed megaripples and sandwaves. For colonizing epifauna a megaripple field is a habitat subject to repeated disturbance as advancing megaripples bury all epifauna in their path. Eight epifaunal species occur in a megaripple field in tipper Spencer Gulf, South Australia. The stalked bryozoan Lanceopora obliqua is an r‐strategist and occurs patchily in high densities. An ascidian Polycarpa pedunculata, probably a K‐strategist, and a group of four species of articulated bryozoans, have much lower population densities which are predictable according to the frequency of disturbance. Other species occur in low, but variable densities. Some species show adaptations in morphology, behaviour or life history patterns which favour survival in this unusual environment.
Seasonal changes in characteristics of cattle dung as a resource for an insect in southwestern Australia
Authors: MATTHIESSEN J. N. , HAYLES L. 
Published: July 2006

AbstractThe value of cattle dung as a food resource for the bush fly Musca vetustissima (Walker) in the winter rainfall agricultural region of southwestern Australia was assessed by bioassay in the laboratory. The size (headwidth) of adult females was measured from flies reared on different samples of dung. Variation in size correlated with seasonal patterns of pasture growth, larger flies being produced during the growing season from autumn to spring. Size declined with senescence of annual pastures in late spring and early summer, occurring later in southern areas where the growing season was longer. After pasture senescence, dung from shorter growing season areas usually produced larger flies, apparently a result of the inverse relationship between digestibility of feed and length of growing season. Dung from irrigated perennial pastures never produced flies as large as that from annual pastures but generally high values were sustained during summer. Grazing of cereal stubble and feeding of hay in annual pasture areas during summer usually caused some increase in fly size. A spontaneous resurgence in the size of flies often occurred several weeks after pasture senescence and was attributed to more thorough digestion as a result of reduced intake of less palatable dry pasture.
Variation in leaf toughness and phenolic content among five species of Australian rain forest trees
Authors: LOWMAN M. D. , BOX J. D. 
Published: July 2006

AbstractSeveral leaf characteristics, including toughness and total phenols and condensed tannins, were measured in Australian rain forest leaves of different ages and related to observed herbivory rates. In most cases, toughness and chemical toxicity increased as leaves aged, and corresponding insect grazing decreased. Herbivory losses ranged from 4.8% to 32.5% leaf area losses, and were more positively correlated with toughness than with phenolics. It is suggested that a suite of factors, including physical and chemical characteristics of leaves as well as spatial and temporal factors, interact to create variation in grazing intensities.
Effects of urban development and habitat alterations on the distribution and abundance of native and exotic freshwater fish in the Brisbane region, Queensland
Authors: ARTHINGTON A. H. , MILTON DA. , McKAY R. J. 
Published: July 2006

AbstractThe distribution of freshwater fish in creeks throughout the Brisbane region was determined by a survey carried out in 1977–78. Seventeen native and six exotic species were recorded in 55 creeks. Sixteen native and four exotic species were collected in a more restricted survey of central Brisbane in 1981. Urban development and the establishment of exotic plants have resulted in substantial changes to the aquatic environment in many of the creeks surveyed. Exotic grasses, especially para grass (Brachiaria mutica) have reduced the extent of free water by growing partly into stream channels. Floating exotic plants blanketed some stream reaches. Native aquatic macrophytes have declined, apparently due to dredging, siltation and other disturbances. These changes have affected the distribution and abundance of native and exotic fish. Native species with a preference for open water and beds of aquatic plants have declined in creeks overgrown by para grass and floating plants. Melanotaenia fluviatilis, Retropinna semoni, Pseudomugil signifer, Craterocephalus stercusmuscarum and Ambassis nigripinnis have been affected. Para grass and floating plants have not affected the range or abundance of Hypseleotris galii, H. compressus and Mogurnda adspersa. Gambusia affinis and Xiphophorus helleri have been advantaged by expansion of their preferred habitat type ‐ the edges of pools where exotic grasses have grown partly into the water. The effect of exotic fish on native species is unclear. There was a correlation between large numbers of G. affinis and small numbers of H. galii and M. fluviatilis. Correlations could result from predatory or competitive interactions between species. Alternatively, correlations could be due entirely to the effects of habitat alterations on exotic and native species. However, H. galii was evidently not disadvantaged by the habitat alterations studied. Thus there may be a complex interaction between this species and G. affinis. There was no evidence that X. helleri had affected the range or abundance of native species.
Species diversity and temporal distribution of ants in the semi‐arid mallee region of northwestern Victoria
Authors: ANDERSEN ALAN N. 
Published: July 2006

AbstractThe ant communities of two adjacent sites bearing markedly different vegetation (heath and mallee) were studied using quadrat counts and pitfall traps in semi‐arid northwestern Victoria. The ants were extremely abundant and rich in species (86 species from 27 genera were recorded from two 50 m × 25 m plots within 25 m of each other) and were dominated by species ofMonomorium and Iridomyrmex. Pronounced site differences in species composition were found, with 73% of the most abundant species showing a strong site preference. The ants exhibited marked seasonality: activity was highest in summer and lowest in winter and this was accompanied by a high turnover of species in time, resulting in pronounced seasonal differences in species composition. Most foraging was nocturnal during summer but was almost exclusively diurnal during winter, and individual species displayed distinctive patterns of diet foraging activity. Although the overall temporal distribution of the communities were apparently controlled by temperature, interspecific competition may also be an important factor influencing the seasonal and diel distributions of individual species, resulting in their high degree of temporal separation. The overall consequence is that although the study area contains many abundant species with similar ecological requirements, few of these are active in the same place at the same time.
Estimates of damage by herbivorous insects onEucalyptustrees
Authors: FOX L. R. , MORROW P. A. 
Published: July 2006

AbstractHigh levels of insect damage on Eucalyptus have been noted but not quantified in previous literature. We present estimates of leaf damage for 44 Eucalyptus species from a variety of habitats. Overall, an average of 15% of expanded leaf area was missing. While some species were generally lightly grazed, others, especially those in more mesic. higher altitude communities, usually sustained much heavier leaf damage. In the age and size classes, communities and years that we sampled, the overall levels of damage to eucalypts were higher than chronic damage levels reported for north temperate communities. We also suggest a simple method for rapidly estimating the proportion of leaf area missing from trees.
Altitudinal distribution of several eucalypt species in relation to other environmental factors in southern New South Wales
Authors: AUSTIN M. P. , CUNNINGHAM R. B. , GOOD R. B. 
Published: July 2006

AbstractFour problems associated with studying the altitudinal distribution of eucalypt species are examined: the lack of specific physiological relationship between altitude and plant growth, the influence of other environmental factors, the availability of suitable data and the need for statistical analysis. Presence/absence data for eucalypt species were obtained from several sources. Probability of occurrence in 100 m zones is determined for E. maculata, E. muellerana, E. fastigata, E. sieberi, E. dalrympleana and E. pauciflora. The influence of other factors is demonstrated for several species using direct gradient analysis. Aspect is important for E. fastigata and E. rossii in addition to altitude and rainfall.The statisical model used was the logit‐linear model: log (p/I– p) = linear function of environmental variables where p is the expected probability of being present for a given combination of environmental variables. Two examples are presented. E. dalrympleana can be predicted from altitude, rainfall, radiation index (measure of aspect) and an interaction term between altitude and aspect. E. rossii presence is predicted by altitude, rainfall, radiation index and geology. Altitude is transformed into an estimate of mean annual temperature which is shown to clarify some overlaps of species distribution.It is concluded that use of data collected for other purposes can be used in a generalized linear model for presence data to show the complex correlations which exist between the altitudinal distribution of some eucalypts and other environmental factors.
Scale problem in classification: an application of a stochastic method to evaluate the relative homogeneity of sample units
Authors: DALE P. E. R. 
Published: July 2006

AbstractA basic problem in experimental design is to select a sample unit at a scale appropriate to the variables being observed and to the nature of the topic. Where hierarchical classification procedures are used it is important that the scale of the basic units is such that any variation found within the sample is small relative to that between the groups formed. In this paper a method is applied to evaluate the relative homogeneity of sample units. Replicates from each sample are classified hierarchically. The method of Sandland & Young (1979a, b) is used to determine the probability at division of the number of replicates assigned at a division to the same group occurring by chance. A high probability indicates relative heterogeneity of the samples from which replicates are drawn; a low probability suggests relative homogeneity. An example from the area of urban ecology illustrates an application of the method. It is used to evaluate the relative homogeneity of spatial units (Census Collectors Districts) with respect to dwelling characteristics in inner city Brisbane. Possible applications in other areas of ecology are briefly considered.
Banksia ericifolia transgresses the self‐thinning boundary
Authors: MORRIS E. C , MYERSCOUGH P. J. 
Published: July 2006

AbstractSelf‐thinning B. ericifolia stands were observed to have high mean plant weights for their density, exceeding the upper boundary of the (log mean plant weight = 4.4–1.5 log mean plant density) line of White (1980) by approximately 0.5 units on the y scale (log mean weight per plant (g)). While proportion of shoot as stem and leaf area indices were similar in thinning stands of B. ericifolia and other species, specific leaf area was six to eight times less in the Banksia populations.
Short note Report of diurnal acid metabolism in two aquatic Australian species of Isoetes
Authors: KEELEY JON E. 
Published: July 2006

AbstractPrevious studies have demonstrated the presence of crassulacean acid metabolism in the North American submerged aquatic Isoetes howellii (Isoetaceae). Diurnal changes in titratable acidity and malic acid levels indicate the presence of this pathway in two Australian species of Isoetes.
Changes in Melaleuca forest density on the Magela floodplain, Northern Territory, between 1950 and 1975
Authors: WILLIAMS ALEXANDER R. 
Published: July 2006

