摘要:

AbstractIn the first comprehensive floristic classification of Australian rainforests and monsoon forests, fresh insights made possible by the use of floristic as distinct from structural data are outlined. A set of 561 individual communities, on sites ranging from North Queensland westwards to the Kimberley region and southwards to Tasmania, is defined by the presence or absence of 1316 tree species, or 406 genera. The data have been subjected to numerical classification, first with respect to species, then to genera.The species classification first divides into three ‘ecofloristic regions’: A, temperate (microtherm) and subtropical (mesotherm) humid evergreen rainforests; B, tropical (megatherm) humid evergreen grading into highly seasonal raingreen (monsoon) forests; and C, subtropical (mesotherm) moderately seasonal humid/subhumid raingreen forests. The sites are further divided into eight ‘ecofloristic provinces’, for each of which a core area is identified and the ten most common diagnostic tree species listed for selected floristic elements, whose ecological relationships are briefly described.Gradients of quantitative thermal‐moisture indices are added to standard climatic typology to provide a more flexible identification of local climates that characterize community‐types of each province across a wide latitudinal/altitudinal range. Community disjuncts and outliers of a particular province are interpreted as the results of past environmental sifting (in which ecological factors are not entirely determinate), of previously more continuous rainforest vegetation.The genera classification first divides into humid eastern coastal and subhumid western and subcoastal sites, then four thermal types, and finally nine groups of floristic ‘paleo‐provinces’. Where the species and genera classifications are not in substantial agreement, a wide‐ranging generic element across the provinces in northern and northeastern Australia is interpreted in paleogeographic terms.The relict distribution of existing community types, as the result of climatic sifting of ancient floral stocks, is discussed in support of emerging ideas about the autochthony of Australian rainforests, especially those tropical types that are not intrusive.It is argued that the unique ecological relationships of Australian rainforests justify the most conservative uses of the relatively sm

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1984.tb01356.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

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 ofMelaleucaswamp 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 byMelaleucatrees, 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 minin

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1984.tb01357.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

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.

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1984.tb01358.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractNearly 1500 foliage samples were collected from a total of 156 plant species, distributed at 16 study sites representing a wide range of forests and woodlands in south‐eastern Australia. Samples were collected in all months. Invertebrates present in samples were counted, sorted into 13 categories, and the number present (>3 mm in length) converted into density estimates. Densities of all invertebrates combined and invertebrate diversity were also calculated.Despite high variability there were some obvious distributional patterns for most categories. Three major dichotomies affected abundance and distribution of invertebrates: these were presence or absence of flowers, whether the plant species wasEucalyptusor other, and ifEucalyptus, whether the plant species wasSymphyomyrtus or Monocalyptus. The presence of flowers in foliage samples increased the abundance of most invertebrate taxa. Compared to foliage of non‐Eucalyptusspecies,Eucalyptusfoliage had more lerp‐forming psyllids and miscellaneous larvae, but fewer Arachnida, Coleoptera, Psocoptera, Hemiptera (other), Thysanoptera, Diptera, and total arthropods. Foliage ofSymphyomyrtusspecies had higher densities of most categories (and particularly lerp‐forming psyllids) than that ofMonocalyptus.There were seasonal variations in abundance in most invertebrate taxa, but these patterns were different forEucalyptusand non‐Eucalyptusspecies. For most sites abundance of all arthropods combined was lowest in winter, but this decline was not especially pronounced, and was reversed at more xeric sites.For most categories there were significant differences between study sites in abundance and for some this was related to position of sites on a moisture gradient. In general total arthropod densities were highest at intermediate and xeric sites. There were some significant differences in arthropod communities for the same plant species at different study sites.Sample height, plant height, and the ratio of these were relatively unimportant variables. Likewise, the ratio of leaf width: leaf length was not significantly correlated with abundance for any invertebrate category across 128 plant species, but mean leaf size was negatively correlated with densities of Arachnida and total invertebrates. The distributions of some invertebrate categories were inter

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1984.tb01359.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe parapatric boundary between the reptile ticks.Aponomma hydrosauriandAmblyomma limbatum, near Mt Mary, South Australia, coincides with a vegetational ecotone. Samples of litter from each side of the tick boundary showed considerable heterogeneity, but there were consistent differences in the composition and quantity of litter. North of the boundary, whereAmb. limbatumis found, there is less litter and an absence ofEucalyptusleaves in the litter. Since the litter retards evaporative water loss, andAp. hydrosauriis less tolerant of dehydration, reduced litter quantity may reduce the fitness of colonizingAp. hydrosauri. In laboratory and field trials, larvae and nymphs of both tick species chose litter microhabitats in preference to bare soil, with the exception of fedAp. hydrosaurilarvae which, in trials with litter from north of the boundary, rarely moved from the bare soil. This behaviour may also reduce the fitness of colonizingAp. hydrosauri.The two species adopted different positions in the litter.Ap. hydrosauriwere predominantly found on the surface, at the interface between soil and litter as fed larvae, and on or under the surface as nymphs.Amb. limbatumlarvae were more often buried under the surface, while nymphs were found mostly in the litter above the soil surface. Hypotheses to explain the maintenance of the parapatric boundary are discussed in the light of these results.

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1984.tb01360.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractChanges during regeneration after sand mining for heavy minerals were studied on an area that previously supported open‐forest on the Holocene high dune system in Myall Lakes National Park. Sixteen study areas, on which topsoil was replaced 0.5–10 yr ago, provided information on changes to be expected on any one site over that time period. A number of environmental variables was used in a linear multiple regression analysis to determine which of them is important in accounting for the variance and patterns observed in the biomass of two rodent species colonizing the regenerating areas.The first small‐mammal colonist is the introduced house mouse (Mus musculus), an opportunistic species present on all sites. Its population density increases rapidly to a maximum at 3 yr after which it declines. Three environmental variables: percentage of bare sand, hardness of the soil in the first 30 cm, and a vegetation structure variable, account for 73% of the variance inM. musculusbiomass.The native New Holland mouse (Pseudomys novaehollandiae) first appears between 4 yr and 5 yr after topsoil replacement and peaks between 8 yr and 9 yr, after which it also declines. A highly significant multiple regression accounts for 69% of the variance inP. novaehollandiaebiomass using five significant variables: the proportíon of heath plants present, two vegetation structure variables, the amount of dead plant cover, and the topsoil depth. The species replacement observed confirms the succession indicated by previous work and suggests competitive interaction between these species.This study confirms the seral positions of rodent species in successions following both mining or fire. There is a stretched time axis for the mining succession following the more complete disruption of the substrate so regeneration more closely approximates primary rather than secondary succession. The non‐linearity of the parameters makes it impossible to predict a recovery time and verifies our previous prediction that recovery estimates from heathland should not be extrapolated t

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1984.tb01361.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractPotential insect migrants were sampled by light‐trap at a remote island in the Coral Sea from 15 December 1977 to 30 November 1978 (351 nights). Breeding requirements, seasonal abundance and frequency, wind trajectory relationships, and known migratory tendencies of the 115 taxa collected, were analysed to detect those species migrating overseas from distant land sources. Thirteen influxes were detected from Queensland (minimum crossing 450 km) and one possible influx from Papua (600 km), involving 24 species (83 individuals) unable to reproduce on the island, and up to a further 27 species (73 individuals) among which there was a strong circumstantial evidence of immigration and little or no local reproduction. Sixty seven species (including three of the above putative immigrants) bred on the island and 45 of these were very abundant (99.7% of the total catch of 105480). Long‐range migration is known to occur in most of the latter 45 species, but could not be detected in this study because of the extent of local flight activity. Such activity probably led to a substantial emigration of insects from the island. To sustain the observed rates of colonization, large numbers of migrants, representing most insect orders, must be leaving potential source areas in northern Australia and New Guinea during periods of off‐shore

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1984.tb01362.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractIndirect gradient analysis, which entails the elucidation of relationships between trends in community composition and underlying environmental or successional gradients, is a major objective of ordination in plant ecology. Two ordination techniques, detrended correspondence analysis (DCA) and principal co‐ordinates analysis (PCOA), were compared using three sets of Tasmanian vegetation data having known gradients and one set where the vegetation was expected to respond to diverse environmental variables. In every case, the results obtained by DCA were considered superior to, or at least as good as, those of PCOA. Hence, DCA appears to be the more suitable of the two methods for indirect gradient analysi

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1984.tb01363.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe effect of sampling strategy on animal‐habitat relationships was evaluated with data collected from a 50 ha area containing a sequence of tropical vegetation types.Sampling sites were located randomly within defined habitat types (i.e. stratified random sampling) and systematically irrespective of habitat type. At each site the fauna, comprising birds (63 species), reptiles (15 species), amphibia (13 species) and grasshoppers (32 species) were sampled for the abundance of species. Simultaneously, vegetation and related data, comprising vertical structure (52 attributes), ground surface condition (18 attributes), plant lifeform (18 attributes) and the abundance of plant species (200) were recorded.Random and systematic data matrices, comprising sites defined by animal or vegetation attributes, were reduced dimensionally by correspondence analysis. Animal first dimension vectors were then regressed on the first dimension vectors of vegetation structure, lifeform and floristics, respectively.With stratified random sampling, vegetation structure (comprising vertical and ground attributes) and lifeform explained most of the variation in the fauna; floristics were not a significant factor. On the other hand with the systematic data, fioristics explained almost all of the variation in animal abundance and distribution. By removing the ecotonal sites from the systematic data set and recalculating vectors, the animal—vegetation relationships became similar to those generated from the stratified random sampling data.Clearly, the sampling strategy employed in a faunal survey has a major influence on the inventory of species, and on the relative importance of vegetation structure, lifeform and floristics in explaining animal distribution. The presence of ecotones in the systematic data set was highlighted as the key to the difference between the sampling strateg

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1984.tb01364.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractAn extension to the Leslie matrix is presented in which the age of transformation from immature to adult has a log—normal distribution. The major effect of this is shown to be on the second largest eigenvalue. The ratio of the largest to the second largest eigenvalue |λ1/λ2|, which is an index of the rate of approach to the stable age distribution, is greater in the new model, even though the value of λ1is effectively the same. The differences in the models are most pronounced where the population is subjected to a harvesting re

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1984.tb01365.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY