bluuebunny/crossref_metadata_2025 huggingface dataset:
On the nature of soil aggregate coalescence in an irrigated swelling clay
Authors: Grant C. D. , Angers D. A. , Murray R. S. , Chantigny M. H. , Hasanah U.
Published: September 2002

Aggregate coalescence in irrigated cracking clays constrains crop yields, yet
little is known about it or how it can be managed. A measure of coalescence is
introduced to separate the effects of natural aggregate-bed densification from
those of age-hardening; this measure, χ, comprises a ratio of the net
change in (tensile or penetrometer) strength, Y, that occurs in relation to
the corresponding net change in dry bulk density,
ρb, as follows: χ =
ΔY/Δρb. A laboratory study was
conducted to illustrate the variation in χ for a virgin and cultivated
cracking clay exposed to 16 weekly cycles of wetting and draining.
Penetrometer resistance and tensile strength at –100 kPa, plus bulk
density and other physical and chemical properties, were measured throughout
the experiment. The cultivated soil rapidly became denser and stronger, it
developed larger aggregates, and its water-uptake rate in the air-dry state
was significantly greater than that for the virgin soil. The χ values
suggested that age-hardening processes constituted a greater component of
coalescence in the cultivated soil than it did in the virgin one, and this was
thought to be mediated by the large differences in the content and composition
of organic matter in the two soils.
A new procedure to determine soil water availability
Authors: Groenevelt P. H. , Grant C. D. , Semetsa S.
Published: September 2002

The integral water capacity is first introduced as a flexible method to
quantify various soil physical limitations when calculating available water in
non-swelling soils. ‘Weighting’ functions that account for
hydraulic conductivity, aeration, and soil resistance to penetration are
applied to the wet and dry ends of the differential water capacity, and then
integration is performed. The concept is extended to swelling soils by
applying the theory of Groenevelt and Bolt (1972), which enables overburden
pressures to be taken into account. A set of shrinkage lines measured by
Talsma (1977) is analysed using this theory, which enables precise values of
overburden potentials to be calculated as a function of the moisture ratio for
different load pressures. The addition of the overburden potential to the
unloaded matric potential causes minor shifts in the classical limits of
plant-available water (viz. –1/3 bar and
–15 bar). However, when other soil physical restrictions are taken into
account (such as in the concept of the least limiting water range), the
consequence for available water deeper in the root-zone (due to an overburden
pressure) is far more serious. This is primarily because the matric potential
at which aeration begins to be satisfied shifts to a considerably lower value,
making a large quantity of water at the wet end no longer available. Examples
of weighting functions derived from the literature are applied and their
implications for available water in swelling soils are discussed.
Method for assessing plant-available cadmium in soils
Authors: Krishnamurti G. S. R. , Smith L. H. , Naidu R.
Published: September 2002

The suitability of several extractants was tested for assessing the
plant-available cadmium (Cd) in a few selected soils of South Australia. The
amount of Cd extracted by 7 extractants (0.01 and 0.05 M CaCl
2 , Na 2 EDTA, DTPA-TEA, M NH
4 NO 3 , AAAC-EDTA, and M NH
4 Cl) was related to the Cd concentration in the stem
and leaves of durum wheat (Triticum aestivum L. var.
Excalibur) grown in the greenhouse for 5 weeks. Soil extraction with M NH
4 Cl gave the best overall prediction of extractable Cd
with plant Cd concentration (r = 0.928,
P < 0.001) compared with the other extractants.
Multivariate models were derived to predict both the total and plant-available
Cd from the soil factors. The aqua-regia-extractable Cd was on an average
45.3% of the total Cd content, as determined by HF-HClO
4 digestion, and at best could represent the easily
extractable fraction of soil Cd. Around 77% of the variation in total
Cd content of the soils could be explained using selected soil properties,
such as free Fe, organic C, and pH. The accumulation of Cd by wheat plants
from the soils studied could be assessed using the multivariate model, log
leaf Cd = – 0.2107 + 1.2281 log Cd NH
4 Cl, with high correlation (R
2 = 0.93). The coefficient of determination could
be improved further (R 2 =
0.99) with the inclusion of the soil variables free Fe, pH, organic C, and
clay contents: log leaf Cd = 0.2095 + 1.2556 log Cd NH
4 Cl + 0.0219 Fe + 0.0149 clay – 0.2633
org. C – 0.0577 pH.
Indices of fire characteristics in sandstone heath near Sydney, Australia
Authors: Whight Sandra , Bradstock Ross
Published: September 2002

