bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sampling communities of ground‐foraging ants: Pitfall catches compared with quadrat counts in an Australian tropical savanna
Authors: ANDERSEN ALAN N. 
Published: July 2006

AbstractThe 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

AbstractThe 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

AbstractCensuses 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

AbstractTrophic 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

AbstractInduced 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

AbstractExtensive 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

AbstractThe 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

AbstractNitrogen 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

AbstractThe 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

AbstractTo 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.
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.
Application of repeated measures designs in environmental impact and monitoring studies
Authors: GREEN R. H. 
Published: July 2006

Abstract
Traditional environmental studies have employed sampling at different times, but based on re‐randomized ‘replicate’ samples taken at each time. For example, in a 4 year monitoring study of near‐shore marine benthic communities there might be three box cores collected annually at each of three depths along each of three transects. Repeated measures designs, long used in medicine and the social sciences, are based on resampling replicates (e.g. sites) at a series of times. In such designs spatial sampling variability is not used for tests of environmental impact. Error for such tests is based on variability of time trends among similar sites (similar with respect to impact). For example in a tropical oil spill study five oiled and five unoiled coral reefs were studied over 5 years. Error for tests of oil impact was based on variability among reefs (within degree‐of‐oiling category) in the year‐to‐year trends of biological response variables. It was not based on variability among field samples within reefs at given times.The two approaches (univariate and multivariate) to repeated measures analysis of variance are described. The pros and cons of each are discussed, as are the assumptions and consequences of their violations. Emphasis is especially placed on the adequacy of error degrees of freedom in the two approaches, and some exploration of power to detect impact is presented. Examples of application of repeated measures designs to various impact and monitoring studies are presented and discussed, including (i) interpretation of significant effects; (ii) decomposition of effects by contrasts (e.g. before vs after impact); and (iii) modelling time trends by polynomial and cosine functions.
The ecological impact of Phytophthora cinnamomi in the Stirling Range National Park, Western Australia
Authors: WILLS R. T. 
Published: July 2006

Abstract
An assessment of the impact of the soil‐borne pathogenic fungus, Phytophthora cinnamomi (Oomycetes, Peronosporales), on the plant communities of the Stirling Range National Park was carried out between December 1988 and April 1989. A total of 541 plant species were collected, with the Proteaceae and the Myrtaceae the two largest families in the study region. Of the 330 species assessed for susceptibility to P. cinnamomi, 118 (36%) were recorded as having at least some individuals in a population judged to have been killed by the fungus and 33 (10%) were highly sensitive to the pathogen (more than 80% of plants in a population killed). Several families had large numbers of susceptible species, while others were apparently unaffected by the pathogen. Notably, 85% of proteaceous species assessed were rated as susceptible to P. cinnamomi. Proteaceous elements had a mean projective foliage cover of 40% in healthy plant communities, but had a mean cover of only 10% at sites that had a long history of infestation with the fungus. In contrast, some species with low levels of susceptibility to the pathogen, such as some monocotyledons, were found to be more abundant at old‐infested sites than at healthy sites. Growth form may also influence susceptibility, with herbaceous perennials, annuals and geophytes assessed in this survey apparently unaffected by the fungus whereas 48% of woody perennials surveyed were susceptible.Changes in the floristic structure of plant communities may influence the composition of associated animal communities. In particular, vertebrate flower visitors may be vulnerable since 59% of the species with vertebrate‐pollinated flowers were found to be susceptible to the pathogen. This research highlights the serious ecological impact of P. cinnamomi on native plant communities and suggests that significant components of the flora and associated fauna of the southwest of Western Australia are endangered by this virulent pathogen.
The intertidal distribution of the grey mangrove (Avicennia marina) in southeastern Australia: The effects of physical conditions, interspecific competition, and predation on propagule establishment and survival
Authors: CLARKE P. J. , MYERSCOUGH P. J. 
Published: July 2006

Abstract
The upper and lower limits of the distribution of mature Avicennia marina lie between mean high water and mean sea level in open estuaries in southeastern Australia. Newly established seedlings are highly variable in abundance, but are rarely found in the saltmarsh or on mudflats. Their distribution is unlikely to be limited by dispersal because propagules disperse into the saltmarsh and to intertidal mudflats, but their establishment may be limited by physicochemical conditions, interspecific competition and predation.The model that physicochemical conditions control the intertidal limits of establishment of seedlings was accepted for propagules stranding in the saltmarsh but rejected for those stranding on mudflats. No seedlings established on saltmarsh sediments but similar numbers of seedlings established within light gaps in adult mangrove stands and on intertidal mudflats. The model that interspecific interaction with freeliving macroalgae (Hormosira banksii) reduces the establishment of seedlings on mudflats covered with macroalgae or in stands with a ground cover of macroalgae was accepted. Under controlled conditions five times as many propagules established on cleared ground compared with ground covered with macroalgae. Predators also reduce seedling establishment, but the model that they preferentially act on propagules stranding on the mudflat was rejected. The low number of seedlings found on mudflats without macroalgae appears to relate to wave and current effects on establishment and the effects of waterlogging or fouling on survival.