bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal changes in germination responses of buried seeds of the weedy summer annual grass Setaria glauca
Authors: BASKIN G C. , BASKIN J. M. , EL‐MOURSEY S. A. 
Published: July 2006

SummarySeeds of Setaria glauca (L.) Beauv. buried in soil and exposed to natural temperature cycles exhibited seasonal changes in temperature, but generally not light; dark requirements for germination. Seeds were dormant at maturity in late September and October (autumn), and during burial from October to January they entered conditional dormancy, germinating up to ≥60% in light and darkness at daily thermoperiods of 25/15,30/15 and 35/20^C by January. During burial from February to May or June, seeds became non‐dormant and germinated up to 68–100% in light and darkness at 15/6,20/10,25/15,30/15 and 35/20^C in May or June. At maximum yearly temperatures in June or July–August, 65–89% of the seeds entered conditional dormancy (germinating at 30/15 and 35/20, but not at 15/6,20/10 and 25/15^C), and the others entered dormancy (not germinating at any thermoperiod). Thus, most buried seeds had an annual conditional dormancy/non‐dormancy cycle, but some had an annual dormancy/non‐dormancy cycle. Except for seeds buried in 1990 that lost the ability to germinate in darkness at all thermoperiods the first summer of burial, seeds incubated in light and in darkness exhibited the same patterns of seasonal changes in germination responses. Although conditionally dormant and non‐dormant seeds germinated to high percentages in darkness in Petri dishes, seedlings were found only in bags of seeds exhumed in April and May 1983, indicating that some factor(s) associated with the burial environment other than darkness prevented germination of buried seeds.
Synergistic joint action of MCPA ester and metsulfuron‐methyl
Authors: HOLLAWAY K. L. , HALLAM N. D. , FLYNN A.G. 
Published: July 2006

SummaryMCPA is antagonistic to a range of herbicides but there is limited research on its compatibility with other broad‐leaved weed herbicides. In this study we assessed the joint action of MCPA ester and metsulfuron‐methyl on Brassica napus L. using the additive dose model (ADM). The fresh weight responses for selected ratios of the mixture were plotted on the ADM and compared to the predicted mixture response at three assessment levels ‐ 50, 75 and 90% control. The mixture demonstrated increasing synergism as the response level increased from 50 to 90%. This result for MCPA ester is in marked contrast to that of the MCPA amine formulation, which was shown in previous studies to be antagonistic towards sulfonylurea herbicides. Formulation is the major deciding factor in determining the compatability of phenoxy herbicides with other herbicides.
Prediction of the competitive effects of weeds on crop yields based on the relative leaf area of weeds
Authors: LOTZ L. A. P. , CHRISTENSEN S. , CLOUTIER D. , QUINTANILLA C. FERNANDEZ , LEGERE A. , LEMIEUX C. , LUTMAN P. J. W. , IGLESIAS A. PARDO , SALONEN J. , SATTIN M. , STIGLIANI L. , TEI F. 
Published: July 2006

SummaryFor implementation of simple yield loss models into threshold‐based weed management systems, a thorough validation is needed over a great diversity of sites. Yield losses by competition wsth Sinapis alba L. (white mustard) as a model weed, were studied in 12 experiments in sugar beet (Beta vulgaris L.) and in 11 experiments in spring wheat (Triticum aestivum L.). Most data sets were heller described by a model based on the relative leaf area of the weed than by a hyperbolic model based on weed density. This leaf area model accounted for (part of) the effect of different emerging times of the S. alba whereas the density model did not. A parameter that allows the maximum yield loss to be smaller than 100% was mostly not needed to describe the effects of weed competition. The parameter that denotes the competitiveness of the weed species with respect to the crop decreased the later the relative leaf area of the mustard was determined. This decrease could be estimated from the differences in relative growth rate of the leaf area of crop and S. alba. However, the accuracy of this estimation was poor. The parameter value of the leaf area model varied considerably between sites and years. The results strongly suggest that the predictive ability of the leaf area model needs to be improved before it can be applied in weed management systems. Such improvement would require additional information about effects of abiotic factors on plant development and morphology and the definition of a time window for predictions with an acceptable level of error.
Flowering phenology, seed set and bird pollination of five Western Australian Banksia species
Authors: WHELAN ROBERT J. , BURBIDGE ALLAN H. 
Published: July 2006

AbstractFlowering phenology and seed set characteristics of five species of Banksia were studied in relation to the nectarivorous birds which feed at their inflorescences. Within the Banksia woodland at the study site near Perth, the flowering seasons of the Banksia species were sequential and only slightly overlapping, providing a year‐round nectar source. Although honeyeaters visited alt five species, seed set was very low in each case. Caging experiments indicated that, in B. attenuata at least, alternative pollinators may play a more important role in pollination than do nectar‐feeding birds. It is suggested that non‐avian pollinators, predatory insects, and characteristics of the breeding system may also have been important in the evolution of the observed flowering phenology and patterns of seed set.
Post‐fire succession in the northern jarrah forest of Western Australia
Authors: BELL DAVID T. , KOCH JOHN M. 
Published: July 2006

AbstractPost‐fire species changes were documented over a portion of the northern section of the jarrah forest of Western Australia from a series of sites of known age since last fire. Species richness and species diversity were observed to increase following fire for several years, followed by a gradual decline. Dominance‐diversity curves indicated that maximum diversity occurred from 3 to 5 years following fire. The species composition of sites of different regions was more similar than sites of similar time since burn. The significance of the results to the programme of controlled burns is discussed.
Composition, spatial and temporal variability of the soil seed pool in a Eucalyptus populnea shrub woodland in central New South Wales
Authors: HODGKINSON KEN C. , HARRINGTON GRAHAM N. , MILES GRAEME E. 
Published: July 2006

AbstractThree sites in a Eucalyptus populnea woodland in central New South Wales were sampled for the number and composition of seed in the surface cm of soil. There was a total of 3200 seeds/m2 beneath eucalypt canopy, 13800 seeds/m2 in grassy inter‐tree areas and 4000 seeds/m2 in bare inter‐tree areas in April, 1975. These numbers were reduced by 23, 73 and 66% respectively during the subsequent 10 months, when there was no addition of seed. This decline was thought to be mainly due to predation, with germination as a secondary factor. Species composition of the seed pool differed between the three sites with seed of some species being only found beneath the eucalypt canopy or in the inter‐tree areas. There were no seeds that were not present as plants in the community. Any attempts to restore this woodland to its former grassy nature should take into account the low seed population of many of the formerly common grass species and the high number of shrub seeds (>200/m2). Species distribution of seed was highly heterogeneous making adequate sampling very difficult. Extracting and identifying the seed took 8 to 12 man‐h per 100 g sample.
The formal definition of the environment of an animal
Authors: NIVEN B. S. 
Published: July 2006

AbstractThe article describes the first step in the formalization of the theory of animal ecology developed by H.G. Andrewartha, L.C. Birch, T.O. Browning, D.A. Maelzer and their students. The classification of the environment given by H.G. Andrewartha in Introduction to the Study of Animal Populations (1971) is formalized, with the exclusion of the component ‘weather’. In addition, the notion due to D. A. Maelzer that certain objects ‘only modified the value of some resource or other component of environment’ is also formalized and extended. The class of malentities is enlarged to include the case of an animal eating a poisonous animal. This enlarged class includes some animals formally classified as ‘aggressors’. Symbiosis is also discussed.
The light‐brown apple moth, Epiphyas postvittana (Walker): 4. Studies on population dynamics and injuriousness to apples in the Australian Capital Territory
Authors: GEIER P. W. , BRIESE D. T. 
Published: July 2006

AbstractA population study of the light‐brown apple moth (LBAM), Epiphyas postvittana (Walker), was pursued from 1963–64 to 1966–67 in a naturally‐infested, unsprayed apple plantation near Canberra. The investigation covered the period of tree development leading up to and including, the production of the first substantial crop.The life history of LBAM and the occurrence of natural enemies were examined. The species did not produce seasonal series of identifiable generations, but individuals in all development stages tended to co‐exist as cohorts of uncertain generation status.Whereas numbers of LBAM decreased gradually from 1963–64 to 1965–66, they rose again markedly in 1966–67, following the release in the study area of about 3,000 laboratory‐reared moths. From periodic field surveys and complementary experiments, it was inferred that the population dynamics of LBAM in the study area consisted essentially in the production of excessive numbers of immature stages, which were reduced by natural enemies to much smaller cohorts of mature stages, determined by the ability of fruit trees to supply the LBAM's requisite food and shelter. It is argued that this ability, i.e. the carrying capacity for LBAM, decreased as the trees matured, and that the damage of LBAM in the crops of fully‐bearing trees would have been negligible under the conditions prevailing in the study area.The probability of damage to fruits was directly proportional to the numbers of larvae and of fruits present, indicating that, unlike codling moth for instance, LBAM did not seek out fruits for attack, but struck them by chance encounter.The results of this life‐system analysis are discussed in the light of Southwood & Comins’(1976) and Southwood's (1977a, b) generalizations on population dynamics, ecological strategies, and the status of pests. LBAM is believed to display all the characteristic features of an ‘intermediate strategist’ and an ‘intermediate pest’.
Productivity and nutrient content of Juncus kraussii in an estuarine marsh in south‐western Australia
Authors: CONGDON R. A. , McCOMB A. J. 
Published: July 2006

Abstract Juncus kraussii, which is the dominant emergent macrophyte in the marshes of the Blackwood River Estuary, has an estimated net above‐ground production there of 0.3 to 1.3 kg dry weight m‐2 yr‐1. A high standing crop of live culms is present throughout the year and dead material generally exceeds live. New culms are produced throughout the year, but especially during the warm season. Growth and senescence of culms also occurs throughout the year although there is evidence for increased growth in the warm season.Concentrations of nitrogen and phosphorus are given on a per g dry weight and per m2 basis. Some 60% of the nitrogen and 50% of the phosphorus remain in the dead culm material, the remainder being retranslocated. Sodium and, especially, potassium are readily retranslocated during senescence, but calcium and magnesium are much less mobile.
Species associations in a grassland on a heavy cracking clay soil in north‐west Queensland: their structure, soil associations and effects of flooding
Authors: HALL T. J. 
Published: July 2006

AbstractFour plant associations were separated on the basis of relative abundance of species in an ungrazed area of open grassland on a heavy cracking clay soil in north‐west Queensland. They were correlated with soil pH, exchangeable potassium, available phosphorus, moisture content and particle size. Two associations were characterized by Iseilema spp., Astrebla spp. and Cyperus spp. and two by Eulalia fulva and Dichanthium fecundum.Flooding caused a significant decline in the relative abundance of all major perennial grasses except Eulalia fulva, an increase in Cyperus spp., a reduction in legumes, establishment of previously unrecorded forbs, and a reduction in the basal cover of all associations. Heavy grazing by cattle prior to flooding increased the proporton of particular forbs, almost eliminated Astrebla squarrosa and resulted in a basal cover of 1.8% compared with 4.4% in an adjacent exclosure.
Partitioning of resources amongst seed‐harvesters in an ant community in semi‐arid Australia
Authors: BRIESE D. T. 
Published: July 2006

AbstractResource partitioning among five species of seed‐harvesting ants in a semi‐arid saltbush and adjacent grassland habitat of southwestern New South Wales is analysed. While habitat differences between species were only slight, the utilization of two resource dimensions, food type and time available for activity by them, varied markedly in response to environmental changes. The degree to which species overlapped in their use of these resources also fluctuated as conditions varied. Thus, both the manner and extent to which the harvester ant species interact is rapidly and continually changing in response to environmental fluctuations. The results suggest that, at most times, there is very little pressure due to exploitative competition within the harvester ant community.
Rainforest invasion onto Tasmanian old‐fields
Authors: READ JENNIFER , HILL ROBERTS 
Published: July 2006