The relative sensitivity and performance of post-hocindices of fire characteristics were examined in a heathland area burnt in1994. Sites burnt at differing times before 1994 were selected andqualitatively allocated to classes of high and low crown damage. Subsequentmeasures were made of height of consumption of crowns, length of the deadportion of Xanthorrhoea resinifera leaves, and minimumtip diameters of burnt branches of the shrubs,Banksia oblongifolia andBanksia ericifolia. Results indicated that significantdifferences in mean, minimum tip diameter corresponded to contrasting classesof crown damage (larger mean tip diameters in high crown damage sites). Meanminimum branch tip diameter in B. oblongifolia was notsignificantly correlated with fuel age but significant correlations were foundwith estimates of rate of spread and Byram fire intensity at the study sites.The minimum branch tip diameter method has potential for further developmentand use as an indicator of fire intensity in heathland vegetation.
A statistical classification of Mediterranean species based on their flammability components
Authors: Dimitrakopoulos A. P.
Published: September 2002

Eight dominant Mediterranean species were classified into similar groups
according to their expected flammability, by applying multivariate statistical
methods (Hierarchical Cluster Analysis and Canonical Discriminant Analysis) on
the values of their most significant pyric properties (heat content, total and
mineral ash content, surface area-to-volume ratio, particle density). Based on
the statistical classification, meaningful explanations of the flammability
differences among individual species were deduced. The results were in good
agreement with similar rankings based on laboratory tests. Further validation
may render the method widely applicable for the assessment of species
potential flammability without laboratory flammability tests.
Benthic macroinvertebrate assemblages in five central Idaho (USA) streams over a 10-year period following disturbance by wildfire
Authors: Minshall G.Wayne , Robinson Christopher T. , Lawrence Deron E. , Andrews Douglas A. , Brock James T.
Published: September 2002

The effects of wildfire on benthic macroinvertebrate assemblages of streams in
mixed-conifer forest were examined for 10 successive years following the
Mortar Creek Fire of 1979. Changes in burned-catchment streams were evaluated
relative to a paired set of reference-catchment streams. Taxa richness and
total abundance tended to be lower in burn than in reference streams but to
converge near the end of the study; increases in the final years in both burn
and reference streams were associated with reduced flows due to drought. Total
biomass and that of the scraper, filterer, and miner functional groups usually
were greater in the burn streams. Lack of a strong relationship of
macroinvertebrate metrics with weather conditions showed that factors specific
to each stream also were influencing the biotic community. Mean among-year
Jaccard similarity was lower for burn than for reference streams. Specific
taxa responded differently to the effects of fire. Densities of
disturbance-adapted forms (e.g. Chironomidae, Baetis)
increased after the fire but not during the drought period of more stable
flows at the end of the study; many other taxa showed the opposite response.
Adverse effects of wildfire on the biotic community were largely the result of
physical changes in habitat due to increased runoff. Timing and magnitude of
effects differed widely among streams as a result of differences in stream
size, burn severity, and specific storm or snow-melt events. Though major
effects of the fire on the macroinvertebrates dissipated within 7 years,
adjustment in the habitat and biotic conditions still were taking place at the
end of 10 year and normal recovery patterns may have been obscured by the
drought.
Mapping wildland fuels for fire management across multiple scales: Integrating remote sensing, GIS, and biophysical modeling
Authors: Keane Robert E. , Burgan Robert , van Wagtendonk Jan
Published: September 2002

This paper was presented at the conference ‘Integrating spatial technologies and ecological principles for a new age in fire management’, Boise, Idaho, USA, June 1999
Fuel maps are essential for computing spatial fire hazard and risk and
simulating fire growth and intensity across a landscape. However, fuel mapping
is an extremely difficult and complex process requiring expertise in remotely
sensed image classification, fire behavior, fuels modeling, ecology, and
geographical information systems (GIS). This paper first presents the
challenges of mapping fuels: canopy concealment, fuelbed complexity, fuel type
diversity, fuel variability, and fuel model generalization. Then, four
approaches to mapping fuels are discussed with examples provided from the
literature: (1) field reconnaissance; (2) direct mapping methods; (3) indirect
mapping methods; and (4) gradient modeling. A fuel mapping method is proposed
that uses current remote sensing and image processing technology. Future fuel
mapping needs are also discussed which include better field data and fuel
models, accurate GIS reference layers, improved satellite imagery, and
comprehensive ecosystem models.
Fire modeling and information system technology
Authors: Andrews Patricia L. , Queen LLoyd P.
Published: September 2002

This paper was presented at the conference ‘Integrating spatial technologies and ecological principles for a new age in fire management’, Boise, Idaho, USA, June 1999
Fire modeling and information system technology play an important supporting
role in fuel and fire management. Modeling is used to examine alternative fuel
treatment options, project potential ecosystem changes, and assess risk to
life and property. Models are also used to develop fire prescriptions, conduct
prescribed fire operations, and predict fire behavior. Fire models and
information systems have greatly influenced fuel assessment methods. As an
example, we examine the evolution of technology used to put Rothermel’s
fire spread model into application. A review of fire and fuel modeling
terminology is given, and the relationship between fire models and fuel models
is explained. We review current fire modeling work and the influence that it
will have on fuel characterization. Finally, we discuss opportunities and
challenges involved in the use of advanced computers, the Internet, Geographic
Information Systems (GIS), and remote sensing in fire and fuel management.
Temporal simulation of diurnal temperature and relative humidity evolution at a forested mountainous site in Attica, Greece
Authors: Feidas Haralambos , Cartalis Constantinos , Lagouvardos Constantinos
Published: September 2002

