bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of water temperature on the functional response of the water stick insect Ranatra dispar (Heteroptera: Nepidae)
Authors: BAILEY P. C. E.
Published: July 2006

Functional response curves were constructed for adult Ranatra dispar feeding on four different densities of notonectid prey at 15, 20, 25 and 30°C. Values for the attack‐rate and handling time were estimated from Roger's random predator equation. The most generally applicable response was the type II, with the mean number of prey eaten increasing with increase in temperature. The attack‐rate was linearly related to temperature while handling time decreased exponentially with increase in temperature, although values changed very little between 20 and 30°C. It is suggested that changes in metabolic activity and related ‘hunger’ effects on various components of predatory behaviour account for the observed number of prey eaten up to 25°C, however, an increase in the level of prey activity at 30°C may influence the observed number of prey caught (and eaten) at this higher temperature.
Bills and tongues of nectar‐feeding birds: A review of morphology, function and performance, with intercontinental comparisons
Authors: PATON D. C. , COLLINS B. G.
Published: July 2006

The bills and tongues of nectar‐feeding birds differ from continent to continent. The major differences are that: (i) the tongues of A Australian honeyeaters are broader any more fimbricated at the tip than the bifurcated tongues of sunbirds and hummingbirds; (ii) the bills of hummingbirds are more uniformly narrow and taper less markedly towards their tips than those of sun‐birds and honeyeaters; and (iii) bill curvatures are generally greater for sunbirds and honey‐creepers than for hummingbirds. A variety of hummingbirds has straight or even slightly upturned bills, while bills for all sunbirds, honeycreepers and honeyeaters are decurved to some extent. Despite differences in tongue morphology, hummingbirds, sunbirds and honeyeaters extract nectar at a similar range of rates, averaging approximately 40 γL s−1 from ad libitum feeders, and 1–15 γL−1 from flowers. All tongues collect nectar by capillarity, with licking rates of 6–17 s−1. Licking behaviour has been little studied, although speeds of licking respond to changes in sugar concentration and corolla length. The tongues of honeyeaters are broad, and may need to be brush‐tipped in order to allow capillary collection of nectar. Brush‐tipped tongues can cover large surface areas on each lick, and may allow honeyeaters to exploit nectar and honeydew that is thinly spread over large surface areas. Bill lengths of nectarivorous birds are similar in all regions, though species of hummingbird have the shortest and longest bills. Bill lengths largely determine the range of floral lengths that can be legitimately probed. Maximum floral lengths exceed bill lengths, since hummingbirds, sunbirds and honeyeaters protrude their tongues beyond the tips of their bills. Rates of nectar extraction, however, decline rapidly once the floral length exceeds bill length. Decurved bills may have evolved in honeyeaters and sunbirds to enable perching birds to reach flowers at the ends of branches more easily. Consistent differences in bill length between the sexes suggest that males and females may exploit different floral resources or different proportions of the same resources. For honeyeaters and sunbirds, males have longer bills than females, but the reverse is true for many hummingbirds.
Effects of multiple disturbance on macroinvertebrate communities in the Acheron River, Victoria
Authors: LAKE P. S. , DOEG T. J. , MARCHANT R.
Published: July 2006

In the Acheron River, southern Victoria, patches of riffle substratum (ca 1 m2) were disturbed every 10 days by kicking and raking. After 20 days, i.e. three disturbances, a further set of patches was disturbed once. For the next 70 days macroinvertebrate dynamics were monitored in the two sets of disturbed patches and also in contiguous control patches. There were no differences in the temporal changes in total species richness, number of species per sample, densities of individuals, or species diversity (H’) between the two disturbance regimes. The composition of the fauna colonizing each disturbance regime was similar, and after 33 days the number of species per sample was similar in disturbed and control patches. The fauna appears to be well adapted to physical disturbance and current ideas linking species richness and disturbance cannot be readily applied to stream communities at the temporal and spatial scales of this experiment.
The size and composition of soil seed‐banks in remnant patches of three structural rainforest types in North Queensland
Authors: HOPKINS M. S. , TRACEY J. G. , GRAHAM A. W.
Published: July 2006

The size and species composition of the soil seed‐bank in a remnant patch of each of three structurally and floristically distinct rainforests (Complex Mesophyll Vine Forest, Complex Notophyll Vine Forest and Semi‐Evergreen Vine Thicket) were assessed. Seeds of 94 species germinated from 12 surface soil samples collected from each site. All three seed‐banks were composed mostly of herbs characteristic of roadsides and agricultural land, and pioneer rainforest trees and shrubs. Agglomerative classifications indicated that the seed‐bank samples from each rainforest remnant had a characteristic species composition and could be distinguished reliably from seed‐bank samples drawn from other sites. Seeds of species present in the standing forest were poorly represented in the seed‐banks except for one long‐lived pioneer tree, Dendrocnide photinophylla, at one site. The seed‐bank from the seasonally dry vine thicket was significantly larger (4000 seeds m‐2) than those from the two moister sites (400–600 seeds m‐2, contained more seeds of roadside and agricultural herbs, and fewer seeds of rainforest pioneer and secondary shrubs and trees. We suggest three explanations for the different seed‐bank structure observed in the seasonally dry forest site. First, with increased deciduousness in rainforests, seed‐banks are increasingly subject to invasion and domination by seeds of rapidly maturing herbs. Second, long‐lived seeds that germinate in canopy gaps would be less likely to accumulate under deciduous forests because they would he exposed annually to conditions suitable for germination. Third, chronic disturbance by cattle and pigs produces sites suitable for the establishment of rapidly maturing herbs, and possibly disperses their seeds into the forest.
Dieback of rural eucalypts: the effect of stress on the nutritional quality of foliage
Authors: LANDSBERG JILL
Published: July 2006

Canopy dieback of Eucalyptus blakelyi trees is often associated with defoliation by insects: the foliage of trees with dieback is nutritionally superior for insects and is more heavily damaged by them. I investigated whether differences in the nutritional quality of foliage were genetically determined, or caused by environmental stress. In a series of glasshouse experiments, with seedlings and grafted plants derived from dieback and healthy populations of trees. I tested the influence of deprivation of nutrients, drought, waterlogging, saline waterlogging and addition of excess phosphate, on the nutritional quality of foliage. Differences in the foliar properties of plants from different genetic sources were not consistent with the differences between the source populations. Most of the environmental stresses applied caused a reduction in foliar quality (decreased water and nitrogen contents, and increased specific leaf weights). I hypothesize that the enhanced nutritional quality of the foliage of dieback trees is more likely to be a consequence of benign growing conditions (e.g. improved soil fertility) than of environmental stress. Field data for soil properties and the effect of drought on mature trees are consistent with this view.
Seasonal variation in honeyeater foraging behaviour, infloresence abundance and fruit set in Banksia spinulosa (Proteaceae)
Authors: VAUGHTON GLENDA
Published: July 2006

Seasonal variation in the foraging behaviour of honeyeaters and the production of fruit were examined in relation to the flowering intensity of Banksia spinulosa over two flowering seasons. The abundance of inflorescences was greater in the mid than in the early and late periods of the flowering season. In the mid period, many plants were blooming and each plant had many flowering inflorescences. Inflorescences received most visits by honeyeaters in the early flowering period; the visitation rate declining as flowering progressed. Eastern spinebills were the most common floral visitors at all times during the season. The number of foraging probes made at inflorescences by eastern spinebills did not differ throughout the season. Foraging movements between inflorescences on the same plant were more frequent in the mid period than in the early and late periods. Long distance movements between plants (more than 10 m apart) were promoted by aggressive interactions between honeyeaters. Inflorescences flowering in the late period were less likely to develop follicles because there were fewer visits by birds and/or because resources had been allocated to inflorescences pollinated earlier in the season. The number of follicles produced per infructescence did not differ between flowering periods. Overall, the number of inflorescences produced per plant, the number of visits received per inflorescence and the proportion of inflorescences that developed follicles were greater in 1987 than in 1988.
The use of open burrows to estimate abundances of intertidal estuarine crabs
Authors: WARREN J. H.
Published: July 2006

Estimation of absolute (or true) abundances of intertidal burrowing crabs is a difficult problem in some estuarine habitats because the nature of the substratum and behaviour of crabs can restrict researchers to the use of sampling methods which at best estimate only apparent, or relative, abundances. One method that has been used is to count open burrows to estimate population densities. This paper discusses the results of a test examining the validity of using burrows to estimate apparent abundances of a temperate ocypodid crab, Heloecius cordiformis. inhabiting mangrove forests of south‐eastern Australia. Under appropriate circumstances, this method may provide a quick and reliable estimate of abundance of crabs.
Methods for measuring amounts of energy available from banksia inflorescences
Authors: ARMSTRONG DOUG P. , PATON DAVID C.
Published: July 2006

Several methods have been used to remove nectar from banksia inflorescences to measure amounts of energy available, but these methods have been poorly described in the literature. Each method has advantages and disadvantages with respect to the proportion of nectar removed and the time taken to remove nectar. Power‐driven aspirators probably remove the most nectar, followed by syringes and capillary tubes. However, it often takes more than 20 min to sample an inflorescence using these methods. Centrifuging inflorescences by placing them in plastic bags and swinging them by hand on a rope takes only about 5 min anil allows many more inflorescences to be sampled per time. Centrifuging. however, removes only about 70% of the nectar so that the benefits gained by faster sampling are countered by reduction in accuracy. Nevertheless, amounts of nectar extracted by centrifuging provide a reliable index of the amounts present, and so it is possible to make Qualitative comparisons of inflorescences sampled at different times, from different locations, or from different experimental treatments.
Linear oceanographic features: A focus for research on recruitment processes
Authors: KINGSFORD M. J.
Published: July 2006

The early life of reef‐associated organisms is generally spent in the plankton. Recent evidence suggests that oceanographic processes have an important influence on the fate of early developmental forms; a surprising number of these manifest themselves as lines at the ocean surface. Lines, or slicks, are convergence zones where organic material collects. Internal waves, Langmuir circulations, topographically controlled fronts, estuarine, coastal and oceanic fronts produce linear or curvi‐linear slicks. The biological importance of these features is discussed. Slicks are ideal for investigating factors influencing meroplankton.
Behavioural variability in marine larvae
Authors: RAIMONDI PETER T. , KEOUGH MICHAEL J.
Published: July 2006

Despite increasing recognition of the importance of larval settlement, recent models have concentrated on small and large scale hydrodynamic effects as determinants of larval settlement. Implicit in most of these discussions is the assumption that variability in larval behaviour either does not exist, or is unimportant.

We present evidence that this is an inaccurate description of larval behaviour at the time of settlement. There exists considerable variation in behaviour at a number of scales, even under controlled laboratory conditions. For almost all species examined, responses to attractive and discrete stimuli were non‐uniform. The causes of variability in larval behaviour both within and between populations are largely unexplored. We suggest that variable behaviour, in response to discrete stimuli, may be a selectable trait. If so, the manifestation of such variability in individuals within a population is simply the expression of an adaptive trail. By this reasoning, differences in larval behaviour between populations are evidence for varying selective pressures. We conclude with an examination of possible consequences to a population, arising from variable larval behaviour.
The adaptive significance of life history characters in selectedorders of marine brown maeroalgae
Authors: CLAYTON MARGARET N.
Published: July 2006

Life history charaeters. which are generally eonsidered to be of eritieal signifteanee in evolution, consist of various pheiiotypie trails eoneerned with growth and reproduetion. Suites ot life history charaeters are frequently referred to as ‘strategies’. These are hypotheses which attempt to explain the adaptive significance of particular suites of charaeters. This paper reviews life history charaeters of species belonging to various orders of brown algae (Phaeophyeeae) and diseusses their possible adaptive, significance, together with the extent to which they are eonsistent with opportunistie, stress tolerant and biotieally eompetent strategies. In general, speeies belonging to the same order have broadly similar suites of life history charaeters and, thus, to some degree they share eomparable adaptive strategies. For example. the Laminariales, Fueales and Durvillaeales inelude a high proportion of biotieally eompetent speeies. many ofthe Dietyotales appear to be stress tolerant, and the Eetoearpales are typieally opportunistie. The two heteromorphie generations of speeies in the Seytosiphonales are viewed as having divergent strategies, the erustose stages showing a greater degree of stress toleranee than the opportunislie ereet stages.
Biogenic habitat structure and characteristics of temperate reef fish assemblages
Authors: HOLBROOK SALLY J. , SCHMITT RUSSELL J. , AMBROSE RICHARD F.
Published: July 2006

Assemblages of non‐cryptic, substrate‐oriented species of fish were compared on a series of reefs in Southern California, USA. Reefs were grouped according to algal cover: dense beds of giant kelp (Macrocystis pyrifera) with turf understorey; sparse beds of giant kelp with foliose algae understorey: foliose algae < 1 m in height; and open barrens. Despite affinities to particular algal substrates by many individual species, we detected no differences in fish species richness and only weak differences in species composition among reefs of different habitat types. Planktivores and species that consume macro‐invertebrates were less likely to occur on reefs that supported giant kelp; the frequencies of occurrence of three other trophic groups (piscivores, herbivores and micro‐carnivores) were unaffected by giant kelp.

Algal composition on reefs in Southern California is temporally highly dynamic. Changes in macro‐algal composition of reefs influenced population dynamics of two fish species (black surfperch and striped surfperch) examined. Overall, the weak spatial variation in fish assemblages on reefs in Southern California appears to result from relatively unspecialized ecological requirements of many species combined with temporal changes in algal structure on reefs that are rapid relative to generation times of the fish. We hypothesize that the degree of spatial differentiation in assemblages of substrate‐associated species of fish may be inversely related to the temporal constancy of biogenic reef structure.
Resource allocation patterns in Spinifex sericeus R.Br.: A dioecious perennial grass of coastal sand dunes
Authors: MAZE K. M. , WHALLEY R. D. B.
Published: July 2006

The resource allocation patterns within populations of Spinifex sericeus R.Br, were studied on the mid north coast of NSW. Sand burial and nutrient availability were two major factors influencing the allocation of resources to roots, culms, tillers and inflorescences, resulting in different growth forms in different sections of the dune. The data suggest that pollen availability may affect allocation to seeds late in the flowering season.

Spinifex sericeus was found to have a greater below‐ than above‐ground biomass, especially on the crest of the incipient foredune where sand accretion was high. The ability of culms of S. sericeus to grow upwards at a rate that generally prevents complete burial of the tillers is one mechanism which allows S. sericeus to vary resource allocation patterns in response to a varying environment.

Differences in the inflorescence characteristics of males and females indicate their different functions. The much greater floret number of males indicated the importance of pollen dispersal. Female inflorescences consisted mainly of structures other than florets and suggested the importance of the female inflorescence in seed dispersal.

Addition of nitrogen and phosphorus increased the number of spikelets and seeds but not the proportion of spikelets which produced seed.
The ecology of water‐filled treeholes in Australian rainforests: Food web reassembly as a measure of community recovery after disturbance
Authors: JENKINS B. , KITCHING R. L.
Published: July 2006

Ten water‐filled tree holes in a subtropical rainforest were emptied out thereby imposing a major perturbation on the community of organisms which occupied these habitat units. During the process of food web reassembly following this disturbance, the average number of predator species in the web increased as did the average number of prey species. Predator‐prey ratios increased in magnitude with the number of days after the disturbance. Furthermore, the characteristic mean predator‐prey ratio of the original community was gradually restored as the food web reassembled. The number of prey species was found to be a better predictor of the number of predator species during community recovery than vice versa. The increasing number of trophic links in the food web over the period of reassembly, due mainly to the increase in the number of predacious species in the web, provides a good overall measure of community recovery. The paper discusses the use of relationships among the food web statistics described within a model of food web reassembly. Such a model can be used to assess the rate of recovery of a community after a disturbance of the food web at the regional level of resolution. Further, the question of whether or not the rate of community recovery can be used to estimate ecosystem recovery with the aid of food web statistics is examined.
Soil seed densities and emergence patterns in pastures in the seasonally dry tropics of northeastern Australia
Authors: McIVOR JOHN G. , GARDENER CHRISTOPHER J.
Published: July 2006

Germinable seed densities in the surface (0–10 cm) soil of pasture communities growing at Lansdown, near Townsville, were measured during the late dry season before the first germinating rain and again during the following wet season after germination but before the input of new seed. Seedlings emerging in the field were counted at approximately weekly intervals during this period to determine emergence patterns. Twelve communities were sampled in 1980–81 and six were re‐sampled in 1981–82.

During the late dry season germinable seed densities ranged from 5000 to 40 000 seeds m‐2. Seeds of the introduced legume, Stylosanthes hamata, were present in all pastures. There were many seeds of annual grasses (Digitaria ciliaris and Brachiaria miliiformis) and sedges (Cyperus and Fimbristylis spp.) but only few seeds of perennial grasses (both native and introduced). Soil seed densities were much lower during the wet season than during the preceding dry season, particularly for the grasses.

Emergence commenced and approximately 70% of all seedlings emerged on the first major rainfall of the wet season. The subsequent emergence pattern varied between years. In 1980–81 there was a gradual and continuous increase in seedling numbers under the continuously moist conditions which prevailed. In 1981–82 further emergence occurred in discrete events related to rainfall and intervening dry periods. Maximum seedling densities exceeded 34 000 seedlings m‐2 including 29 000 grass seedlings (mainly annual species).

The implications of these results for species survival and pasture composition are discussed.
The ecology ofLagarostrobos franklinii(Hook.f.) Quinn (Podocarpaceae) in Tasmania. 2. Population structure and spatial pattern
Authors: GIBSON N. , BROWN M. J.
Published: July 2006

Analysis of stand structure and spatial patterning indicates thatLagarostrobos franklinii(Huon pine) regenerates intermittently in response to canopy disturbance. Its ability to resprout rapidly from fallen trees is likely to be important in the continued dominance of gaps by this species in competition with faster‐growing tree species. The largely riverine distribution pattern of this species is best explained by rapid vegetative spread down river systems and slow dispersal into canopy gaps away from river edges. The probability of recurrent disturbance within the lifespan of this species is high, implying that competitive exclusion of Huon pine is unlikely once it establishes at a site.
Patterns in shallow subtidal marine assemblages along the coast of New South Wales
Authors: UNDERWOOD A. J. , KINGSFORD M. J. , ANDREW N. L.
Published: July 2006

Shallow subtidal areas of rocky reefs in central and southern New South Wales may best be described as a mosaic of habitats, the distributions of which are seemingly related to depth, wave exposure and a number of biological processes, particularly herbivory. The Fringe habitat is generally found only in the most shallow waters. Forests of the laminarian alga Ecklonia radiata are often found at intermediate depths. In deeper, or more sheltered water, sponges, ascidians and red algae are more abundant and the abundances of sea urchins and other invertebrate grazers decline. Overlying this broad‐brush pattern are patches of crustose coralline algae (the Barrens habitat), the distributions of which are not clearly related to depth. Invertebrate herbivores, and sea urchins in particular, are abundant in the Barrens habitat. The Barrens habitat was most represented at the more southern locations. At the two most northern locations, reefs were shorter in length and dominated by ascidians (Pyura species).
Sampling communities of ground‐foraging ants: Pitfall catches compared with quadrat counts in an Australian tropical savanna
Authors: ANDERSEN ALAN N.
Published: July 2006

The relative abundances of ant species captured in pitfall traps was compared with those obtained by direct counts in quadrats at a savanna site in Kakadu National Park, Northern Territory. Two measures of abundance in traps were used, one based on total numbers of ants, the other on species frequency of occurrence. All species commonly recorded in quadrats were collected in traps, and their relative abundances were highly correlated on all occasions. Of the 20 most common species in quadrats, five occurred with a significantly different (in all cases lower) frequency in pitfall traps, but these species represented only 1.8–3.1% of total quadrat counts. Results from quadrats and pitfall traps were particularly similar (r > 0.8) when species‐were classified into functional groups. Frequency data from traps may sometimes overestimate the abundance of widespread, solitary foraging species (e.g. ‘Chelaner’ andTetramoriumspp.) and underestimate species with large colony sizes (e.g.Iridomyrmexspp.). Data based on total numbers of ants in traps may be more prone to distortion arising from species differences in locomotor behaviour. Species counts in traps could be scaled to reduce these distortions. The finding that pitfall traps gave results comparable with those from quadrat counts provides support for the use of pitfall traps in studies of Australian ant communities in open habitats.
Recruitment and survival in Atriplex vesicaria populations in semi‐arid western New South Wales, 1977–1987
Authors: ELDRIDGE D. J. , WESTOBY M.
Published: July 2006

The recruitment and survival of small and large shrubs of Atriplex vesicaria were examined for 21 periods from 1977 to 1987. Recruitment occurred in all seasons, including summer, and survival was independent of the size of the recruitment event. Recruitment was not related to the density of the large shrubs, suggesting that the available seed pool at this site was not limiting. Survival of both shrub components was only weakly correlated with rainfall (measured at a location between 6 and 30 km from the study transects) and with a ratio of rainfall and evaporation. Survival of small shrubs was constant over all cohorts, with half‐lives of only 7–8 months. Turnover of the population was substantial — an average of 60% of the individuals present at any one time were less than 24 months old.
Flocking and feeding in the white‐fronted chat Ephthianura albifrons: The relationship between diet, food availability and patch selection
Authors: MAJOR RICHARD E.
Published: July 2006

Censuses of white‐fronted chats were conducted three times per day, four times per month for more than 2 years in a salt‐marsh/grassland near Melbourne. Most birds Were in flocks of less than 10, although flocks of up to 50 were recorded. Diet was determined by stomach flushing 226 birds over a 12 month period and the abundance of their arthropod prey was sampled in pitfall and sticky traps located in areas where flocks aggregated and in areas where few birds were found. Diptera and Coleoptera were the major components of the diet, although the actual species varied throughout the year. On 8 of 9 occasions when differences in prey density were detected, birds aggregated in the more profitable patches. These observations suggest a relationship between food‐finding and flock formation but cannot eliminate the possibility of flocking functioning as an anti‐predator strategy.
Plant‐animal interactions and the structure and function of mangrove forest ecosystems*
Authors: ROBERTSON A. I.
Published: July 2006

Trophic interactions involving plants and animals in tropical mangrove forests have important controlling influences on several population, community and ecosystem‐level processes. Insect herbivores remove up to 35% of leaf area from some mangrove tree species and can cause the death of seedlings. Leaf chemistry and toughness and soil nutrient status all appear to be important in explaining the between‐ and among‐species variance in leaf damage. Insects also attack and damage, mainly by boring, a large proportion of mangrove seeds. Shadehouse experiments have shown that such post‐dispersal predation can have a significant effect on seedling survival, growth and biomass allocation to leaves, stems and roots. Sesarmid crabs are also responsible for severe post‐dispersal seed predation. In field trials, crabs consumed more than 70% of the seeds of five tree species. For four of these five species there was an inverse relationship between seed predation rate and the dominance of conspecific adult trees, while the within‐site distribution pattern of one tree species appears to be partially controlled by crabs. The same crab species also consume 30–80% (depending on forest type and intertidal elevation), of the annual litter fall in mangrove forests and, thus, have an important role in controlling the rate of remineralization of detritus within forests and the export of particulate matter from the forests to other nearshore habitats. The other major component of litter in the forests is wood, which is broken down relatively rapidly by teredinid molluscs (shipworms). More than 90% of the weight loss from decomposing trunks of Rhizophora species during the first four years of decay is through ingestion by teredinids. The annual turnover of dead wood mass in Rhizophora forests is equivalent to that of the processing of leaf detritus by crabs. Because of the relatively low species richness of trees and consumers in tropical mangrove forests, they are likely to serve as productive sites for further investigations of the influence of plant‐animal interactions on the dynamics of tropical forests.
Induced resistance of Gossypium australe against its most abundant folivore, Bucculatrix gossypii
Authors: KARBAN RICHARD
Published: July 2006

Induced resistance of cultivated Gossypium to its exotic, agricultural pests is well studied but little is known about whether native cottons respond to damage by endemic herbivore populations. This study examined induced responses of Gossypium australe to its most abundant folivore, Bucculatrix gossypii. Prior damage did not affect the number of new mines initiated. Survival of miners on damaged, young leaves and cotyledons was reduced compared with survival on young leaves and cotyledons of undamaged plants. However, the induced resistance was not systemic; survival of miners on older, undamaged leaves of damaged seedlings was not different from survival on older leaves of undamaged controls. This localized induced resistance did not produce an overdispersed distribution of either mines or successful mines. On the contrary, the distributions tended towards clumped, although they were not statistically distinguishable from random. Although a localized induced response affected miner survival, no effects on behaviour were observed.
Woody overstorey and herbaceous understorey biomass in Acacia harpophylla (brigalow) woodlands
Authors: SCANLAN J. C.
Published: July 2006

Extensive areas of Acacia harpophylla (brigalow) woodlands have been cleared for pasture production in Queensland. The woody regrowth of A. harpophylla influences pasture production and composition following initial development of these woodlands.

Biomass component regressions were developed using tree basal area as the predictor variable and used to estimate component yields of regrowing A. harpophylla communities. Leaf biomass of A. harpophylla reached a maximum of 12 t ha‐1 with a leaf area index of 2.5 when regrowing plants were 2.5 m high and about 10 years old. Pasture production, pasture basal area and the proportion of sown pasture species were lower at higher tree basal area of A. harpophylla. The greatest decrease was seen between 0 and 2 m2ha‐2tree basal area. Annual grasses and broadleaf herbaceous species represented a greater proportion of pasture biomass at high tree basal area.

The poor control achieved by herbicide sprays on A. harpophylla plants that are 2–2.5 m tall would be partly due to poor coverage of the herbicide spray, as leaf area index is at a maximum at this stage. A density of 1000 plants ha‐1is a threshold value above which regrowth control would be necessary at some stage to maintain acceptable pasture production and composition.

The non‐linear regression relationship between pasture production and tree basal area was similar to that observed in Eucalyptus spp. However, in the equation that relates pasture yield (Y) to tree basal area (X), Y = A + B*e(‐kX)the value of k for A. harpophylla communities was generally higher than observed in Eucalyptus spp. communities with the same potential pasture production in the absence of trees. Within even‐aged stands, the use of tree leaf biomass to predict pasture production showed no advantage over the use of tree basal area as the predictor. However, there are advantages in using tree leaf biomass as a predictor when comparing communities with different size‐ or age‐class structures.
Sign and habitat impact of banteng (Bos javanicus) and pig (Sus scrofa), Cobourg Peninsula, northern Australia
Authors: BOWMAN D. M. J. S. , PANTON W. J.
Published: July 2006

The habitat preference and impact of banteng (Bos javanicus) and pigs (Sus scrofa) in Gurig National Park, on Cobourg Peninsula, Northern Territory, was investigated by systematically sampling twelve habitats. Animal signs (banteng and pig scats) and impacts (area of rooted, trampled or pugged ground and number of rubbed tree trunks) were recorded in 696 quadrats, each 5 × 20 m. Significant differences among habitats in sign and impact were detected. Pig rooting was concentrated on wetland communities, particularly sedgelands. Banteng sign focused on monsoon forest and coastal plains, where they caused less obvious damage than pigs. There was little evidence of either ungulate in the eucalypt communities, which are the most widespread of all habitats on the peninsula.

In monsoon forests, banteng densities were approximately 70 per km‐2, Banteng, unlike pigs and buffalo, have remained near their point of introduction over the last 140 years, possibly because of the unique habitat mosaic consisting of grasslands abutting monsoon forest.
Nitrogen mineralization and nitrification in rainforests of contrasting nutrient status and physiognomic structure near Lake Eacham, northeast Queensland
Authors: MAGGS JOHN
Published: July 2006

Nitrogen mineralization and nitrification were measured using in situ incubations for 12 periods of 1 month in a structurally complex rainforest with basaltic soil, and an adjacent structurally simple rainforest with less fertile soil formed on metamorphic rock. The study was undertaken near Lake Eacham on the Atherton Tableland in northeast Queensland.

Cumulative nitrogen mineralization for 1 year did not differ between forests. It amounted to 265 ± 13 μg N g‐1 oven dry soil at the upper position (0–7.5 cm) and 122 ± 11 μg N g‐1 oven dry soil at the lower position (7.5–15 cm; mean ± s.e. for pooled data). Rates were highest during the wet season but were not strongly correlated with moisture content or temperature.

Relative nitrification (cumulative nitrate‐nitrogen production expressed as a percentage of cumulative nitrogen mineralization) at the upper position was significantly higher in the complex than the simple forest (100% c.f. 88%). At the lower position it amounted to 100% for cumulative data in both forests. Nitrate was the dominant form of inorganic nitrogen in the complex forest but in the simple forest nitrate and ammonium were of similar importance.

The association between forest physiognomic structure and nutrient status at Lake Eacham represents a more general pattern in rainforests of northeast Queensland and further study is needed to ascertain whether results from this study apply more generally.
The effect of supplementary food on home range of the southern brown bandicoot, Isoodon obesulus (Marsupialia: Peramelidae)
Authors: BROUGHTON S. K. , DICKMAN C. R.
Published: July 2006

The study investigated the relationship between home range and food abundance in a population of the southern brown bandicoot. Isoodon obesulus, in Western Australia. Home range areas were estimated seven times between 1986 and 1988 by live‐trapping, spool‐and‐line devices and fluorescent pigment tracking. The abundance of invertebrate food was measured simultaneously by placing pitfall traps within the home ranges of individual animals, and by sampling invertebrates in topsoil and litter. Home range areas tended to be negatively correlated with food abundance, especially in the autumn and winter of 1986 and 1987.

The influence of food on home range was investigated further in September 1988 by providing eight individual I. obesulus with a supplementary food mixture. Contrary to expectation, the added food caused an increase in home range area, home range overlap and displacement, as well as an influx of new individuals to food stations. In contrast, home range parameters in control (non‐fed) individuals changed little during the experiment.

The shuffling of home ranges due to feeding suggests that the home range system of I. obesulus is relatively flexible, with individuals monitoring and exploiting resources in an opportunistic manner. In contrast to previous studies, we found no evidence that I. obesulus was territorial. We speculate that individuals may be territorial at low population density if resources are defendable and intruder pressure is low, but occupy overlapping ranges if population density is high.
Ecological sensitivity of Australian rainforests to selective logging
Authors: HORNE ROSS , HICKEY JOHN
Published: July 2006

To assess the ecological consequences of selective logging in the major rainforest areas in Australia, past studies are reviewed with respect to the following: recovery of stand structure; regeneration capacity; individual tree growth and species composition of stands; hydrologie impact; floristics; wildlife; soil nutrient levels; fire susceptibility; and incursion of weeds and diseases.

Although rainforest logging has become a sensitive issue in the community and its effects are of concern to ecologists, relatively few scientific studies of selective logging have been published. Thus, the full nature and extent of ecological changes to Australian rainforests due to this form of disturbance cannot yet be determined. However, some cautious interpretation of the studies that have been completed is possible.

Following a single selective logging, the changes indicated by individual studies often appeared to be relatively minor. It is suggested that many of these effects are not extensive or irreversible and might not persist beyond structural recovery of the rainforest. However, two changes were identified as likely to persist beyond structural recovery. These are: a post‐logging difference in the proportional representation of major overstorey tree species and a reduction in the numbers of large‐diameter trees.

Further, results indicate that more extensive and longer‐lasting changes may result from multiple selective loggings, especially if the time between successive loggings is short. Even with light logging intensities, a conservative interval of at least 60 years between selective loggings, to allow canopy and below‐canopy conditions to be restored, is indicated.

Apart from disturbance frequency, the studies reviewed raise questions as to whether long‐term natural disturbance effects per se are distinguishable from long‐term selective logging effects. A need for further work is highlighted.

Overall, there appears to be a distinction between the recovery capability of the more northerly mainland rainforests and those of Tasmania. Slower growth in the more southerly rainforests, compounded by a geographical susceptibility to summer drought, increases the possibility of fire damage following selective logging.
Effectiveness of nectarivorous birds and honeybees as pollinators of Banksia spinulosa (Proteaceae)
Authors: VAUGHTON G.
Published: July 2006

Abstract
The effectiveness of nectarivorous birds and honeybees (Apis mellifera) as pollinators of Banksia spinulosa (Proteaceae) was investigated. Birds visited inflorescences in the early, mid and late flowering seasons. In contrast, honeybees visited only on days in the late flowering period when maximum temperatures exceeded 15°C. Self pollen remained on pollen presenters of flowers for up to 5 days in the early and mid periods. In the late period, when honeybees visited inflorescences, self pollen was removed within 2 days. Pollen removal was similar for caged (birds excluded) and open inflorescences in the late period, indicating that most pollen was removed by honeybees. In the early and mid periods, honeyeaters pollinated 22% and 27% of flowers on open inflorescences, respectively. In the late period, when both birds and bees visited inflorescences, 64–73% of flowers on open inflorescences were pollinated. Foraging by honeybees resulted in pollen deposition as 38% of flowers on caged inflorescences were pollinated. Throughout the flowering season a similar number of pollen grains was deposited per stigma. There were 3.0–3.7 pollen grains per stigma on open inflorescences in the late period, although only 2.0 grains per stigma on caged inflorescences. In the early and mid periods, fewer caged than open inflorescences produced fruits, indicating the importance of honeyeaters to reproductive success at these times. In contrast, in the late period when honeybees visited inflorescences, fruit‐set was similar on caged and open inflorescences. Overall, these results indicate that honeybees were effective pollinators of B. spinulosa.
Environmental influences on the distribution of the rareEucalyptus paliformisand the commonE. fraxinoides
Authors: PROBER S. M.
Published: July 2006

AbstractEucalyptus paliformisis restricted to seven small populations within an area of <5 km2 on the Wadbilliga Plateau of south‐eastern NSW. It occurs as a dominant tree in habitats superficially similar to those of the more widespreadE. fraxinoides, which dominates forests immediately adjacent to theE. paliformispopulations. This study examined factors which may influence the replacement ofE. fraxinoidesbyE. paliformis, and similarly, factors which excludeE. paliformisfrom sites dominated byE. fraxinoides.

Seedling growth and competition experiments indicated thatE. fraxinoidesoutcompetesE. paliformisunder unburnt field conditions, on field soils, under high and low moisture regimes, under high light and high nutrient conditions, and under a range of temperature regimes. Thus, it is likely thatE. paliformisis excluded fromE. fraxinoidessites by competition. However, further investigation of the competitive relationship between the two species under recently‐burnt conditions is still required to test this hypothesis.

The exclusion ofE. fraxinoidesfromE. paliformissites is unlikely to be due to soil types or moisture regimes. Further, temperature regimes do not appear to be important in reducing the competitive advantage ofE. fraxinoidesoverE. paliformis, leaving survival at low temperature extremes as the most promising avenue for further investigation. Temperature measurements, and evidence for low temperature dormancy mechanisms in seeds ofE. paliformisbut notE. fraxinoides, support the hypothesis thatE. fraxinoidesis excluded fromE. paliformissites by low temperature extremes.
Estimating plant biomass: A review of techniques
Authors: CATCHPOLE W. R. , WHEELER C. J.
Published: July 2006

Abstract
Many different techniques have been used to estimate biomass for ecological, agricultural and forestry research. The most suitable technique depends on available budget, accuracy required, structure and composition of the vegetation, and whether species and component biomass are required. A survey of the methods that have been used to estimate biomass is given, and the advantages and disadvantages of direct sampling, calibrated visual estimation and double sampling techniques are discussed. The relative cost and accuracy of each technique are summarized and recommendations are made for the use of the techniques in different vegetation complexes, such as discrete shrubs or trees, patchy vegetation, homogeneous vegetation, and species‐rich inhomogeneous heathland.
Homogeneity analysis: Assessing the utility of classifications and maps of natural resources
Authors: BEDWARD M. , Keith D. A. , PRESSEY R. L.
Published: July 2006

Abstract
A quantitative measure of homogeneity, based on the average within‐group association between samples, is proposed as a multivariate measure of the information content of classifications and maps. Homogeneity analyses are used to investigate questions of scale and the choice of attributes in the context of vegetation mapping. Previous studies in classification and mapping of soil types suggested that an optimum map scale or number of classification groups can be defined using homogeneity. This does not seem to be the case with vegetation data although homogeneity analysis can be used to define the coarsest acceptable scale and to quantity the benefits of mapping at finer scales. Homogeneity analysis is used here to compare the information content of classifications derived from various attributes with one based on the whole flora. For the data set examined, a classification derived from canopy species composition is as informative as one based on full rloristic composition for the scales at which we would normally map, whereas an environmental classification is less so. Further applications of homogeneity analysis are suggested.
Distribution and abundance of fungal sporocarps and diggings of the Tasmanian bettong, Bettongia gaimardi
Authors: TAYLOR R. J.
Published: July 2006

Abstract
The distribution and abundance of diggings of the Tasmanian bettong Bettongia gaimardi and sporocarps of hypogean fungi (the major dietary item of bettongs) were studied in an area of dry sclerophyll forest in northern Tasmania. Digging activity was greatest during August. Sporocarp production was expected to be greatest at this time due to high soil moisture levels. The distribution of both hypogean sporocarps and the diggings of bettongs was highly clumped. Degree of clumping of diggings varied seasonally being greatest in summer and lowest in winter. Digging activity was greatest in sandy soils and least in dolerite soils. This was thought to result from the lower fertility sandy soils having greater densities of sporocarps. Lateritic soils, although the most infertile, had fewer diggings than sandy soils. This is probably due to the difficulty of digging in these gravelly, often cemented soils. The depth of diggings was greatest in winter when soil moisture was high. Mesophellia was the most frequently occurring sporocarp and spores of this genus were the most abundant in the faecal pellets of bettongs.
Effect of mistletoes (Amyema preissii) on host (Acacia victoriae) survival
Authors: REID N. , Smith D. M. Stafford , VENABLES W. N.
Published: July 2006

Abstract
The effect of mistletoes Amyema preissii on the survival of fast growing trees of Acacia victoriae was investigated in arid central Australia. Trees with different levels of experimentally induced mistletoe infection were monitored for 4 years. Analysis of covariance failed to reveal a treatment effect of infection on host survival. Loss of trees early in the experiment reduced the statistical power of the analysis, and variable infection success and the establishment of bird‐dispersed mistletoes on experimental trees blurred the distinction between treatments. However regression analysis showed a significant relationship between the volume of mistletoe and tree mortality. The implications for the design of future experiments are discussed.