bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of body size and water temperature on grazing rates of four intertidal gastropods
Authors: PETRAITIS P. S.
Published: July 2006

Abstract
Rates of radular activity were measured in four species of Australian gastropods. The species were Austrocochlea constricta, Bembicium nanum, Cellana tramoserica, and Nerita atramentosa. Work was done in Botany Bay at Cape Banks, NSW, Australia from September 1989 to June 1990. A hydrophone was used to record radular raspings of snails in situ. Averages based on all observations showed Cellana had the fastest rate with 80 rasps/min, and was followed by Austrocochlea (71 rasps/min), Bembicium (57), and Nerita (39). Faster rates were associated with warmer water temperature and smaller body sizes in all species except Bembicium. The potential for these differences in radular activity affecting competitive interactions is discussed.
Impact of powerful owl predation on a population of the greater glider: A response to Kavanagh (1988)
Authors: PAVEY C. R.
Published: July 2006

Abstract
Kavanagh (1988) concluded that 46 months of predation by a pair of powerful owls caused a decline of over 90% in a greater glider population over an area of 100 ha in southeastern New South Wales. He suggested the owls concentrated their foraging activities by taking gliders in one pocket of their home range before moving to the next pocket once the glider population fell to levels at which they were difficult to catch. The assumptions on which Kavanagh's work is based and the methodology of the study are assessed here, and it is argued that the data presented are not sufficient to support the interpretations of powerful owl ecology made in the paper. In particular, alternative explanations of the glider population decline were not considered and home range use by the owls was not examined in enough detail to discern any spatial movement patterns.
Environmental impact studies on marine communities: Pragmatical considerations
Authors: WARWICK R. M.
Published: July 2006

Abstract
The measurement of changes in the structure of natural marine communities is widely used for the detection and monitoring of man's impact on the sea. Such studies are almost always a compromise between the scientific ideal and political, financial and logistical constraints. This paper considers a number of these constraints, suggests some possible solutions, and discusses the consequences (in terms of loss of information) of adopting strategies which might be considered suboptimal.

Identification of all organisms in a community to species level is a major time and cost constraint. Many recent studies have shown that very little information is lost by working at a taxonomic level higher than species (e.g. family or even phylum). This implies a functional coherence of species within each higher taxon. Indeed, there are theoretical reasons, and some empirical evidence, for supposing that community responses to human perturbations may be more easily detected above the noise of natural variability by working at high taxonomic levels.

Many environmental impacts, for example oil spillages from tankers, are accidental and it is unusual to have the luxury of a time‐series of data from the site prior to the incident. Good spatial control samples may also be difficult to obtain in a heterogeneous environment. Absolute rather than comparative measures of community degradation are valuable in this context. Methods which fall into this category include comparisons of community structure with some theoretical expectation or with empirical‘training’ data, comparing attributes of community structure that respond differently to perturbation, or identifying highly conservative properties of unperturbed communities that are modified in a predictable way by perturbation.

All studies are selective with regard to which components and attributes of the biota should be investigated. The choice frequently depends on local expertise and research interests, rather than on an objective decision about what biological data are most appropriate for the problem in hand. The paper concludes by a discussion of the relative merits of the various alternatives.
Non‐parametric multivariate analyses of changes in community structure
Authors: CLARKE K. R.
Published: July 2006

AbstractIn the early 1980s, a strategy for graphical representation of multivariate (multi‐species) abundance data was introduced into marine ecology by, among others, Field,et al.(1982). A decade on, it is instructive to: (i) identify which elements of this often‐quoted strategy have proved most useful in practical assessment of community change resulting from pollution impact; and (ii) ask to what extent evolution of techniques in the intervening years has added self‐consistency and comprehensiveness to the approach. The pivotal concept has proved to be that of a biologically‐relevant definition of similarity of two samples, and its utilization mainly in simple rank form, for example ‘sample A is more similar to sample B than it is to sample C’. Statistical assumptions about the data are thus minimized and the resulting non‐parametric techniques will be of very general applicability. From such a starting point, a unified framework needs to encompass: (i) the display of community patterns through clustering and ordination of samples; (ii) identification of species principally responsible for determining sample groupings; (iii) statistical tests for differences in space and time (multivariate analogues of analysis of variance, based on rank similarities); and (iv) the linking of community differences to patterns in the physical and chemical environment (the latter also dictated by rank similarities between samples). Techniques are described that bring such a framework into place, and areas in which problems remain are identified. Accumulated practical experience with these methods is discussed, in particular applications to marine benthos, and it is concluded that they have much to offer practitioners of environmental impact studies on communities.
Interspecific competition: A mechanism for rodent succession after fire in wet heathland
Authors: HIGGS PETER , FOX BARRY J.
Published: July 2006

Abstract
A competitive interaction between two species of sympatric native rodents was demonstrated experimentally in Myall Lakes National Park (NSW, Australia). The previously documented replacement of Pseudomys gracilicaudatus by Rattus lutreolus in areas of wet heath in this region implied that competition may be the mechanism facilitating this succession. We present experimental evidence to support this suggestion. Removal of the larger R. lutreolus caused a significant increase in abundance of P. gracilicaudatus on five experimental sites in comparison to five unmanipulated control sites. The sites used in this experiment were chosen from three ages of wet heath regenerating after fire. These three ages represent key stages in the replacement of P. gracilicaudatus by R. lutreolus and the occurrence of competition in each of these ages indicates that competition plays an important role in this succession. In the initial stages of the experiment when R. lutreolus were removed they were replaced by new R. lutreolus individuals. This has been interpreted as evidence of strong intraspecific competition. After removal of R. lutreolus, P. gracilicaudatus expanded its habitat range into microhabitats that had formerly been occupied by R. lutreolus and reduced its range in microhabitats previously occupied by P. gracilicaudatus. This leads us to believe that P. gracilicaudatus was occupying inferior microhabitat before the removal of R. lutreolus, which had excluded it from more preferable microhabitat.
Relationship between nectar production and yearly and spatial variation in density and nesting of resident honeyeaters in heathland near Sydney
Authors: PYKE G. H. , O'CONNOR P. J. , RECHER H. F.
Published: July 2006

Abstract
The maximum density of resident honeyeaters in heathland near Sydney was very similar from one area and year to another, despite large variation in production of nectar‐energy. The most likely explanation for this is that density is determined by the spacing behaviour of birds rather than by nectar production or other factors. Within years, nesting by these residents was positively correlated with temporal variation in production of nectar‐energy and 90% of nesting occurred when the estimated average amount of energy available in the heathland per pair exceeded that required to support parents and young. Most nesting and the highest nectar production consistently occurred between April and July.
Filtering rates of Daphnia carinata King (Crustacea: Cladocera) on the blue‐green algae Microcystis aeruginosa Kütz. and Anabaena cylindrica (Lemm.)
Authors: KOBAYASHI T.
Published: July 2006

Abstract
Non‐toxic strains (by mouse toxin assay test) of unicellular Microcystis aeruginosa and short filamentous Anabaena cylindrica were fed to Daphnia carinata in the laboratory at an algal volume concentration of 4.0 mm3 L−1 at 24 ± 1°C. The filtering rates (FR, mL animal−1 hr−1) of D. carinata on M. aeruginosa and A. cylindrica increased with increasing body length (L, mm), and were expressed as a power curve: FR = 0.061L209. and FR = 0.232L2.09, respectively. The potential for control of natural blue‐green algal populations by D. carinata grazing is discussed briefly.
Establishment of two dry monsoon forest tree species on a fire‐protected monsoon forest‐savanna boundary, Cobourg Peninsula, northern Australia
Authors: BOWMAN D. M. J. S.
Published: July 2006

Abstract
A numerical classification of presence‐absence data of vascular plant species on a transect across a dry monsoon foresl‐Eucalyptus savanna boundary at Cobourg Peninsula was used to define savanna, ecotone or monsoon forest communities. The boundary was protected from fire. After 4 years no Aglaia rufa seedlings had established in 24 permanent quadrats (1 × 4 m) in the savanna while three Diospyros maritima seedlings established in these savanna quadrats. The number of established A. rufa seedlings in 26 ecotone quadrats fell by 50% to one individual, the number of D. maritima seedlings increased by 43% to a total of seven individuals. After 3 months significantly more transplanted D. maritima seedlings had died in the savanna than the monsoon forest, but survival of A. rufa was high, and not significantly different, in both communities. Seedlings from both species did not have significantly greater survival in the monsoon forest compared to the savanna, 42 months after transplantation.
An assessment of pollinator visitation toBanksia spinulosa
Authors: CARTHEW S. M.
Published: July 2006

AbstractRemote photo‐monitoring ofBanksia spinulosainflorescences indicated that birds, mammals and insects were regular visitors. These included the sugar glider, brown antechinus, eastern pygmy possum, eastern spinebill, honeybee and several moth species. Eastern spine‐bills were recorded at all inflorescences monitored while visitation by other animals was more sporadic. Inflorescences were visited at least once every 24 h, and visitation frequency was approximately evenly distributed during the day and night. Examination of pollen tube growth from experimental treatments indicated that pollination success was similar from both nocturnal and diurnal visitors. However, nocturnal visitors were more effective at removing pollen from newly opened flowers. The behaviour of mammals at inflorescences was such that they would transfer much more pollen to flowers than other visitors, and probably contact receptive stigmas more often. Overall, mammals were considered to be slightly more effective pollinators than the more obvious daytime visitors, eastern spinebills. Although insects visited regularly, they were thought to be less effective at pollinating flowers than vertebrate visitors. Moths carried very little pollen, and the foraging behaviour of other insects was unlikely to promote much pollination.
Water relations of the canopy species in a Banksia woodland, Swan Coastal Plain, Western Australia
Authors: DODD J. , BELL D. T.
Published: July 2006

Abstract
Diurnal and seasonal water relations were measured in selected species of a Banksia woodland at a site with groundwater at a depth of 6–7 m. The canopy co‐dominants Banksia attenuata and Banksia menziesii exhibited similar patterns of variation in water relations, both diurnally and seasonally. Stomatal conductance was usually 0.4–0.5 cm s−1 diurnally and seasonally and, generally, did not respond to water deficit and other factors. Transpiration was correlated positively with factors indicative of atmospheric evaporative demand, especially total global radiation and pan evaporation, and was highest in summer when canopy water use reached 2.1 mm d−1. Xylem pressure potential at dawn averaged −0.25 MPa in both species throughout the year. Minimum xylem pressure potential varied seasonally and was negatively correlated with transpiration. Seasonal means of minimum xylem pressure potential varied from −1.0 MPa in winter to −1.5 MPa in early summer. Both Banksia species appeared to function as phreatophytes, utilizing groundwater which enabled them to maintain high rates of water use in late summer. Water use over a 12 month period totalled 635 mm, of which the canopy and understorey contributed 61% and 39%, respectively. Water use in the woodland was dominated by the canopy in late summer and the understorey at other times.
Water relations of understorey shrubs in a Banksia woodland, Swan Coastal Plain, Western Australia
Authors: DODD J. , BELL D. T.
Published: July 2006

Abstract
Diurnal and seasonal water relations were measured in understorey species from a Banksia woodland. The shrubs exhibited various responses to summer drought. Stirlingia latifolia had high xylem pressure potential and transpiration in late summer. Adenanthos cygnorum maintained high xylem pressure potential year round with dawn values around − 0.3 MPa and minimum values around −1.3 MPa, but showed severe restriction of transpiration in late summer. Eremaea pauciflora and Jacksonia floribunda had high transpiration and xylem pressure potential levels in early summer, but exhibited water stress in late summer when transpiration rates were low and minimum xylem pressure potentials were as low as − 5.5 MPa. Late summer xylem pressure potentials in 27 other shrub species were, in general, inversely related to root system depth with minimum values below − 5.0 MPa in some species. The water relations of S. latifolia, E. pauciflora and J. floribunda indicated a phreatophytic habit: all possessed deep roots of sufficient size to reach groundwater that was located 6–7 m deep at the study site. Stirlingia latifolia functioned phreatophytically year round, while E. pauciflora and J. floribunda were phreatophytes until the falling water table carried ground‐water beyond the reach of their roots in late summer. However, most understorey species depended on soil‐stored water. Water use by the understorey was greatest in early summer.
Floristics and soil relations of upland swamp vegetation near Sydney
Authors: KEITH D. A. , MYERSCOUGH P. J.
Published: July 2006

AbstractWe examined relations between vegetation and soils, using multivariate methods, in hitherto poorly‐known upland swamps on the Woronora Plateau, south of Sydney. A major trend in floristic composition was related to the height and cover of the herbaceous stratum and reflected a gradient in soil moisture and nutrients. A second trend in floristic composition was related to the height and cover of the shrub stratum, and may reflect the influence of recurring fires on certain dominant shrub species. Five plant communities were recognized on the basis of floristic composition and were distinguishable by their different soil habitats and/or structural characteristics. We report some of the highest species‐richness values in the world (at scales of 1–15 m2) for shrub/sedge‐dominated vegetation, with up to 70 vascular plant species in 15 m2. Variation in species richness is inversely related to the resource gradient and positively related to the penetration of light through the vegetation canopy. This pattern is consistent with resource‐competition models and warrants further investigation.
Preliminary environmental reconstructions from late Quaternary pollen and mollusc assemblages at Egg Lagoon, King Island, Bass Strait
Authors: D'COSTA D. M. , GRINDROD J. , OGDEN R.
Published: July 2006

Abstract
A late Quaternary environmental record is currently being developed from Egg Lagoon, King Island, Bass Strait, a site which is geographically well situated to contribute towards a history of the Bass Strait region. Environmental reconstructions are based on a stratigraphic survey and pollen, charcoal and mollusc analyses of sediment core samples. The recorded stratigraphy includes five sedimentary units representing estuarine‐marine, freshwater lake and swamp depositional environments. Amino‐acid racemization analyses of marine shells indicate a greater than last interglacial age for the basal estuarine‐marine unit, while radiocarbon analyses of organic muds and wood suggest that a substantial section of the overlying freshwater lake and swamp facies is beyond the conventional limit for this technique. Local pollen assemblages represent freshwater lake and swamp plant communities that have varied presumably according to water level changes at the site. Regional pollen assemblages represent terrestrial herbaceous communities, believed to have existed under cooler and drier climates than today, and Eucalyptus‐ and Phyllocladus‐dom'maied forests and woodlands from periods with greater effective precipitation than at present. A sustained increase in charcoal representation dating from at least 39 000 years before the present may indicate an anthro‐pogenically induced change in the fire regime, consistent with the earliest dates for human occupation in mainland Tasmania.
Recolonization by Collembola of rehabilitated bauxite mines in Western Australia
Authors: GREENSLADE PENELOPE , MAJER J. D.
Published: July 2006

Abstract
The collembolan faunas of 30 bauxite mines rehabilitated by a range of different methods between 1966 and 1977, and three forest plots were surveyed in the spring and summer of 1978–79 with the aim of studying the restoration of decomposer activity in degraded areas. The rehabilitation methods included seeding and planting with a variety of native or exotic plant species. Physical and botanical parameters of the plots were also measured. Sixty species of Collembola were collected from the rehabilitated areas; nine of the 28 species found in the forest plots were not present on the mined sites. Principal components analysis suggested that the species richness of the collembolan community in rehabilitated areas is positively correlated with plot age. A parametric correlation analysis using a number of collembolan community characteristics revealed that, among other factors, the development of a species rich collembolan fauna is positively correlated with plant species richness and diversity, and also with percentage plant cover. These results provide directions for improving rehabilitation practices.
Influence of successional stage of Eucalyptus regnans (mountain ash) on habitat use by reptiles in the Central Highlands, Victoria
Authors: BROWN G. W. , NELSON J. L.
Published: July 2006

Abstract
Eleven sites, representing different successional stages of Eucalyptus regnans‐dominated forest in the Central Highlands of Victoria, were selected to identify potentially important habitat variables for heliothermic reptiles, three species (Eulamprus tympanum, Niveoscincus coventryi, Pseudemoia spenceri) of which were common at these sites. Analyses reveal that many forest attributes are strongly correlated with stand age and that some are significant habitat variables for some of these species. ‘One‐at‐a‐time’ modelling of habitat variables reveals that counts of E. tympanum are most strongly correlated with the proportion of grass as substrate (−ve), moss cover of logs (−ve) and litter depth (+ ve); N. coventryi counts are most significantly related to litter depth (−ve), numbers of logs (−ve), log diameter (−ve), the proportion of bare ground as substrate (−ve) and length of sunny patches (+ ve); P. spenceri counts are most significantly related to the number of sunny patches (−ve) and moss cover of logs (−ve). The total reptile count is most significantly correlated with stag diameter (−ve) and log diameter (−ve). Predictive equations for each of the common species are also presented, using measured habitat variables, and these, along with ‘one‐at‐a‐time’ models, indicate that a number of factors determine reptile occurrence or abundance and that no single predictor variable is apparent.
Differential habitat affinities of five species of fruitpiercing moths (Lepidoptera: Noctuidae) in their utilization of Tinospora smilacina Benth. as a larval host plant in north Queensland
Authors: FAY H. A. C. , HALFPAPP K. H.
Published: July 2006

Abstract
Three habitats, each containing a different form (rainforest, coastal and dry tropics) of the twining vine Tinospora smilacina, and a fourth with two of these forms were routinely sampled between 1986 and 1989 for larvae of fruitpiercing moths, to ascertain spatial and temporal utilization of this plant. Othreis fullonia and Othreis materna occurred on all forms in all habitats, predominantly between November and March for the former and January to June for the latter. Although Rhytia cocalus utilized two forms of T. smilacina it preferred the rainforest habitat to which Othreis jordani and Khadira aurantia were essentially confined. While the degree of cohabitation between any two moth species was greatest in the drier inland habitat, where only O. materna and O. fullonia occurred during a limited season, there was considerable temporal separation of any two species utilizing T. smilacina in any habitat. Field and laboratory evaluation of alternative menisperm hosts suggested O. fullonia, O. jordani and K. aurantia were generalists while O. materna and R. cocalus confined their feeding to the genus Tinospora. The differential habitat affinities and host plant acceptance of these moths are pertinent to their variable seasonal activity, local importance and general pest status.
The climbing behaviour of Cerithidea anticipata (Mollusca: Gastropoda): The roles of physical and biological factors
Authors: McGUINNESS K. A.
Published: July 2006

Abstract
Many molluscs in tidal wetlands climb trees as the tide rises, a behaviour usually assumed to be a means of avoiding subtidal predators. Some species are more active during neap tides, when the access of subtidal predators to the forest is limited, but rest on trees during spring tides. Cerithidea anticipata, which inhabits the mangrove forests around Darwin Harbour (Northern Territory, Australia), displayed almost exactly the opposite pattern. This species climbed higher, and was less active, during neap tides that did not flood the forest than during spring tides. In experiments with tethered snails, individuals prevented from climbing died during neap tides, apparently from physiological stress. Further, individuals resting on trees around clearings, usually selected shaded sites. These results suggest that the major reason C. anticipata climbed was to avoid physiological stress during neap tides, not subtidal predators during spring tides. There was some evidence of predation under the canopy, but the rate was relatively low and the species responsible appeared to be resident in the forest.
Atypichthys strigatus (Pisces: Scorpididae): An opportunistic planktivore that responds to benthic disturbances and cleans other fishes
Authors: GLASBY T. M. , KINGSFORD M. J.
Published: July 2006

Abstract
Atypichthys strigatus (Günther) were abundant on temperate reefs in New South Wales, Australia. Dietary analyses indicated that they feed primarily on plankton, but also consume benthic organisms. Initial observations suggested thai A. strigatus respond to disturbances of the substratum for the purpose of feeding. The substratum in barrens and kelp habitats was experimentally disturbed to examine the response by A. strigatus. Significantly more A. strigatus were found in disturbed areas than in undisturbed areas and their feeding rate was greater in disturbed areas. The response by A. strigatus to disturbance was the same in barrens and kelp habitats, although there was a more marked response in the barrens habitat. Atypichthys strigatus also responded to natural disturbance by large reef fishes (e.g. Achoerodus viridis: Labridae). Furthermore, A. strigatus of a broad range of sizes (25–90 mm standard length) were observed cleaning other reef fishes. The behavioural flexibility of A. strigatus probably leads to increased feeding opportunities, and hence increased foraging success, for the fish. Moreover, it raises questions about the accuracy of partitioning fish species according to one trophic group.
Long‐term transpiration in two eucalypt species in a native woodland estimated by the heat‐pulse technique
Authors: FARRINGTON P. , BARTLE G. A. , WATSON G. D. , SALAMA R. B.
Published: July 2006

Abstract
The heat‐pulse method was used to estimate transpiration rates continuously for periods up to 2 years in mature trees of Eucalyptus wandoo and Eucalyptus salmonophloia at two topographic locations in a remnant native woodland in the Western Australian wheatbelt. Annual transpiration per tree ranged from about 11400 to 18000 L per tree. Highest transpiration rates occurred in late spring or early summer, depending on rainfall distribution. The trees were able to rapidly utilize water following heavy rain outside the agricultural growing season. Extrapolating transpiration rates from single trees to an area of woodland showed that annual transpiration at the ridge site was 150 mm and 168 mm at a site alongside a drainage line. Scaling up transpiration from individual trees requires caution and should allow for variability in trees and soils. The role of trees in curtailing salinization is discussed.
Population‐biomass dynamics and the absence of ‐ 3/2 self‐thinning in the clonal weed Salvinia molesta
Authors: ROOM P. M. , JULIEN M. H.
Published: July 2006

Abstract
In the field, the population density (n) of crowded, living ramets of Salvinia molesta ranged from 2500 m −2 in nutrient‐poor water to more than 30 000 m−2 in nutrient‐rich water. Biomass of living shoots (B) in some localities exceeded 600 gm−2 dry weight (150 tonnes ha−1 fresh weight) and shoots plus roots of living and floating dead material exceeded 1600 gm−2 dry weight (400 tonnes ha−1 fresh weight). The ultimate limit B= 105n0.5 suggested by previous authors was not exceeded. The highest n and smallest ramets occurred in nutrient‐rich water and B was a linear function of n. Field experiments confirmed no effect of n, but a strong effect of nutrient availability, on ramet weight.

In a glasshouse experiment, ramet populations did not ‘self‐thin’ along the log log B‐n trajectory of slope ‐0.5, which has been suggested for aclonal plants, but followed trajectories having slopes closer to +1.0 before halting at the ambient B‐n limit. Nutrient concentrations in the plants increased during the experiment, causing ramet size to decrease and slopes of log log B‐n trajectories to depart from +1.0 by amounts which reflected the degree to which nutrient concentration had changed. Under constant conditions, mean ramet size is expected to remain constant and log log B‐n trajectories to travel in a straight line of slope +1.0 to the ambient B‐n limit. This behaviour of salvinia, whose ramets consist of a single structural module, is contrasted with that expected of clonal plants whose ramets are made up of multiple structural modules.

A logistic model explained the increases in n and biomass of living and dead ramets when ramets were assumed to have constant longevity, constant time to decay, and when both the B‐n limit and size of ramets were dependent on nitrogen content of the plant. There was no indication that physiological integration within phenets halted production of new ramets when carrying capacity was reached and new ramets continued to be produced on top of older ramets. Rates of ramet mortality were equal to, and dependent on, rates of ramet natality.
Biological guidelines for freshwater sediment based on BEnthic Assessment of SedimenT (the BEAST) using a multivariate approach for predicting biological state
Authors: REYNOLDSON TREFOR B. , BAILEY R. C. , DAY K. E. , NORRIS R. H.
Published: July 2006

Abstract
This paper describes the first results for an alternative approach to the development of sediment quality criteria in the nearshore areas of the Laurentian Great Lakes. The approach is derived from methods developed in the United Kingdom for establishing predictive relationships between macroinvertebrate fauna and the physico‐chemistry of riverine environments. The technique involves a multivariate statistical approach using (i) data on the structure of benthic invertebrate communities, (ii) functional responses (survival, growth and reproduction) in four sediment toxicity tests (bioassays) with benthic invertebrates; and (iii) selected environmental variables at 96 reference (‘clean’) sites in the nearshore areas of all five Great Lakes (Lakes Superior, Huron, Erie, Ontario and Michigan). Two pattern recognition techniques (using the computer software package PATN) are employed in the analysis: cluster analysis and ordination. The ordination vector scores from the original axes of the pattern analysis are correlated (using CORR in SAS) with environmental variables which are anticipated to be least affected by anthropogenic activities (e. g. alkalinity, depth, silt, sodium etc.). Multiple discriminant analysis (MDA) is used to relate the site groupings from the pattern analysis to the environmental variables and to generate a model that can be used to predict community assemblages and functional responses at new sites with unknown but potential contamination. The predicted community assemblages and functional responses are then compared with the actual benthic communities and responses at a site, and the need for remedial action is determined.

The predictive capability of the discriminant model was confirmed by performing several validation runs on subsets of the data. An example of the use of the model for sediment in Collingwood Bay (an area of concern designated by the IJC in Georgian Bay, Lake Huron) is presented and the technique is shown to be more precise in determining the need for remediation than the currently used provincial sediment quality criteria based on Screening Level Concentration (SLC) and laboratory toxicity tests. The ultimate goal of the study is the development of a method to determine the need for, and the success of, remedial action and to predict what benthic communities should look like at a site if it were clean and what responses of organisms in sediment toxicity tests constitute an acceptable end‐point.
The effects of pitfall trap diameter on ant species richness (Hymenoptera: Formicidae) and species composition of the catch in a semi‐arid eucalypt woodland
Authors: ABENSPERG‐TRAUN MAX , STEVEN DION
Published: July 2006

AbstractAnts play an important role in Australian biodiversity and environmental impact assessments, with pitfall‐trapping being the principal sampling method. However, the relationship between trap diameter and ant species catch has not been investigated in the context of survey design. Using four different trap diameters, each at a density of one trap per 100 m2, the present study asks three questions: (i) given an equal number of traps, do traps with larger diameters catch more species than smaller‐diameter traps?; (ii) do traps with small diameters bias against large or rare species?; (iii) for equal area of the trap mouth, do small but more numerous traps catch more species than fewer but large traps? A total of 84 species were sampled within the 1600 m2 study site, with numbers of species for trap diameters of: 18mm (46 species), 42mm (56 species), 86mm (62 species) and 135mm (64 species). At equal trap density, 18 mm traps caught significantly fewer species than larger traps. Traps of 86 mm and 135mm were no more efficient than 42mm traps. Only 86mm and 135mm traps caught all species > 10mm in length (6 species). For equal area of the trap mouth, small traps were more efficient than large traps. Differences in the catch of the different‐sized traps were due primarily to different capture rates of the rare species (40 species): 18mm traps caught 25% of rare species, 42 mm caught 41%, 86 mm caught 44% and 135 mm caught 52%. The role of rare ant species in environmental impact studies is discussed.
Size and structure of populations of Oedura reticulata (Reptilia: Gekkonidae) in woodland remnants: Implications for the future regional distribution of a currently common species
Authors: SARRE STEPHEN
Published: July 2006

Abstract
The gecko Oedura reticulata is restricted in distribution to the southwest of Western Australia. Within this region O. reticulata occurs mainly in smooth‐barked eucalypt woodland habitat, much of which has become fragmented by clearing. In this study, demographic characteristics of nine populations of O. reticulata that currently persist in eucalypt woodland remnants are assessed and compared with those of populations in three nature reserves. The remnants cover a range of sizes but are similar in age, tree species composition and vegetation structure. Population sizes vary considerably among remnants and are poorly correlated with remnant size or the number of smooth‐barked eucalypts. Population size does not appear to be limited by habitat availability in most remnants. The number of adults of breeding age is small in most populations suggesting that they may be susceptible to stochastic extinction pressures. The poor dispersal ability of this species between remnants means that the possibility of recolonization of a remnant following an extinction event is unlikely. As a result, the occupancy rate of O. reticulata in remnant woodland is likely to decline.
The dietary overlap between red kangaroos (Macropus rufus) and sheep (Ovis aries) in the arid rangelands of Australia
Authors: EDWARDS G. P. , DAWSON T. J. , CROFT D. B.
Published: July 2006

Abstract
The interaction between red kangaroos and sheep in the more arid areas of Australia was examined by means of a large‐scale manipulative experiment. The diets of red kangaroos and sheep grazing together and separately in large paddocks were studied to assess whether competition for food might influence diet selection in these species. Diets and the amount of intra‐ and interspecific dietary overlap varied in accordance with pasture conditions. At pasture biomasses ranging from 50 to 200 g m−2 (dry weight [wt]), the diets of red kangaroos and sheep overlapped by 58–73%, with forbs and grasses being the major items in the diets of both species. The diets of both sheep and red kangaroos under different experimental regimes were similar. In dry times (pasture biomass 40–50 g m−2 (dry wt) more shrubs were eaten by both species and the amount of dietary overlap tended to be lower (52–66%). The diets of kangaroos were similar between paddocks. However, in paddocks containing both species sheep consumed proportionately more chenopodaceous shrubs and fewer grasses than those in ‘kangaroo‐free’ paddocks.
Role of crabs in the natural regeneration of mangroves in the Sundarbans forest of Bangladesh
Authors: SIDDIQI NEAZ AHMAD
Published: July 2006

Abstract
A study in the Bangladesh Sundarbans forest observed the impact of crabs on mangrove regeneration. Crabs were not found to cause any damage to the seedlings of experimental plots. In addition, no morphological damage attributable to crabs was observed in Rhizophora propagules collected from the forest floor. Further studies covering other areas of the forests have been suggested.
2nd World Congress of Herpetology
Authors: BERVEN KEITH A.
Published: July 2006

Abstract
This study summarizes demographic data on the wood frog, Rana sylvatica, from Maryland (two populations over 7 years), Virginia (seven populations over 8 years), and Michigan (one population over 13 years). Within each geographic locality breeding adult population size was rarely stable and all populations passed through major bottlenecks. Reproductive failures (no larvae metamorphosed) were not uncommon, nor were reproductive bonanzas, where juvenile production exceeded the replacement rate by up to a factor of 6. A key‐factor analysis showed that larval mortality, in all localities, accounted for the year to year fluctuations in adult population size. However, the phase of the life cycle in which regulation occurred varied among localities. Larval mortality was strongly density‐dependent in Maryland, but only weakly so in Virginia, and not in Michigan. In Virginia and Michigan adult mortality was density‐dependent. Fecundity was density‐dependent in all three localities. Density‐independent factors also influenced population size: large fluctuations in adult population size primarily occurred due to drought‐induced catastrophic larval mortality and bacterial epidemics that dramatically affected larval survival in Virginia. Adult mortality, but not juvenile mortality, was also negatively related to precipitation levels in all localities.
Plant coexistence in coastal heaths: Floristic patterns and species attributes
Authors: MYERSCOUGH P. J. , CLARKE P. J. , SKELTON N. J.
Published: July 2006

Abstract
An investigation was made of plant coexistence in coastal heaths. A 4 km stretch of Pleistocene beach sand was selected, and patterns of variation in heath vegetation on ridges and slopes in the beach system were studied. The sampling design covered variation with geographic distance among transects, plots within transects and quadrats within plots which were orthogonal to the alignment of ridges and slopes. Cover of vascular plant species was scored within each quadrat and both multivariate and univariate analyses tested the hypothesis that variation in the data was associated with environmental difference and geographic distance. There was a strong flohstic variation between the ridge and slope habitats. However, within these habitats there was no significant variation with distance at scales of kilometres, nor at hundreds of metres within transects nor at tens of metres within plots in floristic composition, in numbers of species, and in cover. Though differing floristically, the vegetation of the slopes and ridges had similar curves of importance values and fairly similar spectra of life forms and forms of post‐fire regeneration in their constituent species, although the ridges had slightly more obligate‐seeding species and fewer species of sedges and herbs than the slopes. The two habitats shared several genera, however, within such genera, species with similar attributes mostly occurred in different habitats.

Hypotheses were suggested to explain segregation of species between the two habitats and the coexistence of species within habitats. Since patterns of variation among habitats were consistent over both smaller and larger scales of distance examined, experiments to test hypotheses may be designed so that their findings might be applied generally to the whole system studied.
Subhabitat variability: A key to the high reptile diversity in chenopod shrublands
Authors: READ J. L.
Published: July 2006

Abstract
The herpetofauna of one hectare of chenopod shrubland near Roxby Downs in arid South Australia was studied from January 1991 until June 1993. The subhabitat preferences of 27 reptile species and one frog species were investigated by analysing capture rates, from more than 1800 captures in 401 pit traps. Although the site was characterized by relatively uniform cover of the dominant plant species Atriplex vesicaria, significant variation occurred in rock cover, and in edaphic and floristic features. Ctenophorus fordi, Ctenotus brooksi and Lerista labialis were strongly associated with sandy regions while Tympanocryptis intima, Diplodactylus tessellatus and Ctenotus strauchii were largely restricted to rocky subhabitats. Ctenotus leonhardii was strongly associated with a high density of Maireana species. Subhabitat preference of some of these species could be explained by the defence strategies they employed. Several species such as Ctenophorus nuchalis, Pogona vitticeps, Tympanocryptis lineata, Diplodactylus stenodactylus, Rhynchoedura ornata, Menetia greyii and Neobatrachus centralis were subhabitat generalists within the study site. The biological appropriateness of using a smaller number of subhabitat groupings, rather than the square root of the number of study sites, was confirmed in this study. Five subhabitat groups yielded meaningful preference data for more species than did 10 or 20 groups, and did not lose resolution achieved through higher level clustering.
Habitat structure and invertebrate assemblages on stream stones: A multivariate view from the riffle
Authors: DOWNES BARBARA J. , LAKE P. S. , SCHREIBER E. S. G.
Published: July 2006

Abstract
Highly structured habitats, those with complex or heterogeneous physical structure, commonly contain more species than simply structured ones. However, tests of this relationship have been hampered by habitat‐specific definitions and measurements of habitat structure and, in stream studies, by insufficient information on spatial variation in faunal abundances. We sampled the fauna of 90 stones collected from an order 4 section of the Taggerty and Steavenson Rivers, southeastern Australia. The spatially nested sampling design encompassed three spatial scales (sites within the same stream order, riffles at the same site and groups of stones within the same riffle) but no temporal replication, as we were only able to sample once. Habitat structure of stones was quantified by measuring the amount and type of epilithon on stones, together with stone shapes, sizes, textures and surface complexities. For the latter two attributes, we used a new method, involving image analysis, which can be used to quantify habitat structure in comparable ways in other systems. Species richness (S) was related to some measures of habitat structure, being higher on stones with a rough texture and weakly related to the amount of epilithon present. Total numbers of individuals (N) were also higher on rough stones, and faunal composition (as quantified by hybrid multidimensional scaling) was related to abundance of epilithon. However, flow environments, as quantified by water velocities and depths, were also related to faunal composition. Riffles varied in both faunal densities and near‐bed flow environment, but not in any consistent way. Such variability means that individual riffles cannot be reasonably used to ‘represent’ stream sections or orders, an assumption commonly made in stream studies. Neglect of such issues has also resulted in poor conceptual integration between large‐ and small‐scale studies in stream ecology.
Munmarlary revisited: Response of a north Australian Eucalyptus tetrodonta savanna protected from fire for 20 years
Authors: BOWMAN D. M. J. S. , PANTON W. J.
Published: July 2006

Abstract
A comparison was made between the total density of tree species recorded on three 1 ha plots that have been protected from fire for 20 years, and from three surrounding sites that have been subjected to the ambient fire regime. Both unburnt plots and ambient sites were in a lowland coastal Eucalyptus tetrodonta savanna in Kakadu National Park. Fire protection resulted in a substantial increase in the number of saplings (16 times more than ambient), poles (five times more than ambient) and trees (2. 5 times more than ambient), but slightly fewer (7%) sprouts than ambient. Of the 32 species recorded in the six 0. 2 ha samples, only nine species could legitimately be analysed using Chi‐squared analysis to test for differences in the density of sprouts and saplings between unburnt and ambient samples; eight of these species had significantly different distributions. Typically the unburnt samples had a greater number of saplings compared to ambient conditions, but fewer sprouts. Eucalyptus miniata showed no significant difference in the density of sprouts and saplings between the unburnt and ambient samples. Chi‐squared analyses of the frequency distribution among four size classes (sprouts, saplings, poles and trees) was possible for six species. The results for five of these species mirrored the findings of the comparison between sprouts and saplings. However, the fan palm Livistona humilus, which typically forms a component of the mid‐layer in E. tetrodonta savannas, was found to have a large number of sprouts on the unburnt samples and a complete absence of stems in any of the other size classes. Dead L. humilus stems attested to the former occurrence of larger size classes of this species on the unburnt plots. No rainforest species were recorded in the unburnt samples. Minor differences in species composition between unburnt and ambient samples are thought to reflect sampling effects. The results of this study are consistent with the conclusions of an earlier study at the same site which also concluded that rainforest tree species do not readily colonize unburnt Eucalyptus savanna.
Plant coexistence in coastal heaths: Between‐ and within‐habitat effects of competition, disturbance and predation in the post‐fire environment
Authors: CLARKE PETER J. , MYERSCOUGH PETER J. , SKELTON NICHOLAS J.
Published: July 2006

Abstract
Previous experiments on post‐fire establishment of two obligate seeders and two resprouting species suggested that initial establishment processes differ between wet‐ and dry‐heath habitats. Disturbance, interspecific competition between seedlings and between seedlings and adults, and access for potential predators were manipulated in the field after a fire to identify mechanisms to explain between‐ and witm'n‐habitat species coexistence. When soil surfaces are disturbed or seeds are buried, dry‐heath species can establish in the wet heath. Under natural conditions, however, wet heath is rarely disturbed by animal foragers and lack of safe sites may preclude establishment of dry‐heath species. In contrast, dry heath is often disturbed by ground foragers such as bandicoots and safe sites are plentiful for establishment of all heath species. Nevertheless, while wet‐heath species can establish in dry heath, their seedlings are apparently unable to survive there due to the drier conditions. No evidence for competition among species was detected in either type of habitat during the first 3 years of the experiment, even at elevated seedling densities. Lack of early competition and unsaturated seed‐banks may promote coexistence of species. Seedling predation from vertebrates was low and did not appear to influence patterns of coexistence within or between habitats. In terms of community theory we suggest that several interacting mechanisms are responsible for community structure in heaths after a fire. Chance and microsite disturbance are important during dispersal, while resources are critical during establishment and early survival of seedling populations. In these heath systems where fires burn extensive areas, seed‐banks may be more important in temporal storage of species than patch or spatial storage as a mechanism for maintaining coexistence and plant diversity.