Knowledge of the prevailing weather conditions regarding air temperature and humidity is critical for the definition of the Fire Weather and Fire Danger indices. In this study, two fitting algorithms were developed for the simulation of the diurnal air temperature and relative humidity cycles, using 2-hourly measurements at the forested site of Mount Parnes in Attica, Greece. Both algorithms use as input values the observed daily minimum and maximum values of air temperature and humidity to simulate the temperature and relative humidity daily cycles, respectively. In general, the algorithms provide satisfactory results especially for the three summer months (June, July and August). A 2-day prediction of the diurnal temperature and humidity cycles was also attempted using as input the temperature or humidity data of the previous days in the area of interest. The prediction may be considered satisfactory for the three summer months and less satisfactory for May and September due to weather instability. Finally a dynamic model was also used for supporting the performance of the developed algorithms, especially in the event of sudden weather changes.
Soil organic matter and aggregates affected by wildfire in a Pinus halepensis forest in a Mediterranean environment
Authors: Mataix-Solera J. , Gómez I. , Navarro-Pedreño J. , Guerrero C. , Moral R.
Published: September 2002

Three Mediterranean soils located in the north of the Province of Alicante (Spain) were studied for a year after a forest fire. The percentage of water-stable aggregates (between 0.2 and 4 mm) and organic matter content were measured. Microaggregates (< 0.2 mm) were observed using electron microscopy. The results showed the importance of type of forest fire on soil organic matter and aggregates. Soil structure was more affected by surface fire (which affects mainly brushwood and soil surface) than crown fire (which burns the tops of trees and some brushwood). Accumulation of organic matter from burnt trees and brushwood in areas affected by crown fire and alterations in organic matter content through the soil profile were observed. Surface forest fire affected soil structure more negatively than crown fire as observed using electron microscopy. Soils affected by surface fire may be more easily eroded and recovery of vegetation may be delayed because of effects on soil structure. Organic matter content through the soil profile comparing burnt and adjacent unburnt soil could be used to determine the type of fire.
The effect of habitat type and seasonal conditions on fauna in two areas of the Tanami Desert
Authors: Paltridge Rachel , Southgate Richard
Published: September 2002

Australian deserts are characterised by highly patterned plant productivity
and an extremely unpredictable climate. The Tanami Desert in central Australia
is dominated by vast sandplains interspersed with more productive habitats
such as palaeodrainage lines. During 1996 and 1997 fauna surveys were
conducted in two areas of the Tanami Desert to investigate the relative
importance of palaeodrainage habitat for fauna under different seasonal
conditions. The two areas were at latitudes separated by approximately 400 km,
and during the study period the northern study area (Tennant) received
considerably more rainfall than the southern study area (Kintore). The species
richness and abundance of a range of taxonomic groups were compared between
the two study areas and between palaeodrainage habitat and adjacent sandplain
habitat. The only significant difference between habitats was that small
reptiles were more abundant in sandplain than palaeodrainage habitat. Overall,
bilbies, bustards and macropods were significantly more abundant at Tennant
than Kintore, but significantly more small mammals were captured at Kintore.
In both habitats and areas, capture rates, track counts and species richness
of reptiles varied significantly with season. The biomass of invertebrates
captured also showed significant temporal fluctuations. Burrowing frogs were
active only after rain, and birds showed significant fluctuations in abundance
and species richness associated with rainfall. The abundance of small mammals
did not vary significantly during this study. Overall, local seasonal
conditions were generally more important determinants of the abundance of
fauna in the spinifex grasslands of central Australia than was habitat type.
Habitat and diet of the dibbler (Parantechinus apicalis) on two islands in Jurien Bay, Western Australia
Authors: Bencini Roberta , McCulloch Callum , Mills Harriet R. , Start Antony N.
Published: September 2002

Trapping was conducted over three years on Boullanger and Whitlock Islands in
Jurien Bay (Western Australia), to establish the habitat and diet of the
dibbler (Parantechinus apicalis), an endangered
marsupial. Habitat preference was determined by conducting a single-factor
ANOVA of the trapping success rate for P. apicalis
captured at each trap site. The diet was investigated by scat analysis. On
Boullanger Island there was no significant difference between trapping success
rate in the different habitats. However, on Whitlock Island, significantly
greater trapping success rates were recorded in the dunal scrubland dominated
by Nitraria billardierei and foredune heath than in
succulent heath. Scats contained arthropod (65%) and some vegetable
(25%) matter, confirming that island P. apicalis
are chiefly insectivorous and rarely eat vertebrate prey.
Population dynamics of three species of dasyurid marsupials in arid central Australia: a 10-year study
Authors: Dickman Christopher R. , Haythornthwaite Adele S. , McNaught Gayle H. , Mahon Paul S. , Tamayo Bobby , Letnic Mike
Published: September 2002

This study investigated the population dynamics of three species of dasyurid
marsupials in sand ridge habitat of the Simpson Desert, western Queensland,
over a 10-year period between March 1990 and December 1999. The lesser
hairy-footed dunnart (Sminthopsis youngsoni), was
captured most consistently over the period of study, followed by the wongai
ningaui (Ningaui ridei), and the mulgara
(Dasycercus cristicauda). Rates of recapture were low
(4.5–22.2%), probably because individuals of each species are
very mobile. All species bred in late winter or early spring when animals were
aged at least 8–10 months, and independent juveniles first appeared
usually in summer. S. youngsoni reared a second litter
in late spring or early summer in 3 of the 10 years studied, when the
availability of food was likely to have been high; neither
N. ridei nor D. cristicauda were
known to attempt a second litter within a season.
To explore factors that might influence population dynamics, we compared
capture rates of each species with measures of rainfall, temperature,
vegetation cover, abundance of predators [feral cats
(Felis catus), red foxes
(Vulpes vulpes), and goannas
(Varanus spp.)], dragons, other dasyurids and
indices of food abundance. The abundance of S. youngsoni appeared to depend
primarily on the cover of spinifex 7–9 months earlier, that of
D. cristicauda was related most strongly to rainfall
7–9 months earlier, while that of N. ridei was
related to minimum temperature lagged by 1–3 months.
While the dynamics of other arid-zone mammals are driven demonstrably by
interactions between rainfall, resource availability and predation, our
findings suggest that dasyurids have limited flexibility in their life
histories and are influenced more subtly and by factors such as facilitation
that are just beginning to become apparent.
The distribution and abundance of ground-dwelling mammals in relation to time since wildfire and vegetation structure in south-eastern Australia
Authors: Catling P. C. , Coops N. , Burt R. J.
Published: September 2002

Vegetation undergoes a natural succession after wildfire. Following an initial
flush of vegetation, when light and other resources become limiting, the stand
structure rapidly reaches a maximum. As a result, vegetation structure does
not form an even distribution over the landscape, but rather a patchwork
pattern. The position and characteristics of a patch of habitat in the
landscape may be critical in determining the faunal composition. In this paper
a sequence of ‘habitat complexity scores’ (which describe
vegetation structure independently of plant species) collected over 20 years
following a wildfire was utilised to estimate vegetation structure in relation
to time since fire. This information was compared with data collected over the
same period on medium-sized and large grounddwelling mammals to examine the
response of mammals to changes in vegetation structure. Models are presented
of the response of ground-dwelling mammals to time since wildfire and to
changes in habitat complexity scores, with predictions up to 25 years after
wildfire.
The ecology of an Australian reptile icon: how do blue-tongued lizards (Tiliqua scincoides) survive in suburbia?
Authors: Koenig Jennifer , Shine Richard , Shea Glenn
Published: September 2002

Although most species of large reptiles in the Sydney region are now
restricted to remnant bushland, the blue-tongued lizard
(Tiliqua scincoides) remains abundant. How has this
large, slow-moving reptile managed to persist in the suburbs? We implanted
radio-transmitters into 17 adult blue-tongued lizards and tracked them for six
months (October 1998 to March 1999). Radio-tracked animals utilised 5–17
suburban backyards, but each lizard spent most of its time in a few
‘core’ areas near 2–7 shelter sites. Males had larger home
ranges than females (mean of 12700 v. 5100 m
2 ) and moved further between shelter sites. Gravid
females (mean home range 1000 m 2 ) were more sedentary.
Lizards used corridors of dense vegetation to move between retreat sites, and
actively avoided crossing roads. In sunny weather, lizards typically basked
close to their overnight shelter for 1–4 h each morning until they
obtained body temperatures of approximately 32°C. They maintained high
body temperatures while moving about in the afternoon.
In combination, the following ecological factors may facilitate persistence of
blue-tongued lizards at our suburban study sites. (i) The most important
subgroup of the population in terms of conservation are gravid females, which
are highly sedentary and, thus, less likely to encounter the dangers of
suburbia. (ii) The more ‘expendable’ males move about much more,
but mostly in times and places that involve minimal risk from humans and their
domestic pets. (iii) Lizards show strong site fidelity, spending up to
70% of their time in ‘safe’ locations; importantly, they
avoid roads. (iv) Blue-tongued lizards readily utilise
‘artificial’ shelter sites and the commensal prey species (e.g.
snails) found in most gardens. (v) These lizards can grow rapidly, mature
early, and produce large litters. Because blue-tongued lizards have a long
life span (over 30 years in captivity), populations of adults may persist for
many years in the absence of recruitment.
Retention of the bait marker Rhodamine B in wild house mice
Authors: Jacob J. , Jones D. A. , Singleton G. R.
Published: September 2002

We investigated the retention of the systemic bait marker Rhodamine�B (RB) in house mice (Mus domesticus) that were fed RB in pellet bait (0.5% RB) and in water solutions (1.6%). Wild mice fed RB baits (3 mg RB) or provided with treated water (0.3 mg RB) were screened for traces of RB in whiskers, blood, urine, faeces, and the digestive tract. The dye was detectable in all tissues and excretions tested 12 h after its uptake in pellet bait or solution. RB was detectable under ambient light in urine and the digestive tract for up to four days and in faeces for up to two days. RB was detectable in blood sera for up to 84 h using a fluorometer. RB-bands were found in whiskers for up to seven weeks after ingestion of RB. There was no difference between males and females regarding the presence of RB in blood and whiskers. A second dose of RB (1.8 mg) one week after the first dose resulted in two bands in mouse whiskers. Fewer mice were scored RB positive when uptake of RB was low. In contrast to whiskers, analysis of blood sera provided quantitative results and allowed rapid screening of animals. We conclude that RB is an appropriate marker for short- and medium-term studies on bait uptake in house mice.
The rodents of South Australia
Authors: Robinson A. C. , Kemper C. M. , Medlin G. C. , Watts C. H. S.
Published: September 2002

Thirty species of rodents are recorded from South Australia. At the time of
European settlement, the State probably supported at least 19 species of
native rodents. Eight additional species have been recorded only in subfossil
material. At least 11 species are now considered to be extinct and there have
been significant declines in all the other species as a result of over 150
years of European influence. In addition, three species have been introduced
to the State since European settlement. Over the last ten years, there has
been a significant increase in our understanding of the distribution and
ecology of what remains of the rodent fauna through a series of systematic,
site-based biological surveys, a significant increase in research on subfossil
and owl pellet remains, documentation of Aboriginal ecological knowledge and
ecological and distributional studies on three species. This paper describes
our current state of knowledge of the distribution, ecology and threats to the
South Australian rodent fauna and makes suggestions for future research and
conservation management.
Status and conservation of the rodents of Tasmania
Authors: Hocking Gregory J. , Driessen Michael M.
Published: September 2002

Compared with mainland Australia the diversity of rodents in Tasmania is low.
In all, there are five species of native rodent in Tasmania. Three species
– the water rat, Hydromys chrysogaster, the
long-tailed mouse,Pseudomys higginsi and the swamp rat,
Rattus lutreolus – are widely distributed. The
broad-toothed rat, Mastacomys fuscus, is restricted to
moorlands in western Tasmania, while the New Holland mouse,
Pseudomys novaehollandiae, is restricted to coastal
heath in north-eastern Tasmania and is listed as Rare under Tasmania’s
Threatened Species Protection Act 1995. Only one species,
Pseudomys higginsi, is endemic to Tasmania.
Rattus lutreolus velutinus and
Mastacomys fuscus fuscus are endemic subspecies. In
addition to the native rodents, three species of exotic rodents are well
established in Tasmania.
Dietary adaptation of reintroduced yellow-footed rock-wallabies, Petrogale xanthopus xanthopus (Marsupialia : Macropodidae), in the northern Flinders Ranges, South Australia
Authors: Lapidge Steven J.
Published: September 2002

Adaptation in the diet of captive-bred
yellow-footed rock-wallabies
(Petrogale xanthopus xanthopus) was assessed following
their release into Aroona Dam Sanctuary within the species’ former range
in the northern Flinders Ranges. Dietary analysis by means of microscopic
examination of fresh faecal pellets was carried out prior to the
animals’ release in September 1996 and then at monthly intervals for
three months. Concurrently, the diets of animals in the two closest extant
colonies of P. x. xanthopus were examined for
comparison. Site vegetation and dietary components were classified into five
categories: grasses, forbs (herbaceous species), chenopods (both flat- and
round-leaved), browse (woody shrubs and trees) and plants with stellate
trichomes (including
Ptilotus, Solanum, Sida, and Abutilon spp.). Grasses
(61%) and forbs (33%) constituted 94% of the diet of the
captive-bred animals prior to release. Grass consumption declined to
51% at one month after release, while intake of browse increased from
4% to 13%. Intake of grass and forbs continued to decline over
the next three months as seasonal conditions became generally warmer and
drier. Plants with stellate trichomes (mainly
Sida petrophila and Ptilotus obovatus) appeared in the
diet at a frequency well above their relative availability, constituting
20% of the dry-weight dietary intake two months after release. Similar
selectivity for plants with stellate trichomes was also found among wild
populations at the two occupied sites.
The influence of time since fire and distance from fire boundary on the distribution and abundance of arboreal marsupials in Eucalyptus regnans-dominated forest in the Central Highlands of Victoria
Authors: van der Ree R. , Loyn R. H.
Published: September 2002

The impact of time since fire after two consecutive wildfires 44 years apart (1939 and 1983) within the same area, and the distance from the fire boundary (<100 m or 500-2000 m), were investigated in relation to the distribution and abundance of arboreal marsupials in 1994. Arboreal marsupials were censused by stagwatching and spotlighting in two relatively young age classes of mountain ash (Eucalyptus regnans) dominated forest in the Central Highlands of Victoria. Five species of arboreal marsupial were detected, but only three were detected in sufficient numbers to determine habitat preferences. Petauroides volans (greater glider) was statistically more abundant in 1939 regrowth forests, while Trichosurus caninus (mountain brushtail possum) showed no significant preference for either age class of forest. All but one record of Gymnobelideus leadbeateri (Leadbeater's possum) came from young forest, though the effect of age-class was not statistically significant. Distance from fire boundary explained little or no variation in mammal distribution or abundance. While the actual number of hollow-bearing trees was similar in both age classes of forest, the long-term lifespan of hollow-bearing trees in more recently burnt forest is predicted to be lower than in unburnt or not recently burnt forest. Post-fire salvage logging following the 1983 wildfires appears to have reduced the number of hollow-bearing trees at sites burnt in 1983.
An assessment of the introduced mosquitofish (Gambusia affinis holbrooki) as a predator of eggs, hatchlings and tadpoles of native and non-native anurans
Authors: Komak Spogmai , Crossland Michael R.
Published: September 2002

The introduced mosquitofish
(Gambusia affinis holbrooki) is a pest species in
Australia and has been implicated in the decline of populations of native
fishes and anurans. However, few quantitative data exist regarding
interactions between Gambusia and native aquatic fauna.
We used replicated laboratory experiments to investigate predation by
G. a. holbrooki on eggs, hatchlings and tadpoles of
native (Limnodynastes ornatus) and non-native
(Bufo marinus) anurans. Our aims were to determine (1)
whether the susceptibility of anurans to predation by
G. a. holbrooki changes during larval development, and
(2) the potential for G. a. holbrooki as a predator of
the introduced toad B. marinus. Gambusia were
significant predators of all aquatic life-history stages of
L. ornatus, but were significant predators of
B. marinus only at the hatchling stage. When offered
both species simultaneously, Gambusia consumed tadpoles
of L. ornatus but avoided those of
B. marinus. The differences between the responses of
Gambusia to L. ornatus and
B. marinus are probably due to differences in
palatability and toxicity of eggs, hatchlings and tadpoles of these species.
The results indicate that G. a. holbrooki is unlikely to
significantly affect larval populations of B. marinus
via predation. However, Gambusia has the potential to
significantly affect larval populations of L. ornatus in
natural water bodies where these species co-occur.
The effect of forearm bands on insectivorous bats (Microchiroptera) in Australia
Authors: Baker G. Barry , Lumsden Lindy F. , Dettmann E. Belinda , Schedvin Natasha K. , Schulz Martin , Watkins Doug , Jansen Loraine
Published: September 2002

We assessed injuries to the forearms of 17 species of microchiropteran bats
marked for ecological studies and banded under the auspices of the Australian
Bird & Bat Banding Scheme. Serious injuries were recorded in 16 of the 17
species, but injury rates varied between species according to band type, band
size and metal type. Survival estimates were calculated for three species. In
Nyctophilus geoffroyi mean annual survival was
significantly lower for animals marked with bat bands that caused major
injuries to 7.1% of recaptured animals than that for animals marked
with bird bands that produced negligible injury rates. The results of this
study have led the Australian Bird & Bat Banding Scheme to adopt a
precautionary principle and impose a moratorium on the banding of bats
belonging to the families Vespertilionidae, Molossidae and Emballonuridae.
Applications to band microchiropteran bats are now considered on a
case-by-case basis. Rigorous trials on target species are required to evaluate
the efficacy of the marking technique proposed before banding approval is
granted. Banding of potentially sensitive species is limited to studies in
which the impacts of banding can be evaluated directly, such as at known roost
sites. There is a need to develop alternative methods for marking
insectivorous bats for ecological studies of wild populations.
Evaluation of line-transect sampling to estimate nocturnal densities of macropods in open and closed habitats
Authors: le Mar K. , Southwell C. , McArthur C.
Published: September 2002

Walked line transects were evaluated for estimating nocturnal densities of
red-necked wallaby (Macropus rufogriseus) and the
red-bellied pademelon (Thylogale billardierii) in a
range of open and closed habitats. The use of cleared transect lines in
densely vegetated habitats reduced noise produced by travelling, while
permanent grid markers facilitated collection of perpendicular distance data
at night. Results from sighting histograms indicated that animals did not
display evasive movement in response to the observer before detection. The
probabilities of detecting the macropod species varied significantly between
habitats. Significant differences in probabilities of detection were also
recorded within species between habitats. Consequently, line-transect sampling
is recommended over strip-transect sampling for estimating species abundance
when more than one species and/or habitat are of interest. Recommendations
are made, however, for forest managers wanting to monitor macropod populations
on newly established plantations, when line-transect sampling is not feasible
and strip-transect sampling is the only alternative.
A simple model for ferret population dynamics and control in semi-arid New Zealand habitats
Authors: Barlow N. D. , Norbury G. L.
Published: September 2002

Introduced ferrets (Mustela furo) in New Zealand are
subject to population control to reduce their threat to native fauna and the
incidence of bovine tuberculosis (Tb) in livestock. To help in evaluating
control options and to contribute to a multi-species model for Tb dynamics, a
simple Ricker model was developed for ferret population dynamics in a
semi-arid environment. The model was based on two data sets and suggested an
intrinsic rate of increase for ferrets of 1.0–1.3
year–1 and a carrying capacity of 0.5–2.9
km–2. There was evidence for direct
density-dependence in both data sets and the effect appeared to act mainly on
recruitment. Dependence of the rate of increase of predators on the density of
wild rabbits (Oryctolagus cuniculus) was exhibited in
one of the two data sets, together with a numerical response relating current
density of predators asymptotically to current density of rabbits, their
primary prey. Predators in this data set included both cats and ferrets,
estimated from spotlight counts, but the other data set demonstrated a direct
proportionality between predator (cat and ferret) spotlight counts and minimum
ferrets known to be alive by trapping. The model suggested, firstly, that
populations are hard to suppress by continuous culling, with at least a
50% removal per year necessary to effect a suppression of 50% in
long-term average density. Secondly, if control is episodic rather than
continuous, culling in autumn gives a greater degree of suppression over time
(280%, accumulated over time) than culling in spring (180%). A
differential equation version of the model provides a component for a general
Anderson/May bovine Tb/wildlife (possum/deer/ferret) model.
An intraspecific and interspecific comparison of raptor diets in the south-west of the Northern Territory, Australia
Authors: Aumann Tom
Published: September 2002

Dietary information, collected during 1995–97 in the south-west of the
Northern Territory, is presented for 11 raptor species. Unlike better-studied
populations of these species in south-eastern and eastern Australia, most of
the raptors in the arid inland were found to depend heavily on reptiles and
birds, the budgerigar (Melopsittacus undulatus) being a
particularly important food for many species during those periods when it was
plentiful. Between-territory, between-year and seasonal differences in diet
are quantified for most species.
The raptor assemblages in central Australia included specialists on
medium-sized to large mammals, small to medium-sized birds, and small
reptiles/invertebrates, as well as several generalists. Indices of prey
diversity and evenness were calculated for each species, and diet overlap
between them was used to investigate aspects of interspecific competition for
food. Overall, diet overlap was greatest among the bird specialists and
between some of the generalists. It increased in 1997, a year of comparative
plenty, possibly because several species exploited an abundance of some prey
taxa and competitive pressure eased.
Effects of tropical rainforest roads on small mammals: inhibition of crossing movements
Authors: Goosem Miriam
Published: September 2002

Along a narrow, unsealed road through rainforest in north-eastern Queensland,
movements of small mammals were examined to determine whether the road would
inhibit road crossings, thereby causing linear barrier effects. Crossings of a
12- or 20-m-wide road clearing by Melomys cervinipes
were severely inhibited, crossing inhibition of Rattus
sp. was less severe, while crossings by
Uromys caudimaculatus were unaffected. This differential
effect was attributed to species differences in size, mobility and behaviour.
Baiting on only one side of the road increased crossing rates for all species.
During the breeding season, crossings of 20-m clearings by
Rattus sp. were almost completely inhibited and were
significantly fewer than crossings of 12-m clearings. Clearing width had
little effect on crossing rate outside the breeding season. Seasonal dispersal
of juvenile and breeding animals appeared to explain this discrepancy in
clearing-width effects. Rattus sp. were significantly
less likely to cross a road where there was no vegetative cover at the
entrance to a road culvert than where there was cover at both culvert
entrances. Linear barrier effects for small mammals may be mitigated by
narrower road-clearing widths, by replanting of grassy road verges resulting
in increased cover at culvert entrances and canopy closure above the road, and
by providing more faunal underpasses.
The eastern horseshoe bat, Rhinolophus megaphyllus, in south-east Queensland, Australia: colony demography and dynamics, activity levels, seasonal weight changes, and capture-recapture analyses
Authors: Young R. A.
Published: September 2002