AbstractThe stability of the Magela floodplain prior to the development of uranium mining at Ranger, in the Magela catchment, was estimated by comparing aerial photographs taken in 1950 and 1975, using the density of Melaleuca swamp forest as an index of change. The 1975 photographs were interpreted in the light of a ground survey carried out in the dry season of 1976. There was no increase in the area occupied by Melaleuca trees, indicating that infilling of perennial swamp and plant succession were not significant agents of change in this period. Thirty‐eight per cent of the forested area suffered a significant decrease in tree density: fire, wind and buffalo are among the probable causes, and these hazards should be taken into account in monitoring the effects of the uranium mining.
Altitudinal variation in Leptospermum flavescens Sm. (Myrtaceae)
Authors: MORRISON DAVID A. 
Published: July 2006

AbstractCorrelation of altitude with morphological data from herbarium specimens of two taxa within the Leptospermum flavescens group indicates that, in the Sydney region, there is a convergence of leaf and flower size at higher altitudes. There are also altitudinal differences in germination ability, growth rate and leaf chemistry. Experimental evidence suggests that at least some of this altitudinal variation is genetically fixed within the populations.
Experimental confirmation of interspecific competition between native and introduced mice
Authors: FOX BARRY J. , POPLE ANTHONY R. 
Published: July 2006

AbstractThis paper tests the hypothesis that Pseudomys novaehollandiae shows competitive superiority over Mus musculus. Experimental removals of P. novaehollandiae on four I ha treatment plots and additions on a further four I ha plots show significant effects of interspecific competition when compared to two I ha unmanipulated control plots. Significant effects of P. novachollandiae populations on the abundance of M. musculus populations were observed for number of captures/day, abundance/trapping session and for the recruitment of new individuals over the post‐removal period, thus allowing rejection of the null hypothesis in each case. There was an apparent ceiling on the total rodent abundance which is indicative of a resource limitation. The resource in short supply appears to be space, but it is not clear if the competition is for food or shelter resources contained within such space or for the space per se, but the latter seems less likely.The confirmation of this interspecific competition supports the inferences drawn from a considerable amount of indirect evidence, largely descriptive, obtained from previous studies in the Myall Lakes National Park. This study also shows that competition is one of the mechanisms controlling the replacement of species in the succession following disturbance and lends support to the habitat accommodation model proposed for such succession. These points support previous statements on the importance of interspecific competition as a determinant of the structure of these small‐mammal communities.
Nectar utilization and pollination by Australian honeyeaters and insects visitingCalothamnus quadrifidus(Myrtaceae)
Authors: COLLINS BRIAN G. , NEWLAND CHARLES , BRIFFA PETER 
Published: July 2006

AbstractNectar availability inCalothamnus quadrifidusflowers was studied at Wongamine Nature Reserve in late spring (November). Despite some overnight depletion by moths and other invertebrates, more nectar was present in flowers at dawn than at the preceding dusk. Significant nectar depletion occurred within a few hours after dawn, mainly due to foraging by two honeyeater species.Lichmera indistinctaandPhylidonyris nigra. Thereafter, nectar availability was maintained at relatively low levels, principally because of foraging by honeyeaters and honey bees.Apis mellifera, that became active during the warmer part of the day. Although individual honeyeaters consumed more nectar than A.mellifera, honey bees were so abundant that their total impact was greater than that of either honeyeater species for much of the day. Transfer ofC. quadrifiduspollen between flowers is necessary in order to achieve a high level of seed set, as the flowers appear to be protandrous. Honeyeaters appeared to be considerably more significant pollen vectors thanA. mellifera.
Effects of fire on central Australian rangelands. I Fire and fuel characteristics and changes in herbage and nutrients
Authors: GRIFFIN G. F , FRIEDEL M. H. 
Published: July 2006

AbstractResults of fire experiments in two important rangeland types in central Australia showed that a winter fire was effective in reducing fuel and was easily controlled. Composition of pasture plants palatable to cattle was either maintained or improved. A summer fire significantly decreased the grass component white increasing the proportion of forbs, particularly unpalatable species. Rainfall, season of burning and reduction of cover appeared to be important factors in controlling the composition of post‐fire herbage. There was no important effect of fire on nutrients in either season of burning.
The influence of intensive sheep grazing on genotypic differentiation in Danthonia linkii, D. richardsonii and D. racemosa on the New England Tablelands
Authors: SCOTT A. W. , WHALLEY R. D. B. 
Published: July 2006

AbstractGenotypic differentiation studies involving three native pasture grasses Danthonia linkii Kunth, D. richardsonii Cashmore and D. racemosa R.Br. were made, using populations both collected from the field and grown from selfed seed, to investigate the influence of the intensive grazing and high soil fertility associated with sheep camps on a number of morphological and developmental characters. Each species was represented by at least a pair of populations one of which was sampled from a sheep campsite, the other(s) from an adjacent site as close as possible to the camp but outside its influence.The sheep camp populations were generally more prostrate with shorter tillers, greater tiller numbers, later flowering time, and in one population group, a larger number of seeds set. These differences were more apparent in the parent populations collected from the field but grown under uniform conditions than in the F1 populations produced from selfed seed.These population differences were interpreted as representing genotypic differentiation produced by intensive selection pressures introduced since the development of the sheep camps. They were certainly more intensive in populations drawn from sheep camps which had been in existence for a longer time. The selection pressures which produced the new populations also appeared to maintain a broad base of genetic variability rather than result in populations more uniform than the original.