摘要:

AbstractModern pollen representation of aquatic vegetation communities at three sites on the Atherton Tableland is examined. Indicator pollen taxa are identified and are used to interpret the aquatic pollen components of two pollen diagrams from one of the sites. It is believed that detailed estimates of changes in lake water level have been derived from the identified fossil plant communities.

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01217.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractIn an unburnt, mature forest the germination ofE. regnanson undisturbed bare ground is very poor in spite of adequate seed fall, and the presence of conditions suitable for germination over much of the year. No seed storage occurs in the top soil in spite of some temporary seed dormancy and the disturbance of the surface soil by earthworms and lyre birds. Seed is removed from the top soil by several ant species– Prolasius pallidus, P. brunneus, P. flavicornisandChelaner leae –and is taken into nests. Removal of seed is more rapid and complete in summer than winter and is more vigorous in young forest than old. Observations on artificial nests in the field and laboratory indicate that seed is eaten and not stored for any length of time. The testae may be left intact, fragmented or moulded into crumbs with other material. Certain sugar‐like substances, which are extractable in low concentrations from fresh seed, may be involved in the attractivity of seed to ants. The numbers of ant species in the forests vary with the micro‐climate of the site, and in the mature understorey ofPomaderris asperathe activities of the three dominant speciesIridomyrmex biconvexus, Prolasius pallidusandP, hrunneusare largely separated diurnally, seasonally, and spatially in the foraging areas of the litter layer. The density of the nests of seed‐harvesting ants is high, particularly in bare areas of the forest floor. The total number of ants probably exceed 5–6 million/ha and is probably sufficient to effectively remove 60% of the sporadic seed fall of normal years. It is suggested that the success of germination ofE. regnansafter wild fires is not due to any specific stimulation but rather to a temporary interference of ant foraging activity and then to the saturation of their food requirements by a massive seed fall from canopy‐st

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01218.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractAn area of jarrah(Eucalyptus marginataSm) forest was burnt with a hot fire (ca 600 kw/ha) in March 1975. The meso‐ and microarthropod faunas were sampled in May, June and July 1976 and the decomposer activity of the soil and litter was estimated using buried cotton strips. The growth of jarrah seedlings in pots was measured under different litter and nutrient regimes. Feeding experiments withEucalyptus, BanksiaandBossiaealitter were carried out onPodykipussp., a litter millipede common at the site of the fire.Burning reduced the numbers of arthropods, the proportion of juveniles and the proportion of fungal feeders in the micro‐arthropod population. The rate of decomposition was also reduced. The seedlings grew most under leaf Utter and millipede faeces and least under leaf ash.Podykipussp. preferredBossiaealitter (high nutrient content) to eitherEucalyptusorBanksialitter (low nutrient conte

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01219.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe aim of this study was to describe the forest vegetation along an altitudinal transect running from 158 m to 1220 m (treeline) in the Mount Field National Park, Tasmania. Eighteen 1 ha plots were sampled along this transect, using a modified point‐centred quarter method for species composition and density. Size frequency distributions were used to calculate basal areas. Estimates of relative density, frequency and basal area for each species were combined in to an importance value. The altitudinal ranges of all woody species were determined. The altitudinal temperature lapse rate was measured, and data on soil pH obtained.The initial ‘direct gradient’ analysis revealed relatively well marked discontinuities in the vegetation which were further examined by ordination and classification techniques. The latter provided a simple threefold classification into altitudinal zones. The lower zone reaches from the Park entrance (158 m) to between 600 and 670 m, and comprises tall open forest dominated byEucalyptus regnansand/orE. obliquaand with a ‘wet sclerophyll’ understorey characterized byOlearia argophylla.The middle zone stretches fromc.670 to 940 m and comprises closed rainforest or ‘mixed’ forest (i.e. with senescent emergent eucalypts) dominated byNothofagus cunning hamiiandAtherosperma moschatum.This zone is characterized by the absence ofO. argophyllaand the presence ofPhyllocladus aspleniifolius.The upper part of this zone constitutes an interdigitating transition to the subalpine forests, usually dominated byE. cocciferaand occurring on suitable sites betweenc.880 m and the timberline. The transition to subalpine forests is associated with a marked decline in basal area.Species richness (of woody plants) increases with altitude to reach a peak in the sub‐alpine zone. This trend is the reverse of that normally encountered elsewhere in the world, and is mainly due to relatively high α and β diversities in the shrub stratum of this zone.The significance of fires, aspect and substrate is discussed in relation to the variations in composition within each zone. The low diversity ofNothofagus‐dominated rainforest is thought to be due, in part, to the intense competitive thinning in the eucalypt re‐growth phase following burning, and the subsequent ‘capture’ of theEucalyptusniche byNothofagus.It is speculated that, in Tasmania, the downhill migrations during the cooling phases of the Pleistocene were associated with extinctions of lowland forest taxa, while uphill migrations during warming phases were associated with speciation on the plateaux of the present subalpine zone. This hypothesis implies that the relative proportions of land area available at different altitudes, now and in the past, have determined the relative rates of speciation and extinction, and hence the altitudinal grad

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01220.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractStudies of the species richness and equitability were made of coastal birds at Darwin, Northern Territory, following censusing. A general decrease in numbers and species richness of indigneous and palaearctic migrants occurred in the wet season. Equitability values were depressed at the beginning of the wet season indicating an ecologically disturbed situation Freshwater discharge and its complex mixing patterns in neritic and estuarine water may be responsible for such a disturbance through its effects on the bird's food supply.

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01221.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe effects of high intensity fire on the cycling of nutrients in litter and canopy through fall were studied in pole stand jarrah(E. marginataBonn ex Sm.) forest near Dwellingup, south‐western Australia. In the first year following burning, twice as much litter fell on the burnt site as on an unburnt control site. Concentrations of phosphorus and nitrogen were higher in post‐fire litter probably because crown scorch during burning prevented withdrawal of phosphorus and nitrogen into the tree before leaf fall. This, together with the increased weight of litter, resulted in a four‐fold increase in the accession of phosphorus and nitrogen to the forest floor in litter one year after the fire on the burnt site. The concentrations of potassium, magnesium, sodium and chlorine in the litter were all significantly lower on the burnt site than on the unburnt site in the first year following burning.During the second year after the fire, significantly less litter fell on the burnt area than on the unburnt control site. Phosphorus concentrations in the litter from the burnt site remained 50% higher than in litter from the control but the other nutrient elements returned to their pre‐fire levels.There are indications that more phosphorus and potassium are cycled via canopy leaching immediately after burning. In the second winter following the fire there were no significant differences in the amounts of nutrients in canopy leachate on the burnt and unburn

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01222.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The dispersal and ecology of the Diamond Back moth,Plutella xylostella(L.), in Victoria Stephen Goodwin

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01223.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Book review in this articleBASIC Interactive Computer Models in Population Dynamics L. ROGER KITCHINGThe Disappearing Heath J. B. Kirkpatrick ELAINE M. BIRK

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1979.tb01224.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY