bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cluster analysis, ordination and dominance‐structural classification applied to diverse tropical vegetation at Jabiluka, Northern Territory
Authors: BURGMAN M. A. , THOMPSON E. J. 
Published: July 2006

AbstractOne hundred and seven sample plots were established on a study area at Jabiluka, Northern Territory, and detailed quantitative floristic and structural data were collected. Data collection was by sampling both on aerial photographs and in the field, and both sets of data were used to describe the primary floristic types and structural sub‐types. Cluster analysis (Orloci 1967, 1969), polar ordination (Mathews 1977) and Specht's (1970, 1977) approach to vegetation classification were used to analyse the data. Two independent clustering techniques, one based on art information measure and the other on a measure of within group dispersion, produced very similar dendrograms. The analyses consistently separated the plots into three major groups ‐ floodplain, dryland and sandstone landscapes; within these groups 15 floristic associations and eight structural formations were identified. The environmental parameters associated with the various groups were substrate type, and seasonal inundation from the Magela Creek system. The results of ordination did not highlight any environmental parameters not already made evident by cluster analysis.
In situ determination of nitrogen fixation in Antarctica using a high sensitivity portable gas chromatograph
Authors: DAVEY ALLAN 
Published: July 2006

AbstractA portable gas chromatograph was employed in the Vestfold Hills, Antarctica, during the austral summer of 1979‐80 for determining nitrogenase activity of the blue‐green alga Nostoc commune Vaucher by the acetylene reduction assay. Acetylene reduction was measured in samples taken along a transect where the vegetation changed with respect to differing topography and water availability. Submerged colonies of Nostoc recorded the highest fixation rates (6.89 nmol C2H4. cm‐2 h‐1). Damp mosscyanophyte associations growing on shallow slopes showed moderate rates of acetylene reduction (1.99 nmol C2H4. cm‐2 h‐1) whilst the drier vegetation of the steeper terrain was the least active (0.19 nmol C2H4. cm‐2 h‐1. The employment of a high sensitivity portable gas chromatograph provided an accurate and reliable method of measuring acetylene reduction.
A field device for integrating temperature sensed in grass or forest fires
Authors: HODGKINSON KEN C. , GORDON WILLIAM T. , SMITH DON L. 
Published: July 2006

AbstractA device for measuring the integrated temperature sensed by a thermocouple during a grass, forest or other landscape fire is described and its performance evaluated. It consists of a small tube containing an electronic circuit to which is attached a length of thermocouple wire. The tube is buried for the duration of the fire. Principal component of the circuit is an E‐cell (or microcoulometer) which when cleared allows calculation of the temperature/time integral. Performance was found to be reliable and accurate: because of its low cost it has widespread application for measuring the temperature in soil, plants or air during fires.
Short Note Strategy and tactics in pattern analysis: a response to Harrington, Dawes and Ludwig
Authors: DALE M. B. 
Published: July 2006

AbstractIn this paper the role of pattern analytic methods is examined. Recently Harrington et al. (1981) have argued that such methods provide no information which is not already available to the user and that they therefore must be considered useless. It is first suggested that Harrison et al. provided no proof that the information obtained from a pattern analysis was already known to them. It is further suggested that they have misunderstood the role of pattern analysis in the identification of processes for generation of variation in vegetation, restricting it solely to certain mathematical techniques of search. However the assignment of credit or debit to the various components of an analysis, where these include such things as choice of sample units, selection of descriptors, identification of appropriate accuracy and precision for measurement as well as the selection of similarity measures and structuring techniques, remains a very difficult task. Harrington et al. do not appear from their paper to have thoroughly explored all possibilities. In fact the results obtained by them reflect the complexity of the ecological situation. Thus the difficulty they had in interpretation reflects their desire for a simplistic solution. Whether changes in all features of the analysis can provide such a simple result is not known. However it can hardly be considered the fault of the analysis if no such simplicity exists.
Transplants along the vegetation gradient on central Australian sandridges
Authors: BUCKLEY R. 
Published: July 2006

AbstractTo assess the importance of static catenary factors in controlling the floristic gradient on central Australian sandridges, plant species characteristic of particular topographic zones were transplanted to zones outside their normal topographic range. Both upper‐slope species transplanted downslope, and lower‐slope species transplanted upslope suffered higher mortality than control plants transplanted within the same topographic zone.
The effect of cave microclimate on winter roosting behaviour in the bat, Miniopterus schreibersii blepotis
Authors: HALL LESLIE S. 
Published: July 2006

AbstractThe microclimate at Thermocline Cave (lat, 30° 45′S, long, 149° 43′E) was investigated by measuring air temperature and relative humidity at five stations on 18 occasions from September 1971 to December, 1973. The activity, body weight and roosting sites of the bat Miniopterus schreibersii blepotis in the cave were recorded on each visit.Relative humidity in the cave was generally high and paralleled temperature. The cave exhibited a range of temperatures from 9 to 19.5°C but bats selected roosting sites only in a part of this range. During the autumn when the bats arrived and were feeding, their body weights were low, and they roosted in a domed area at the rear of the cave with a temperature of 19.5°C. As they became less active and body weight increased they moved to cooler parts (9.5‐11°C) towards the front of the cave and underwent periods of torpor, in one case lasting for at least 12 days. From July to September body weight decreased. The bats became more active in September and most had left the cave by October.It appears that M.s. blepotis can detect temperature differences of 1°C. They used this ability to select cold areas with stable high humidity in Thermocline Cave to under go periods of winter torpor.
Sexual differences in the foraging behaviour of the frill‐necked flycatcher Arses telescopthalmus in New Guinea
Authors: BELL H. L. 
Published: July 2006

AbstractThe foraging behaviour of male and female Arses telescopthalmus was studied at Brown River, Papua New Guinea. Significant differences exist between the sexes. The male mainly frequents the lower understorey and forages substantially on bare substrates, particularly vertical ones such as trunks and hanging vines. The female occurs mainly higher in the subcanopy, sallies frequently after aerial insects and forages mainly off leafy substrates. Both male and female show morphological adaptations to their specialized roles. Sexual differences in a species’foraging behaviour usually occur in depauperate avifaunas but the study area is rich in potential competitors of Arses. It is suggested that past environmental fluctuations may have initiated differentiation of male, female or both.
Litter production and decomposition from an overstorey of Eucalyptus spp. on two catchments in the New England region of New South Wales
Authors: PRESSLAND A. J. 
Published: July 2006

AbstractLitter fall on two catchments, one with an almost continuous canopy of Eucalyptus spp., the other with a discontinuous eucalypt canopy was measured for 29 4‐week periods. Annual litter accretion(2.5‐3.7 t ha−1) was low by world standards, but similar to other Australian dry sclerophyll forests. Between 33 and 54% of the total litter fall occurred during summer, and only 6‐13% in winter. Leaf was the major component of litter fall and usually contributed more than 50% of the total. Variability between the 4‐weekly litter falls was high, but coefficients of variation for the total annual fall were low (<5%).Half‐life of total litter fall in the continuous forest (2.14 y) was double that in the discontinuous forest (0.98 y), and may have been due to differences in air temperature and surface soil moisture.The pattern of litter fall on each catchment was related to hydro‐meteorological variables including air temperature, solar radiation, rainfall and soil moisture content.
Evidence against primary microclimatic control of the dune‐swale floristic gradient on central Australian sandridges
Authors: BUCKLEY R. C. 
Published: July 2006

AbstractThere are distinct and consistent soil and vegetation gradients between the dune‐crests and swales of the central Australian sandridges. If there is a corresponding dune‐swale microclimatic gradient, it is assumed to be controlled by topography. In general, soil characteristics and topography are closely correlated, but where they diverge, vegetation follows soil rather than topography. Hence if any duneswale microclimatic gradient exists, it is not a significant factor in controlling the dune‐swale floristic gradient.
Short Note On the apparent anomaly between observed and predicted percentages of vegetation types in south‐west Tasmania
Authors: BROWN M. J. , PODGER F. 
Published: July 2006

AbstractThere is an anomaly apparent between the estimated percentage of area of rainforest in south‐west Tasmania and the amount predicted by a Markovian model based on fire frequency. The anomaly results from a misinterpretation of the original reference. The predicted percentages of vegetation types are in broad accord with present day distributions, and variations can be explained by relatively minor shifts of fire frequency estimates.
Altitudinal and successional variation in the vegetation of the northern part of the West Coast Range, Tasmania
Authors: KIRKPATRICK J. B. 
Published: July 2006

AbstractThirteen floristic communities are recognized by numerical analysis of the vegetation of a part of the West Coast Range containing the climatic station with the highest mean annual precipitation in temperate Australia, and a variation in altitude from 400 to 1200 m. These communities form an altitude‐related sequence with a perceptible break at the transition to alpine vegetation. Within rainforest three intergrading groups also form an altitudinal sequence. However, total environmental stress, as reflected in growth rates, is hypothesized to control this floristic and richness gradient. Direct and indirect gradient analysis reveals a lowland successional sequence from sedgeland to rainforest. Although some alpine communities are clearly the product of firing of others, there is no analogue of the lowland sedgelands. Fire‐induced change in both alpine vegetation and rainforest can be extremely long term. Soil drainage is important in the differentiation of both lowland and alpine communities.
Growth energetics in relation to temperature for larvae of four species of necrophagous flies (Diptera: Calliphoridae)
Authors: WILLIAMS H. , RICHARDSON A. M. M. 
Published: July 2006

Abstract The growth characteristics of the larvae of the major members of a necrophagous fly guild in Tasmania (Lucilia cuprina, Calliphora stygia, Calliphora vicina and Calliphora hilli) were measured to assess their competitive ability. The measurements were made at temperatures between 10 and 45°C, to cover the range of temperatures that would be encountered by larvae in carrion or myiasis under field conditions. The characteristics measured were net production and respiration. The indices K2i (instantaneous growth efficiency), K2c (cumulated growth efficiency) and Mi (instantaneous cost of maintenance) were calculated. Generally K2c and K2i are highest and Mi lowest at 25°C for all the species. A sinusoidal response in K2c, K2i and Mi against temperature is seen for L. cuprina, C. stygia and C. vicina. This response is‘cold’adapted in the Calliphora species and‘warm’adapted in L. cuprina.Egg size, egg caloric density and the energy content of the eggs are discussed in relation to the‘fitness’and reproductive strategies of the four species. The thermal tolerance range of L. cuprina determined here suggests that carrion may provide a significant number of this fly particularly in areas where Chrysomya spp. do not occur, and in large carcasses where temperatures are elevated.
Drought and dieback of rural eucalypts
Authors: LANDSBERG J. 
Published: July 2006

AbstractThe possibility that drought causes dieback of eucalypts in rural Australia was investigated. Water potential and canopy condition in dieback and healthy rural Eucalyptus blakelyi and E. melliodora trees were compared during and after an extreme drought in the ACT. All the trees were drought affected, but the extent was independent of the condition of their canopies at the beginning of the study.
Experimental confirmation of competition between two dominant species of Iridomyrmex (Hymenoptera: Formicidae)
Authors: FOX BARRY J. , FOX MARILYN D. , ARCHER ELIZABETH 
Published: July 2006

AbstractThe well‐defined ant succession following disturbance of coastal heathland in eastern Australia includes community replacement triggered by one dominant species of Iridomyrmex (species C) being replaced by another (species A). This paper investigates the consequences of experimentally reducing the abundance of species A by injecting petrol into the nest entrances of colonies. The response of species C was monitored at 2 and 10 months after removal and shows highly significant increases in the number of pitfall traps occupied and the area of territory maintained by this species.It is confirmed that interspecific competition plays an important role in maintaining the observed mosaic pattern of ant distribution and is also important in ant succession. The mechanism of competition is interference or, more exactly, territorial competition. The species appear to actively defend territorial space by patrolling territory boundaries that are breached when the defenders are eliminated.
Pasture seed dynamics in a dry monsoonal climate. I Germination and seedbed environment of Stylosanthes humilis and Digitaria ciliaris
Authors: McKEON G. M. , ROSE C. W. , KALMA J. D. , TORSSELL B. W. R. 
Published: July 2006

AbstractField germination behaviour and seedbed environment of the annual legume Townsville stylo (Stylosanthes humilis) and the vigorous annual grass weed (Digitaria ciliaris) were studied at Katherine, Northern Territory. Previous studies of the population dynamics of these pastures had indicated the importance of the germination‐establishment phase in maintaining S. humilis as a pasture component.Analysis of seed samples at the time of sward establishment showed that near complete germination of viable seed (in the case of D. ciliaris) and of soft seed (in the case of S. humilis) occurred in the early storm period before the onset of the wet season. Swards of both species generally resulted from a single, major germination wave often after an isolated rainfall.The seedbed environment at the time of major germination waves was studied in detail for 2 years and environmental models were used with historical climate records to calculate probability distributions of temperature and moisture over 16 years. The main determinants of the seedbed environment were storms (most often occurring in the period from late afternoon to midnight) and high solar radiation levels (70% > 20 MJ m‐2 day‐1 in the days after rainfall. Surface soil generally dries to ‐1.5 MPa by noon. Minimum night surface temperatures showed little variation (∼25°C) and were followed by high surface temperatures the following day (> 35°C). The use of a simple water balance model showed a high chance (80% of events) of the top 40 mm drying to – 1.5 MPa at the end of the second day following rainfall.Despite the low variation of annual rainfall at Katherine (cv of 20%) these self regenerating annual species have a high risk of seedling death. Germination and seedling establishment take place at a time of rapid fluctuations in surface moisture and seedbed temperature. The analysis of seedbed conditions indicated that intensive sampling of the seed population would be required in the early storm period to explain differential survival of the species and that laboratory work should concentrate on factors controlling speed of germination over short periods of available moisture (12–20 h).
Pasture seed dynamics in a dry monsoonal climate, II The effect of water availability, light and temperature on germination speed and seedling survival of Stylosanthes humilis and Digitaria ciliaris
Authors: McKEON G. M. 
Published: July 2006

AbstractEnvironmental factors affecting speed of germination and survival of naturally occurring seed of the legume Stylosanthes humilis and the grass Digitaria ciliaris were studied. Previous studies on the seedbed environment had shown that germination speed, defined as the proportion of seeds capable of germinating in the first 12 h period, was likely to be the most relevant laboratory measurement. Ten studies were conducted to compare species performance and to devise a standard technique for the measurement of germination speed under laboratory conditions.For S. humilis, the level and duration of submergence in water in the germination test had a large effect on germination speed (from 0–70% in 12 h). The absence of light delayed germination (7% in 12 h compared to 52% under light), but did not prevent complete germination over 7 days. Optimum temperature was 25°C with a decrease to 0% at 30°C. A standard technique was developed for measuring potential germination speed which gave reproducible results allowing differences in seed lots to be described. D. ciliaris seeds sampled just prior to field germination in the early storm period were less sensitive to environmental control. Temperature optimum for germination decreased from 40 to 30°C with the duration of the germination test. Seeds sampled at the time of seed dispersal (early dry season) had a high fraction (80%) requiring light for germination but this requirement had been lost by the early storm period.Investigations on the role of leaching (water movement) showed that long periods of water movement (12–18 h) increased the speed of germination of both species and in the case of S. humilis overcame environmental blocks to rapid germination (absence of light or 30°C temperature).Root elongation rates in S. humilis were not greatly affected by temperature over the range of seedbed temperatures when moisture is available (25–40°C) in the field. However, D. ciliaris was delayed in development at 25°C, the most likely overnight surface soil temperature. D. ciliaris was more susceptible to death by desiccation once germination had occurred compared to S. humilis. In both species seedling death due to desiccation increased with stage of development.The better relative performance of S. humilis in the germination‐establishment phase of the life cycle, which had been observed in a previous study, could be explained by a qualitative comparison of the species' attributes. This suggested that D. ciliaris was more likely to germinate at rainfall events following which there was a greater chance of seedling death
Comparison of insects and vertebrates as removers of seed and fruit in a Western Australian forest
Authors: ABBOTT IAN , VAN HEURCK PAUL 
Published: July 2006

AbstractRemoval from the forest floor of seed or fruit of the six commonest species of trees in upland areas of the northern jarrah forest of Western Australia was studied experimentally. The smallest seeds (Eucalyptus marginata, Allocasuarina fraseriana) were taken by insects (presumably ants). Heavier seeds or fruits (E. calophylla, Banksia grandis, Persoonia longifolia, P. elliptica) were taken more often by vertebrates (presumably srrmll mammals). Seeds of E. calophylla and B. grandis were most preferred by vertebrates, possibly because they have the highest relative concentrations of nitrogen and phosphorus.
Seed release in Banksia: the role of wet‐dry cycles
Authors: COWLING RICHARD M. , LAMONT BYRON B. 
Published: July 2006

AbstractSeed release in two serotinous and two nonserotinous Banksia species from southwestern Australia increased many fold when burnt cones were subjected to wet‐dry cycles compared with those remaining air‐dry. The response was temperature‐dependent, increasing markedly in treated cones of B. leptophylla as temperature was lowered from 30 to 15°C. This episodic wetting requirement at cool temperatures for prolific seed release implies that, following summer fruit opening, dispersal is delayed until the onset of late autumn/early winter rains when conditions are suitable for germination (optimum at ∼15°C) and recruitment. Seed loss from post‐dispersal predation and exposure to high summer soil temperatures also would be minimized.
Dispersal of the winged fruits of Nuytsia floribunda (Loranthaceae)
Authors: LAMONT BYRON 
Published: July 2006

AbstractFruits of the tree Nuytsia floribunda are dispersed by wind during autumn to mid‐winter when conditions are suitable for germination. While the greatest density of fallen fruits occurs beneath the canopy, most are dispersed well beyond the tree in the direction of the prevailing west‐southwesterly winds, with a minor peak corresponding to the easterlies. A multiple regression equation, which accounted for 77.5% of variance, was derived to account for the greatest dispersal distance per tree. This comprises, in decreasing order of importance, tree height, log (fruit load), and leeward and windward plant cover in the vertical plane. Extrapolation indicated a maximum distance of about 50 m can be expected, which is insufficient to account for the location of at least 6.5% of adult trees at the study site. This supports other evidence that suckering may play a major role in the spread of this species. Additional experiments confirmed the importance of wind velocity in the distance reached by fruits and the absence of biotic dispersal agents.
Food and foraging behaviour of the lizard, Ctenotus taeniolatus
Authors: TAYLOR JANET A. 
Published: July 2006

AbstractA sample of 261 Ctenotus taeniolatus revealed that this species of skink is principally insectivorous, the most common foods being lepidopteran and coleopteran larvae, orthopterans and formicids. The occurrence of these foods in the diet followed seasonal patterns. The prey of adults and juveniles did not differ qualitatively, although adults were capable of eating a greater diversity of prey sizes than juveniles. Lizards used both sit‐and‐wait and active foraging strategies, with adults and juveniles exhibiting these behaviours in different ratios.