摘要:

AbstractMany species of honeyeaters and other nectar‐feeding birds occur in most habitats in South Australia. They frequently feed on nectar of the same species of plants. A succession of species of plants provide nectar for birds throughout the year. Nectar is most abundant in winter and early spring and least abundant in summer and autumn. There is more nectar per flower and more flowers in winter and spring. Nectar is often depleted by honeyeaters, and sometimes other visitors (silvereyes, lorikeets and insects) between December and May. It is at times reduced to a level at which it is uneconomical for some species to exploit. There are seasonal movements of honeyeaters into areas of abundant nectar and out of these areas when nectar becomes scarce. Breeding coincides with peak abundance of nectar.Diversity of honeyeaters is probably maintained by an interaction of two types of competition, exploitation and interference. The larger species use the richest sources of nectar and aggressively exclude the smaller species (interference) whereas the smaller species can use poorer sources of nectar because their energy requirements are less (exploitation

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01205.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractA small vertebrate community of eighteen terrestrial species was revealed by removal trapping in 1 ha of Western AustralianBanksiawoodland in autumn. Nine of these species were lizards, three were mammals, three were snakes and three were frogs. The use of pitfall and mammal traps on an 8 × 8 m grid was shown to be sufficient to census the majority of terrestrial species in the study site. A biomass of 2063 g/ha of terrestrial species was estimated from trapping records. Frogs (three species) had the greatest biomass (41% of total), but the introduced mouse Musmusculus contributed the greatest biomass (36%) of any single specie

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01206.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractFeeding in the platypus(Ornithorhynchus anatinus)was investigated by identifying material found in the cheek pouches of animals trapped in nets in a study area on the upper Shoalhaven River, N.S.W. Benthic samples were taken in the rapids and pools of the river and the relative abundance of food items available was related to the food found in the platypus cheek pouches.The main food organisms found were insect larvae, notably Trichoptera, Diptera, Coleoptera, Ephemeroptera and Odonata. Subsidiary food items found included freshwater shrimp(Paratya australiensis), bivalve mollusks(Sphaeriumsp.) and one anuran. The main food items were generally taken in direct proportion to their numerical abundance in the river. Comparisons are made with the food selected by the brown trout(Salmotrutta)from the area.Estimates are made of the weights of invertebrate food necessary to maintain a platypus in various seasonal conditions.

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01207.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractMortality factors and life‐history strategy central to the population dynamics of a common Australian mud‐daubing waspSceliphron laetumhave been determined by the examination of remains left behind in mud nests. A life table has been constructed for the species and details of its life cycle, parasites and predators are presented. Results suggest that the effort involved in nest construction is rewarded by a very low egg, larval and pupal mortality, and that the population size may be limited by a shortage of suitable nesting si

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01208.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractA nuclear polyhedrosis virus (NPV) was found to be widespread throughout the distribution of the light‐brown apple moth (LBAM),Epiphyas postvittana(Walker), in southeastern Australia.Tests were done on sample cohorts drawn from laboratory strains and field populations to determine whether (i)susceptibility to NPV varied significantly in LBAM; and (ii) responses which exposure to the virus was known to elicit in the CAN Laboratory Strain (Geier&Oswald 1977) could be regarded as typical of the species.It was shown that discrete breeding groups could differ greatly in the relative mortality which they sustained following similar exposures to NPV. Whereas more females died than males in all virus‐treated cohorts, as had been previously established in the CAN Strain, the demographic impairment typical of many individuals surviving exposure to NPV in that very tolerant strain (reduced weight of females, reduced fecundity and fertility) was not generally manifest in more susceptible forms of the species.Field surveys so far have not been detailed enough to reveal distribution patterns in the host‐pathogen relationship. The epidemiology of the virus is unknown and its role in the life system of LBAM is not under

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01209.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractIn the northern dry sclerophyll jarrah(Eucalyptus marginataSm.)forests of South‐west of Western Australia abundant germination of soil‐stored seed of leguminous species commonly occurs following wildfire. Broad scale regeneration of legumes does not occur following normal low to moderate intensity prescription burning. Regeneration of leguminous species has been achieved on several sites by high intensity prescription burning without significant damage to the boles of crop trees.Leguminous seed is redistributed both vertically and horizontally by ants following seed‐fall. The bulk of the seed occurs at depths at which there is no heat pre‐treatment during normal prescription burns.Promotion of native legume species by modification of prescription burning techniques could be used to improve the health of the