AbstractThe regeneration of rainforest onto land cleared for grazing early this century was studied on several sites in northern Tasmania. Drimys lanceolata, a bird‐dispersed species, was the main invader. The climax forest species. Nothofagus cunninghamii and Atherosperma moschatum were invading slowly from the forest edge with occasional trees established in the field. Woody plants in the old‐field were clumped around logs. This was related to the role of logs in attracting seed and to possible roles as competition‐free sites and sites safe from browsing and climatic stresses. Changes in dominance by particular life forms appeared to be related to dispersal events, environmental modification by the developing vegetation and life history characteristics. The extremely slow invasion by climax species is due to the absence of bare mineral soil as well as to dispersal characteristics, browsing and possibly exposure to climatic stresses.
Microhabitat selection by two reptile ticks at their parapatric boundary
Authors: PETNEY T. N. , BULL C. M. 
Published: July 2006

AbstractThe parapatric boundary between the reptile ticks. Aponomma hydrosauri and Amblyomma 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, where Amb. limbatum is found, there is less litter and an absence of Eucalyptus leaves in the litter. Since the litter retards evaporative water loss, and Ap. hydrosauri is less tolerant of dehydration, reduced litter quantity may reduce the fitness of colonizing Ap. 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 fed Ap. hydrosauri larvae which, in trials with litter from north of the boundary, rarely moved from the bare soil. This behaviour may also reduce the fitness of colonizing Ap. hydrosauri.The two species adopted different positions in the litter. Ap. hydrosauri were predominantly found on the surface, at the interface between soil and litter as fed larvae, and on or under the surface as nymphs. Amb. limbatum larvae 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.
Small‐mammal recolonization of open‐forest following sand mining
Authors: FOX BARRY J. , FOX MARILYN D. 
Published: July 2006

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 in M. musculus biomass.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 in P. novaehollandiae biomass 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 to forest.
Detection of transoceanic migration of insects to a remote island in the Coral Sea, Willis Island
Authors: FARROW R. A. 
Published: July 2006

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 winds.
Influence of sampling strategy on the relationships between fauna and vegetation structure, plant lifeform and floristics
Authors: TAYLOR J. A. , FRIEND G. R. , DUDZIŃSKI M. L. 
Published: July 2006

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 strategies.
Flammable infructescences in Banksia: a fruit‐opening mechanism
Authors: LAMONT BYRON B. , COWLING RICHARD M. 
Published: July 2006

AbstractThere is a strong correlation between serotiny and persistent florets in the genus Banksia. Momentary application of flame is sufficient to ignite infructescences retaining a mantle of floral remnants and induce opening of most of the follicles. Prior removal of the florets or tests on species with deciduous florets resulted in no combustion and no follicle opening.
Vegetation and nesting preferences of black noddies at Masthead Island, Great Barrier Reef. II Patterns at the micro‐scale
Authors: HULSMAN K. , DALE P. , JAHNKE B. R. 
Published: July 2006

AbstractDistribution and abundance of black noddy Anous minutus nests in relation to vegetation were studied at Masthead Island, Great Barrier Reef. Methods used included mapping, correlation and regression analyses.Number of nests varied significantly with height and species of tree. Taller trees contained more nests per tree than did smatter trees. Most nests occurred in Pisonia but the highest nesting densities occurred in Ficus and Celtis. There were significant positive correlations between treephxsiognomy (d.b.h. etc.) and number of nests in Pisonia, Ficus and Celtis but noddies may avoid nesting in senile trees.Noddies preferred to nest in some species of tree rather than others, e.g. Ficus and Celtis were apparently preferred to Pisonia. The sparse fotiage of Ficus and Celtis may facilitate access of noddies to their nests and therefore be preferred to the more densely foliaged Pisonia.