bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of maize residues and tillage on emergence of Setaria faberi, Abutilon theophrasti, Amaranthus retroflexus and Chenopodium album
Authors: BUHLER D.D. , MESTER T.C. , KOHLER K.A. 
Published: July 2006

SummaryTillage and maize (Zea mays L.) residues at up to four times the base level had variable effects on the emergence of four annual weed species in the field. Environmental conditions varied during the three years of the research and interacted with residue and tillage to govern seedling emergence. When tillage affected Setaria faberi Herrm., emergence was greater in untillcd than tilled plots. The effect of residues varied among years. Abutilon theophrasti Medik, emergence from tilled soil was greater than from untilled soil in two of three years. Maize residue at two or four times the base levei reduced emergence. Amaranthus retroflexus L. emergence was often greater from untilled than tilled soil. The effect of maize residues on this species was dependent on tillage and precipitation. Chenopodium album L. emergence was affected by tillage and residues but differences over the three years were inconsistent. Results of this research indicate that tillage and residues interact with weed species, precipitation and other factors to regulate seedling emergence. The reduced soil disturbance and minimal weed seed burial associated with the elimination of tillage appear to have a greater impact on weed population dynamics than surface residues in non‐tillage maize production systems.
Gene flow within a population of the outbreeding Sinapis arvensis: isozyme analysis of half‐sib families
Authors: LEFOL E. , DANIELOU V. , FLEURY A. , DARMENCY H. 
Published: July 2006

SummaryProgeny of several Sinapis arvensis L. plants sampled in a field were analysed for isozyme patterns at two highly polymorphic loci: esterasc and acid phosphatase. Allele frequencies of pollen subpopulations that effectively fertilized each separate sampled plant were compared. In spite of self‐incompatibility, large variations in allele frequencies were shown among pollen subpopulations. Non‐random mating owing to gametic selection and plant density effects were evidenced and could reduce gene flow within a population,
Environment and food of the budgerigar Melopsittacus undulatus
Authors: WYNDHAM EDMUND 
Published: July 2006

AbstractBudgerigars range and breed over most of the interior of Australia. During a year, budgerigars may experience a maximal change in day length of about 5 h, and temperatures range from well below to above their zone of thermo‐neutrality. In the north of the budgerigar's range there is growth of pastures in summer and autumn and in the south there is growth in spring and early summer. In the arid interior, growth is irregular from year‐to‐year and varies from site‐to‐site. However, in northern arid regions growth tends to occur in summer and autumn; in southern arid regions in spring and early summer; and over most of the arid regions in most years there is some growth in run‐on areas.In inland mid‐eastern Australia budgerigars ate only seeds of ground vegetation. These seeds were from about 0.5 to 2.5 mm in length, weighed between about 0.3 and 1.3 mg and had an energy content of about 18.9 kJ g‐1. Ata site on Mitchell grass plains Astrebla spp. were the main seeds eaten. At a site further inland the diet was more diverse: in the hot months of 1973–74 they ate mainly Boerhavia diffusa, Atriplex spp. and Astrebla pectinata, during the cold months of 1974 mainly Iseilema and an unidentified seed, and in spring 1974 mainly Atriplex spp. There was no evidence of special dietary requirements for breeding; in particular no requirements of soft, unripened seed or insect food to feed young. Males and females, adults and juveniles, and individuals in the same flock had similar diets.Information from the literature and my data suggest there is considerable stability and seasonal regularity in the budgerigar's food supply.
The seasonal distribution and characteristics of bush fly Musca vetustissima Walker populations in south‐western Australia
Authors: MATTHIESSEN J. N. 
Published: July 2006

Abstract In the agricultural region of south‐western Australia the bush fly Musca ventustissima Walker was found to occur permanently in the north‐eastern half but it died out during winter in the south‐west. The abundance of bush flies increased rapidly throughout the overwintering zone in early spring as a result of local breeding. Flies then dispersed south‐westwards, completely repopulating the region during October. Immigrant flies were large and therefore highly fecund, and of advanced reproductive maturity. Local breeding then rapidly increased the population. Maximum abundance occurred in mid‐spring in the north and east and in early summer in the south and west. Abundance was greatest in the north where large overwintering populations occurred, and in the far south where repopulation occurred early in the seasonal cycle of pasture growth so that the more favourable cattle dung produced flies that were more fecund than their immigrant parents. The abundance of bush flies declined throughout the region in summer, to negligible levels near the south‐west coast but, paradoxically, higher levels occurred inland where there were fewer cattle. On average, flies were smaller and reproductively younger in summer. In areas where irrigated pastures produced more favourable dung in summer, the patterns of abundance and other characteristics of flies did not differ substantially from those in comparable non‐irrigated areas. The abundance and other characteristics of a bush fly population 10 km from a cattle‐grazing breeding site were similar to those at the site, indicating that constant dispersal is the basis of the bush fly's ubiquity.
Species richness in vascular vegetation of the West Head, New South Wales
Authors: RICE BARBARA , WESTOBY MARK 
Published: July 2006

AbstractWe present data on vascular plant species richness, at the 0.1 ha scale and below, of sclerophyll vegetation on infertile sandstone, and some neighbouring types, in a non‐mediterranean climate area of temperate, east coast Australia The vegetation of sandstone is richer in species than is that of a permanently wet swamp (18/0.1 ha) or of more fertile soils (36, s.d.‐ 2). On sandstone, woodlands on moderate benched slopes (77, s.d. = 9) are richer in species than are the scrubs found on skeletal (56, s.d.= 7) or impeded drainage (48, s.d.= 8) soils, and this difference appears in the species‐area curve from 100 m2 up. Species richness of the sandstone vegetation, like its growth‐form mix, is very similar to species richness of South African fynbos and southwestern Australian heath. which supports the idea that the community properties of this sort of vegetation are not determined by climate but are determined by soils. The strong contrast in species richness, noted by Naveh & Whittaker (1979), between the mediterranean‐climate vegetation of South Africa and southwestern Australia on the one hand, and California and Israel on the other, need not be attributed to different evolutionary histories of the floras. The present environment, in the form of the soil factor, could well be the main determinant.
A comparison of detrended correspondence analysis and principal co‐ordinates analysis using four sets of Tasmanian vegetation data
Authors: BROWN M. J. , RATKOWSKY D. A. , MINCHIN P. R. 
Published: July 2006

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 analysis.
The structure and floristic composition of the rainforest of the Liverpool Range, New South Wales, and its relationships with other Australian rainforests
Authors: FISHER H. J. 
Published: July 2006

AbstractThe rainforest of the Eiverpool Range (ca 32° S) consists of discrete stands ranging from 1 to 100 ha in area. Its distance from the coast (ca 160 km) results in a relatively low (for rainforest) average annual rainfall of approximately 900 mm. The rainforest is described quantitatively in terms of the relative importance of its component woody species. One hundred and fourteen vascular plant species were found and identified within the rainforest stands, including 37 tree and 16 shrub species. Daphnandra micrantha is the most common tree species in the stands, while Acmena smithii is locally dominant at higher elevations. Following Webb (1978), the Liverpool Range rainforest is described as a noto‐microphyll vine forest. Alternatively, portions of the forest that are at higher elevations represent warm temperate rainforest, while the portions at lower elevations are more subtropical in character, although the two intergrade. The Liverpool Range rainforest has substantial floristic affinity with the rainforests of the southern coast of New South Wales.
The effect of severe defoliation on the subsequent growth and development of five rangeland pasture grasses of south‐western Queensland
Authors: BROWN R. F. 
Published: July 2006

AbstractYoung plants of five arid zone grasses. Cenchrus ciliaris, Astrebla lappacea, Artstida armata, Thyridolepis mitchelliana, and Digitaria ammophila, were heavily defoliated and their subsequent regrowth and development monitored and compared with that of intact plants. Defoliation impaired the development of both roots and plant tops in all species. Regrowth was inconsistent with theories of assimilated reserves stored in roots to support regrowth. The species differed in their apportionment of assimilate between competing plant parts. The differences were similar in both intact and defoliated plants. Both C. ciliaris and A. lappacea maintained a large root mass but produced few inflorescences whereas A. armata and D. ammophila did the opposite. T. mitchelliana had an intermediate pattern of allocation. Both D. ammophila and A. armata resumed flowering soon after defoliation. The different reactions to defoliation are discussed in relation to historical deterioration in pasture condition which may be linked with the prolific seeding capacity of A. armata.
Mineralization of soil nitrogen in three forest communities from the New England region of New South Wales
Authors: RICHARDS B. N. , SMITH J. E. N. , WHITE G. J. , CHARLEY J. L. 
Published: July 2006

AbstractNitrogen (N) mineralization rates and the temperature response patterns of mineral N production in surface (0–7.6 cm) soils were compared in laboratory incubation studies based on disturbed, composite samples. Seasonal variation in the field levels of mineral N, and mineralization potential of intact (7.6 × 5.6 cm diameter) soil cores, were also investigated.Ammonification proceeded rapidly in each soil. Nitrification did not occur in grassy forest (GF) soil but was active in both layered forest (LF) and mossy forest (MF) soils, especially the former. Total mineral N production was greatest in MF and least in LF.Ammonification in disturbed samples was maximal at 50°C in all three soils with a secondary peak at 10°C in LF soil. Nitrification in LF and MF soils was most rapid at 25°C. Several species of ammonifying bacteria with different temperature optima were isolated, indicating that the process of ammonification is a composite of the activities of a variety of decomposer microbes.Mean field levels of mineral N and NH4–N throughout the year were greatest in MF and least in LF. Seasonal fluctuations in NH4–N were evident, concentrations being universally low in mid‐winter (about 1.5 μgg‐1), increasing to a maximum in late summer (about 5 μg g‐1 in LF: 16–18 μg g‐1 in GF and MF). Field levels of NO3–N were more constant and never more than 5 μg g‐1 in any community. Both total mineralization and ammonification in intact cores were greatest in MF and least in LF while nitrification was greatest in LF and almost negligible in GF, thus confirming the results obtained with disturbed samples. The potential for mineralization was large in mid‐winter when the amount of mineral N was very low, and small in late summer when field levels were higher: this is interpreted as indicating that seasonal climatic factors regulate the availability of substrates for decomposers.Spatial variability in field levels of mineral N and mineral N production in the laboratory was evidenced by significant ‘sampling site’ effects in each community: however, at the sampling intensity used, the presence of bark mounds around Eucalyptus saligna trees could not be shown to affect these attributes.The inability of GF soil to nitrify when incubated in the laboratory could not be ascribed to a high C/N ratio, low pH, lack of substrate ammonium, or a low population of autotrophic nitrifying bacteria. No attempt was made to investigate the presence of allelopathic nitrification inhibitors. No evidence was obtained to support the view that nitrification is atypical of climax communities in situ. The most productive forest (LF) had the greatest capacity to nitrify and the least productive community (GF) the smallest capacity to do so.
Population dynamics of the tropical annual grass Sorghum intrans in relation to local patchiness in its abundance
Authors: ANDREW M. H. 
Published: July 2006

AbstractCommunities of Sorghum intrans, a tropical annual grass of north‐west Australia, contain sparse patches several metres in diameter within otherwise dense swards. These patches are persistent for at least ca. 4 years, despite the fact that these species are annuals which lack a persistent seed‐bank.Three possible causes of the sparse patches were investigated at a site near Darwin: loss of viable seeds through granivory or death; high plant mortality; or poor fecundity. This was done by augmenting the seed‐banks of S. intrans in the sparse patches, and thinning stands of seedlings in the surrounding, naturally dense areas, and comparing the results of these perturbations with controls.Granivory did not appear to be a cause of the sparse patches. Furthermore, the seeds in the sparse patches did not become inviable over the dry season. Compared with the plants of S. intrans in the naturally high‐density areas, survival of the plants in the augmented patches was not reduced, but vigour and seed production were. Conversely, plants in the thinned stands had a higher survival rate and very much greater vigour and seed production than plants in either the undisturbed patches or the undisturbed surrounding areas. Biotic constraints to plant growth such as grazing and disease appeared to be unimportant.These sparse patches result from poor site potential for S. intrans which limits its growth and reproductive output.
The invasion of Kangaroo Island by alien plants
Authors: KLOOT P. M. 
Published: July 2006

AbstractThe numbers of alien plant species naturalized on Kangaroo Is., South Australia, at different times were examined and compared with those from an adjacent part of the mainland, the Encounter Bay area. The establishment of new species appears to have been accelerating and the rate of acquisition is around 50% faster on the mainland than on the island. Flinders’ Chase, a National Park at the western end of Kangaroo Is., has been acquiring alien species more slowly than the rest of the island. Land use patterns are a more effective barrier to the invasion of alien plants than a 15 km stretch of sea.
Soil chemical properties as related to forest succession in a highland area in north‐east Tasmania
Authors: ELLIS R. C. , GRALEY A. M. 
Published: July 2006

Abstract The relationship between vegetational type and a number of soil chemical factors was examined in secondary successions from fire‐maintained eucalypt/grass to climax rainforest communities growing on uniform granitic soil parent material. Canonical variates analysis, which utilized the following variables: pH; loss on ignition; total N, P, K, Ca, and Mg; cation exchange capacity and exchangeable Ca, K, and Mg; and potentially mineralizable N, revealed close overall similarity between surface soils of adjacent types, and significant differences among those of types distant from each other in the successional sequences. Exchangeable Ca, mineralizable N, total N. P, and Mg, and pH all differed significantly among soils of the vegetational types. However, the only identifiable gradients in soil properties that were detected within a successional sequence were in total and mineralizable N, which tended to increase, and pH, which generally tended to decrease with progression towards the climax vegetation. Nitrification was promoted by the presence of Acacia dealbata and apparently inhibited by the presence of Leptospermum lanigerum; it was more rapid in soils beneath late successional vegetation than in those from climax vegetation or early stages of succession, and was inhibited in soil from old (> 200 years) grassland. It was concluded that differences among soils in chemical composition and rates of mineralization of N were due to differences in species composition of the vegetational types that they carried for the time being.
Response of Callitris intratropica R.T. Baker & H.G. Smith to fire protection, Murgenella, Northern Australia
Authors: BOWMAN D. M. J. S. , WILSON B. A. , DAVIS G. W. 
Published: July 2006

AbstractPattern analysis of stems > 10 cm d.b.h. on 514 one‐tenth ha quadrats showed that Callitris intratropica has a clumped distribution throughout the more uniformly distributed Eucalyptus forests at Murgenella in Northwest Arnhem Land. Callitris clumps are typically located on sites with sandy soils. Eucalypts occur within Callitris clumps.Fire suppression over the past 18 years has allowed some C. intratropica to establish on Eucalyptus forest sites with fine textured soils It is argued that distribution of Callitris preceding fire management was controlled by the interactive effects of fire, soils and understorey vegetation. High grass fuel loads (and thus intense fires), and competition are thought to have previously limited establishment of C intratropica on fine textured soils. Early dry season burning by Aboriginals may also have been important in limiting fire intensities and accumulation of fuel in Callitris stands. Dry electrical storms commonly cause fires prior to the summer rains. Such wildfires did not completely kill stands of Callitris saplings or trees at Murgenella. Survivors were found to be significantly bigger and to have thicker bark than the dead stems. Sapling size is related to age and density, thus fire may be an important mechanism in thinning heavily stocked stands.The continuous regeneration of Callitris and Eucalyptus is in marked contrast to the inhibition of Pinus caribaea recruitment following fire protection in the monsoonal neotropics. The lack of seral tree species in northern Australia suggests an equilibrium between forest distribution and the physical environment.
Modelling development of larvae and pupae of Pterohelaeus darlingensis Carter with Podolsky phenocurves
Authors: ALLSOPP P. G. 
Published: July 2006

AbstractPodolsky phenocurves were constructed to model the development of larvae and pupae of Pterohelaeus darlingensis under fluctuating temperatures. The models lny =9.90 — 1.78lnx and lny = 8.71 — 1.93lnx give the best estimates for larval and pupal development, respectively. These models are shown to be inferior to those derived with the DEVAR program for modelling development in fluctuating temperatures.
Soil of the nest‐mound of the seed‐dispersing ant, Aphaenogaster longiceps, enhances seedling growth
Authors: ANDERSEN ALAN N. 
Published: July 2006

AbstractAlthough a major benefit of myrmecochory in the Australian environment is believed to be the targeting of seeds to nutrient‐enriched ant nests, there is very little direct evidence for this. Here I report that, compared to control soil, soil from nest mounds of Aphaenogaster longiceps enhances the growth of seedling roots and shoots by about 50% in glasshouse trials. This benefit of nutrient‐enrichment, however, probably only occurs when seeds are dispersed by ants that construct large, long‐lived, nest mounds. This is very often not the case, and there is now increasing evidence that distance dispersal is often the major benefit of myrmecochory in Australia.
Rattus colletti (Rodentia: Muridae) in the Australian wet‐dry tropics: Seasonal habitat preferences, population dynamics and the effects of buffalo (Bubalus bubalis)
Authors: FRIEND G. R. , DUDZINSKI M. L. , CELLIER K. M. 
Published: July 2006

AbstractPopulation dynamics and habitat preferences of the dusky rat, Rattus colletti, were examined in the seasonal wetlands of the South Alligator River. Northern Territory, between late 1979 and 1982. Demographically, the species is characterized by short‐term seasonal shifts between habitats superimposed on a longer‐term irregular pattern of prolonged breeding and population irruption, followed by periods of relative rarity. These patterns are determined by the train of climatic events. The flexible life history strategy and movement patterns of R. colletti reflect fine‐scale adaptation to a climatic regimen which is markedly seasonal, but also highly variable between years in the amount and temporal patterning of rainfall.The distribution of R. colletti amongst vegetation types is influenced by two sets of environmental factors, both reflecting a gradient in elevation, soil type and vegetation. The primary factors are vegetative cover and height, and the extent and duration of flooding; the secondary set comprises buffalo‐induced features such as the degree of pugging and grazing. These factors are interrelated, and their relative importance to R. colletti varies greatly between seasons.Feral buffalo appear to exacerbate the harsh effects of the wet and dry seasons. The removal of these animals may ameliorate environmental conditions considerably, both temporally and spatially, resulting m generally higher, more stable and spatially less variable populations of R. colletti.
Size distribution and coning behaviour of the Australian cycad Lepidozamia peroffskyana
Authors: ORNDUFF ROBERT 
Published: July 2006

AbstractLeaf numbers as an estimate of sexual maturity and presence of current and previous season's cones were determined for individuals sampled in two populations of Lepidozamia peroffskyana near Dorrigo and Sealy Lookout, New South Wales, Australia. Average leaf numbers of known males and females were not significantly different. Average leaf numbers of plants showing no evidence of coning were lower than for coning individuals, suggesting that both populations contain substantial numbers of immature plants. About half the plants in both populations were putatively mature, but only 12% of such individuals in the Dorrigo population bore current season's cones compared with 51% in the Lookout population; 28% of the Dorrigo plants and 5% of the Lookout plants showed evidence of prior coning. Thus, in each population, not all mature plants produce cones during a given reproductive episode. The proportion that does so appears to vary from year to year. Cone production by individuals of each sex appears to be separated by several‐year intervals. The few plants with current season's cones in the Dorrigo population prevented determining a phenotypic sex ratio there, but for the Lookout population it was not statistically different from 1:1 male:female. The weevil Tranes lyterioides was abundant on two male cones that were entering the pollination phase in the Lookout population, suggesting that it may be involved in the pollination of this cycad.