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01210.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractLitter accumulation dynamics and first year rates of disappearance were investigated for leaves of overstorey and understorey species in the mixed eucalypt forest in the Griffith University study area, Queensland, Australia.The average biomass of the litter layer, was 10.2 t/ha. The wood and overstorey leaf litter formed 62.7% of the accumulated litter biomass, and were spread continuously across the ground. The distribution of shrub litter was discontinuous, being concentrated in localized patches beneath individual plants.The litter bag and tethered leaf techniques were used to measure the rate of disappearance of overstorey and shrub leaves. The ‘pairedquadrat’ technique was used to measure the weight loss of the grasses. The small leaves of the dominant shrub,Pultenaea villosaWilld. disappeared most rapidly, followed by the overstorey leaves, grasses and Acacia leaves. Fragmentation by physical factors and litter fauna appeared to be the major factors responsible for the disappearance of the overstorey leaves during the first year of exposure. The data suggest that removal of leaf constituents by leaching and microbial decomposition were more important for the shrub litter than the overstorey leaves.Fractional disappearance rates (loss constants) obtained from the short term weight loss measurements, and calculated using the steady‐state model of litter accumulation (k=L/X), overestimated the rate of litter disappearance and litter decomposition. For the overstorey leaves in particular, the loss constants also overestimated the rate of loss of material from the litter layer since the fragmented and consumed tissues accumulated in the fraction of comminuted fragments before moving into the humus/soil subsystem.A compartment model of the components of the litter layer in the mixed eucalypt forest is presented. It incorporates overstorey and understorey litter accession, accumulation and disappearance data. The adoption of a two dimensional decomposition/accumulation matrix is suggested as an appropriate framework within which to simulate the dynamics of the litter subsystem in mixed eucalypt forest ecosy

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01211.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe perennial grasses(Aristidaspp.) are invaders of the Mitchell(Astreblaspp.) grasslands of semiarid Queensland. The possible role of a number of physiological factors influencing the establishment and maintenance ofAristida leptopoda(white spear grass) andAstrebla lappacea(curly Mitchell grass) populations were examined in a series of experiments. Under controlled conditions, both seedling growth and root extension rates of curly Mitchell grass were far superior to white spear grass at a temperature of 30°C. However, at temperatures of 25°C and less, little species differences in these rates occurred White spear required a lower soil phosphorus concentration for optimum growth compared with curly Mitchell grass, but its yield response to increasing phosphorus concentration was much smaller than this species. Results of other studies suggested that relative drought endurance of established plants of these species to be related more to the amount and vertical distribution of the root system rather than to differences in stomatal contro

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01212.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractPollen data from the Rooty Breaks swamp – a Sphagnum bog surrounded byAtherosperma‐Elaeocarpusrainforest – in the eastern Victorian highlands appears to reflect changes in the mode of pollen and spore deposition at the study site, from the time sediments began accumulating at about 5500 BP until the present day. In the lower half of the deposit, pollen of rainforest taxa is more common than it is in the top half, whileEucalyptuspollen reflects the reverse situation. Although the pollen changes may reflect climatic change it is suggested that most of the pollen and spores in the lower sediment were stream‐borne. Later the stream moved away from the site and the records became more representative of atmospheric pollenrain. Throughout the period covered by the pollen diagram the Rooty Breaks swamp itself was dominated by Leptospermum grandifolium. The pollen record shows that the association of important taxa in rainforests of the highlands of eastern Victoria was established by at least 5500 BP.The presence of sparse old eucalypts throughout the area dominated by rainforest suggests that sclerophyll forest was replaced by rainforest in the recent past. However, this change is not evidenced in the pollen

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01213.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractMagela Creek is a hydrologically complex waterway which drains Australia's two largest uranium deposits, carries a pastoral and tourist industry and has been proposed for inclusion in a national park. In this study, the vegetation and stream patterns of the floodplain are described and are used as indicators of surface water movement through the system.The Magela floodplain was found to be a freshwater lagoon, enclosed at its outlet by, the floodplain of the East Alligator River; the vegetation types are direct indicators of water depth within the lagoon. The capacity of the lagoon is approximately 60 × 106m3, the average daily input during the wet season is approximately 3% of the lagoon volume and during the dry season the lagoon dries out to approximately 5 × 106m3of perennial swamp. The lagoon is maintained by the East Alligator River and so its hydrology must not be studied in isolation but in relation to the larger system to which it belong

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01214.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY