bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reproductive allocation in a gender dimorphic shrub: anomalous female investment in Gynatrix pulchella?
Authors: LEIGH ANDREA , COSGROVE MEREDITH J. , NICOTRA ADRIENNE B. 
Published: July 2006

Summary

In gender dimorphic species, reproductive allocation (RA, the ratio of reproductive to vegetative biomass) is predicted to be greater in female plants than in male plants. Empirical research on dimorphic plant species supports this hypothesis. To date, of 44 dimorphic angiosperms for which RA has been reported in the literature, RA is greater in females than males in 40 species, is equal in four, and in no species is it greater in males.
In many instances where differential RA occurs, sexual dimorphism in morphological or physiological traits has been reported. This dimorphism is often attributed to the differing costs of reproduction or to selection to counteract such costs.
We investigated RA and other morphological and physiological characters in Gynatrix pulchella, a dimorphic species that we found ranges from dioecious to subdioecious or gynodioecious, depending on season and locality. Our results showed that contrary to our predictions functionally male plants allocated significantly more biomass to reproduction than female plants across three populations. Greater male RA was due to a combination of larger, more numerous flowers and lower leaf biomass per branch than females.
There were no detectable costs of greater RA in males in terms of decreased overall growth or increased mortality. Additionally, leaf nitrogen content was greater in males than in females and there were no between‐sex differences in gas exchange.
The finding that male plants allocate significantly more resources to reproduction than females in G. pulchella is apparently a unique case. However, equivalent RA for the sexes does occur in gynodioecious species and we suggest that higher male RA in gynodioecious plants may be more common than predictions based on sexual systems involving pure males.
Our results challenge accepted theory that allocation to reproduction should be greater in female plants than in males. In light of these findings, predictions regarding which sex should allocate more to reproduction need to be revised to accommodate the diversity of plant sexual systems.
On the effectiveness of higher taxonomic ranks for vegetation analysis
Authors: DALE M. B. , CLIFFORD H. T. 
Published: July 2006

AbstractThe ecological value of employing taxonomic categories other than species to describe vegetation is examined by comparing the results of numerical classification. Using presence data only and an unsophisticated classification method with data from a small area, it is found that the use of generic and subgeneric categories instead of species causes little loss in interpretability. At the family and subfamily levels more sophisticated analyses probably employing quantitative data, are apparently required to achieve similar levels of interpretability. The transformation between categories is shown to be a simple matrix multiplication and some alternative transformations are briefly outlined. It is suggested that the use of different taxonomic categories in a sequence of analyses beginning with the highest category would provide a useful means of planning which could reduce the overall time required for the analysis of large data sets.
The effect of prescribed burning on the soil fauna and on litter decomposition in Western Australian forests
Authors: SPRINGETT JOSEPHINE A. 
Published: July 2006

AbstractThe effect of mild fires on the soil fauna was examined in a Pinus pinaster plantation and in Jarrah (Eucalyptus marginata) and Karri (E. diversicolor) forests. In the pine plantation, litter decomposition ceases until four years after burning. In both native forests, species diversity and density are reduced after burning and do not recover their pre‐burning values during a normal prescribed burning rotation. Prescribed burning on a five to seven year rotation is likely to permanently simplify the litter fauna and flora, with far‐reaching effects on forest and hygiene.
A photographic method and a ranking procedure for estimating numbers of the rose aphid, Macrosiphum rosae (L.), on rose buds
Authors: Maelzer D. A. 
Published: July 2006

AbstractTwo sampling methods for aphids are described. The first is a photographic method that allows sampling with replacement for use in field experiments and in which a linear regression technique is used to estimate the errors of sampling. The second method is a ranking procedure for sampling natural populations in which regressions of aphid numbers on ‘colony length’ are used to minimize bias.
Sequential decision plans for the management of cotton arthropods in south‐east Queensland
Authors: STERLING WINFIELD L. 
Published: July 2006

AbstractAn outline of a pest management plan for cotton insects has been developed that is essentially based on three sets of sequential sampling plans. These plans utilize the binomial sampling theory and treatment levels for pests during three phenological stages of cotton plant growth. The plans also provide a known level of accuracy in making management decisions and frequently will require less time than other sampling techniques.
Host specificity of insects in a community of three co‐dominant Eucalyptus species
Authors: MORROW P. A. 
Published: July 2006

AbstractIn a subalpine association of three Eucalyptus species, phytophagous insects showed strong host preferences even among very closely related Eucalyptus species. Sixty‐three per cent of insect species attacked only one eucalypt species, 30% attacked two species and only 8% fed on all three. Ninety‐seven per cent of individuals belonged to species using one or two hosts. The results are discussed in relation to the degree of host specificity that might be expected when most potential hosts are members of a single genus, the way in which host specificity is determined, and the potential of insects with host preferences to affect the dynamics of plant communities.
The Macquarie perch, Macquria australasica (Pisces: Percichthyidae), of Lake Eildon, Victoria
Authors: CADWALLADER P. L. , ROGAN P. L. 
Published: July 2006

AbstractThe results of a field study carried out between 1966 and 1969 indicate that the spawning migrations of Macquarie perch, Macquaria australasica, from Lake Eildon, Victoria, into the inflowing Delatite, Howqua, Jamieson, Goulburn and Big Rivers occurred when water temperatures in the rivers reached 16.5°C. Because of different temperature regimes the times of the spawning migration and spawning differed from river to river. Migrating fish were of a uniform size and were in their fifth to tenth years of life. Recaptures of tagged fish suggest that some fish use the same river each year for spawning. Observations on pre‐spawning and spawning behaviour and on the characteristics of the spawning site are recorded. Fecundity of fourteen fish in the size range 305–405 mm standard length varied from 50189 to 107 724 eggs per fish. The virtual disappearance of Macquarie pereh from Lake Eildon was probably caused by a combination of several factors, including changed habitat, overfishing of the spawning stock and predation by, and competition for food with, introduced fish.
The ecology of Araucaria species in New Guinea. II. Pattern in the distribution of young and mature individuals and light requirements of seedlings.
Authors: ENRIGHT N. J. 
Published: July 2006

Abstract Conventional pattern analysis and segregation analysis were used to investigate the hypothesis that young and mature individuals of Araucaria hunsteinii were not usually found growing in close association whilst the distribution of young and mature individuals of A. cunninghamii was essentially random. It was considered that this pattern reflected a difference in regeneration strategy between the two species, A. hunsteinii being a gap regenerator and A. cunninghamii a shade‐tolerant species. A seedling growth‐experiment using three different shade treatments and four temperature treatments tested this hypothesis further. Results show that A. hunsteinii is more dependent on high light intensity than A. cunninghamii for the production of biomass. A. cunninghamii produces more biomass than A. hunsteinii under all treatment conditions.
Litter fall and nutrient cycling in karri (Eucalyptus diversicolor F. Muell.) forest in relation to stand age
Authors: O'CONNELL A. M. , MENAGÉ P. M. A. 
Published: July 2006

AbstractAnnual litter fall, nutrient concentrations in litter components and annual weight of nutrients in litter fall have been estimated for karri forest stands aged 2, 6, 9 and 40 years and in mature forest. The weight of litter falling annually increases with stand age, ranging from 1.13 t/ha in 2‐year‐otd regeneration to 9.45 t/ha in mature forest. This increase is due mainly to greater amounts of twigs, bark and fruit falling in older stands. Leaf fait is relatively independent of stand age once the canopy of regenerating stands closes and the understorey has developed.Concentrations of N, P, K, S and Mn in karri leaf litter differ significantly between sites and the differences appear to be related to stand age. Highest levels of these elements are found in karri leaf litter from the youngest stand and the concentrations decrease with increasing stand age. The amounts of annual litter fall and of nutrients cycling in litter are among the largest reported for Australian forests. In particular cycling of Ca, K and Mg in mature karri forest is greater than has been reported for any other eucalypt forest. Karri forest understorey plays a key rote in nutrient cycling in these ecosystems, contributing 30–70% of the weight of many of the nutrients in the leaf component of titter. Understorey leaf material is particularly important in the cycling of N, S and the micro‐nutrients Cu and Zn.
A new approach to the species classification problem in floristic analysis
Authors: AUSTIN M. P. , BELBIN L. 
Published: July 2006

AbstractA new method of species (inverse) classification of vegetation data, i.e. classification of species into groups with similar ecological tolerances, is presented which overcomes the problems of species abundance distorting the results. The algorithm TWO‐STEP is based on the use of an asymmetric measure of dissimilarity:
image
where i, j are species, h is the stand, n is the total number of stands, and xih is the amount of species i in stand h.The algorithm uses the rows of the asymmetric dissimilarity matrix generated as above to form a second symmetric dissimilarity matrix using the measure:
image
where m is the number of species and k the species.Flexible sorting is applied to generate a species classification. Comparison of results after applying the TWO‐STEP algorithm and a standard alternative to an artificial data set demonstrates its efficacy. TWO‐STEP also shows considerable advantages over previous analyses for a Queensland rainforest data set (quantitative) and an English heath (qualitative) data set. Normalization of species data appears advantageous for quantitative data only.
Modelling the lineage of a growing population as an age‐dependent branching process
Authors: WOODWARD IAN O. 
Published: July 2006

AbstractA new model for population growth as a branching process is described. It requires knowledge of the population's age‐specific survivorship and fecundity curves. The total population size at any time is calculated by summing across all branches of the tree representing the population's lineage and thus the model also allows the lineage of the developing population to be traced. Use of the model is demonstrated by a hypothetical example. The model could be of particular value in tracing the phylogenetic development of populations and/or species.
Does Araucaria hunsteinii compete with its neighbours?
Authors: ENRIGHT N. J. 
Published: July 2006

Abstract A comparison of the proportion of total stand basal area contributed by Araucaria hunsteinii, as opposed to the rest of the forest, in a number of 0.5 ha plots from New Guinea rainforest is presented. Results suggest that A. hunsteinii avoids competition with other tree species. Several hypotheses which may explain this phenomenon are advanced.
Do waxes on Eucalyptus leaves provide protection from grazing insects?
Authors: EDWARDS PENELOPE B. 
Published: July 2006

AbstractEvidence is presented which indicates that the removable wax layer on juvenile leaves of several species of Encalyptus provides protection from grazing by the Eucalyptus tortoise beetle, Paropsis charybdis, by preventing the adult beetles from gaining a foothold. Other possible roles of Eucalyptus leaf waxes, particuarly those related to frost resistance, are considered in the light of the present observations.
Short Note Simpson Desert dunecrest assemblages
Authors: BUCKLEY R. 
Published: July 2006

AbstractThere are two distinct plant assemblages on the dunecrests of the Simpson Desert. The first is characterized by Zygochloa paradoxa and Chamaesyce wheeled. The second is marked by the presence of Calotis erinacea and Helichrysum ambiguum. There are no consistent differences in texture or fertility between the soils occupied by these four species on the sandridges though there are some differences in other habitats. Hence static soil differences cannot account for the distribution of the two assemblages. It is suggested that the Calotis patches represent populations spread from focal plants established after the 1960s drought, but this remains untested.
An energy and water budget for a population of the arid zone scorpion Urodacus yaschenkoi (Birula 1903)
Authors: MARPLES T. G. , SHORTHOUSE D. J. 
Published: July 2006

AbstractA population energy budget and water relations of the arid zone scorpion Urodacus yaschenkoi (Birula 1903) is described. The standing crop varied between 1945 and 4043 kJ in 2240 m2. The annual population respiration was 191 l of oxygen or 3562 kJ. Ecological efficiencies using laboratory and field measurements of energy flow were calculated for each instar. Water loss was extrapolated from laboratory studies and was shown to be more critical to the survival of the population than energy demand.
Catastrophic disturbance and vegetation on Little Slope, Lord Howe Island
Authors: PICKARD JOHN 
Published: July 2006

AbstractLittle Slope is a series of debris avalanche deposits below basalt cliffs 700 m high at the southern end of Lord Howe Island (31°35′S 159°05′E). There are five distinct physiographic areas on the slope, each separated by sharp boundaries which mostly correspond to boundaries between features on the cliffs above. The physiography is a consequence of a series of landslides of different, but unknown, ages. A model of the physiographic history is presented. Each physiographic area supports a different vegetation community, also separated by sharp boundaries. The present structure of two communities, Melaleuca howeana scrub and Howea forsterana forest, is a consequence of damage by feral animals. Melaleuca scrub has replaced Cyperus lucidus sedgeland destroyed by goats (Capra hircus) browsing from 1914 until their extermination in 1955. Howea forest has a markedly unimodal age distribution with very few small individuals of the dominant palms. This is a result of the combined effects of browsing by goats on small palms, and seed predation by black rats (Rattus rattus) from the 1920s, preventing regeneration.Unless rat numbers are periodically reduced to reduce seed predation, regeneration may be insufficient to guarantee long‐term survival of the forest.
Soils and vegetation of central Australian sandridges. IV. Soils.
Authors: BUCKLEY R. C. 
Published: July 2006

AbstractCatenary patterns on central Australian sandridges are assessed for the following soil parameters: sand depth, texture, mobility and penetrability; moisture content and characteristic; organic C content, total N and extractable P, K and Ca. There are marked dune‐swale gradients in sand depth, soil texture, mobility and penetrability, moisture content at — 15 kPa, and N and organic C contents. There are dune‐swale gradients in soil Ca content at a few sites only. Soil P shows significant heterogeneity but no catenary patterns, whilst K levels are homogeneous throughout. S, Mg, Fe, Mn, Cu, Zn, B, Mo, Co and CI were also measured for a number of sandridge soils but showed no significant catenary patterns and were therefore not studied in detail.
Viable soil seed banks in disturbed lowland tropical rainforest sites in North Queensland
Authors: HOPKINS MIKE S. , GRAHAM ANDREW W. 
Published: July 2006

Abstract Four 0.125 m2 soil samples, 50 mm deep, from each of eight tropical lowland rainforest sites ranging from primary and secondary forests to degraded Imperata grasslands were exposed to shade‐house conditions. Germinations of soil seeds were monitored over 28 weeks in April‐October. The viable seed banks in the primary forest (592 m‐2) and the secondary forest sites resulting from one cycle of clearing and abandonment (1300–1400 m‐2) were composed predominantly of secondary species. The viable seed banks were small in Imperata grassland sites that had been burnt regularly (200–400 m‐2) and very large (2000–3000 m‐2) in sites that had not been burnt for five years or more. The seed banks of the burnt and unburnt Imperata grassland sites were composed mostly of agricultural weeds whilst seeds of secondary rainforest trees were rare or absent. Similarities between the species composition of soil seed banks and regrowth vegetation types suggest that soil seed composition is important in determining the initial floristic composition following disturbance and that lack of seed of secondary rainforest trees is one factor which restricts re‐growth and secondary succession on degraded Imperata grasslands. Species such as Eucalyptus intermedia R. T. Bak., E. pellita F. Muell. and Imperata cylindrica (L.)Beauv. which can establish and deflect the normal rainforest secondary succession were not present in the soil seed bank, and these species appear to rely on fresh seed inputs, lignotubers or rhizomes to colonize and regenerate after disturbance.
Interactions between seedlings of Chrysanthemoides monilifera and Acacia longifolia
Authors: WEISS P. W. , NOBLE I. R. 
Published: July 2006

Abstract Displacement of Acacia longifolia on coastal dunes in New South Wales by the invasive species Chrysanthemoides monilifera may be linked to the greater competitiveness by the latter in the seedling stage, as demonstrated in pot experiments. This occurs despite a lower chlorophyll concentration in shoots of C. monilifera which leads to a lower assimilation rate per unit leaf area and lower carbohydrate concentrations. However, this assimilate is spread over a greater total leaf area. Such a strategy associated with‘quantity’may thus be more important than leaf‘quality’in terms of competitiveness. In A. longifolia, the production of higher quality‘leaves’but of lower total area may be well‐suited in the often sparse native populations found in sand dunes, but appears disadvantageous when seedlings of C. monilifera also co‐exist. The competitive advantage of C. monilifera over A. longifolia is reduced but not reversed under water stress. Under severe stress, mortality of C. monilifera is greater than that of A. longifolia in monocultures but mortality of both species is similar in mixtures. The reason appears to be that C. monilifera transpires more water per plant even though its rate of transpiration per unit leaf area is reduced under water stress because of early stomatal closure. In mixtures, faster root growth of C. monilifera ensures faster uptake of the available soil water, thus minimizing the inherent advantage in A. longifolia of its lower water use and greater efficiency.
Variation between field and laboratory populations of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)
Authors: WHITE G. G. 
Published: July 2006

Abstract Rates of development and pupal weights were compared between seven field populations and two laboratory strains of Tribolium castaneum. Rates of development did not differ significantly between field populations, but pupal weights did vary. Laboratory strains were both slower to develop and heavier than the field populations. The data support the hypothesis that field populations undergo selection for fast development in transient habitats. The findings are discussed in the context of r and K selection in field populations and laboratory cultures.
Breeding of the bush fly, Musca vetustissima Walker, in an over‐wintering area during winter and spring
Authors: MATTHIESSEN J. N. 
Published: July 2006

AbstractField experiments in an area of south‐western Australia where bush fly (Musca vetustissima) adults occur permanently, showed that it overwintered by continuous breeding; but only two to three generations occurred between June and September. Low survival of eggs and larvae in the food (cattle dung) from May to August was associated with rainfall rather than low temperatures. High egg‐adult survival occurred in late August; lower egg and larval survival in September and early October was attributed partly to dung fauna. Egg and larval survival was high in late October until December but predation or parasitization caused low survival of puparia outside the dung. Experimental and wild adult flies were largest and therefore most fecund in early spring; smaller wild flies in late spring appeared to result from larval competition for food. Simultaneous high egg‐adult survival, high fecundity and rapidly decreasing generation times in late winter and early spring provide a basis for explaining the major increase in adult bush fly abundance observed in some areas in mid‐spring.
Biomass and nutrient distribution in eucalypt plantations growing on rehabilitated bauxite mines
Authors: WARD S. C. , PICKERSGILL G. E. 
Published: July 2006

AbstractThe quantities of above ground biomass and nutrients accumulated by two eucalypt forests growing on rehabilitated bauxite mines in south‐western Western Australia were determined. The plantation at one site was 7.5 years old and had no understorey. The plantation at the second site was 3.5 years old and had been sown with seed of leguminous understorey species, resulting in a dense understorey.Similar amounts of biomass had accumulated at the two sites. However, the second site, in which the legume understorey accounted for 67% of the total above ground biomass, had about three times as much nitrogen in its biomass as the site without an understorey. There was also more sulphur in the biomass at this site. There were similar amounts of other nutrients at both sites.The plantation with an understorey is considered more likely to develop into a forest similar to the eucalypt forest prior to mining than the plantation without an understorey.
A biogeoclimatic analysis of Nothofagus cunninghamii (Hook.) Oerst. in southeastern Australia
Authors: BUSBY JOHN R. 
Published: July 2006

AbstractThe geographical limits of Nothofagus cunninghamii are highly correlated with climate and appear to be more or less in equilibrium with the climate of the present century in all but one of the areas of its present range. It is suggested that suitable climates for the species occur in the highlands of northeastern Victoria and southern New South Wales, beyond its present range, and it is possible that it occurred within the predicted area prior to the last ice age. It is suggested that populations of N. cunninghamii along the northeastern edge of its present range in the Central Highlands of Victoria may be migrating northeast along a narrow corridor of apparently suitable climate to re‐occupy the postulated former range. The rate of migration would be expected to be extremely slow because of the poor dispersal ability of the species and the adverse impact of recurrent fires.