During this study, 634 eastern hoseshoe bats,
Rhinolophus megaphyllus, were captured at three colonies
in south-east Queensland, with most data coming from two colonies (Anjuramba
mine and Ravensbourne cave). Colony size, sex ratios, age structure, and
colony function varied between colonies and with season.
Capture–recapture data of banded bats was used to monitor movement
patterns, seasonal weight changes, colony-size estimates at Anjuramba (JOLLY
model), and the recapture frequency according to sex and age. The JOLLY
estimator of the population size over-estimated the actual population at
Anjuramba on most occasions but paralleled changes in population size. Of the
319 bats banded, 21.9% were recaptured, with only one recovery
involving a movement between roosts. Adult males have a high roost-site
fidelity and are more sedentary than adult females. The recapture rate and
recapture frequency for adult males was significantly higher than for adult
females. R. megaphyllus is active throughout the year
but may enter torpor for short periods, with more females than males observed
in torpor. There was no significant association between torpor and season.
Longevity records of 7 years and 1 month were recorded for a sub-adult female
and 7 years and 7 months for a juvenile female.
Kullback-Leibler information as a basis for strong inference in ecological studies
Authors: Burnham Kenneth P. , Anderson David R.
Published: September 2002

We describe an information-theoretic paradigm for analysis of ecological data,
based on Kullback–Leibler information, that is an extension of
likelihood theory and avoids the pitfalls of null hypothesis testing.
Information-theoretic approaches emphasise a deliberate focus on the
a priori science in developing a set of multiple working
hypotheses or models. Simple methods then allow these hypotheses (models) to
be ranked from best to worst and scaled to reflect a strength of evidence
using the likelihood of each model
(gi), given the data and the
models in the set (i.e.
L(gi
| data)). In addition, a variance component due
to model-selection uncertainty is included in estimates of precision. There
are many cases where formal inference can be based on all the models in the
a priori set and this multi-model inference represents a
powerful, new approach to valid inference. Finally, we strongly recommend
inferences based on a priori considerations be carefully
separated from those resulting from some form of data dredging. An example is
given for questions related to age- and sex-dependent rates of tag loss in
elephant seals (Mirounga leonina).
Oestrous cycle and gestation length in the musky rat-kangaroo, Hypsiprymnodon moschatus (Potoroidae : Marsupialia)
Authors: Lloyd Shan
Published: September 2002

Wild-caught male and female H. moschatus were maintained
in a captive breeding colony. Vaginal smears were taken three times a week
until oestrous cycles were detected and gestation lengths approximated.
Thereafter, smears were usually taken daily when oestrus was expected. The
gestation period (considered to be the number of days from the detection of
sperm in the smear until the day young were found in the pouch) was found to
last 19 days. Sperm were usually detected in the smear two days before the
influx of semi-cornified and cornified epithelial cells, which occurred 17
days before parturition. A pre- or post-partum oestrus was not detected and
females did not return to oestrus until at least 6 days after the removal of
the last pouch young.
H. moschatus has the shortest recorded gestation for any
macropod, and gestation occupies approximately 75% of the oestrous
cycle. The reproductive physiology of H. moschatus is
similar to that of most phalangerids, which may be indicative of a common
ancestor.
Monitoring the oestrous cycle of the chuditch (Dasyurus geoffroii) (Marsupialia : Dasyuridae): non-invasive analysis of faecal oestradiol-17b
Authors: Stead-Richardson E. J. , Bradshaw S. D. , Bradshaw F. J. , Gaikhorst G.
Published: September 2002

Faecal oestradiol-17β levels were monitored for three months during the
breeding period in six female chuditch
(Dasyurus geoffroii) held in a captive colony. Four of
the females mated and gave birth to young. One female mated once but did not
conceive and the other female did not mate. Peaks in oestradiol concentration,
up to 9 ng g–1 of dried faecal mass, were observed
during the period when urogenital swabs were dominated by cornified epithelial
cells. Multiple peaks of oestradiol were also observed in the female that did
not mate, suggesting that the chuditch may be a reflex ovulator. Monitoring of
faecal oestradiol levels did not enable oestrus to be determined with
precision, but showed potential for elucidating details of the reproductive
biology of this and other marsupial species.
The phylogeny of the stomatopod Crustacea
Authors: Ahyong Shane T. , Harling Christine
Published: September 2002

The stomatopods, or mantis shrimps, are malacostracan crustaceans of the
subclass Hoplocarida. Extant hoplocarids belong to the order Stomatopoda and
suborder Unipeltata, comprising the extinct, stem-lineage pseudosculdids and
sculdids, and the crown group. Cladistic analysis including most or all genera
of the unipeltatan families, and rooted to the extinct Tyrannophontidae,
resulted in four most-parsimonious cladograms. The present results are more
highly resolved and more robust than previous studies as the result of: more
precise identification of suitable outgroups; a more complete outgroup data
set, lessening the impact of missing data; and increased taxonomic sampling.
The results largely support the existing five-superfamily classification, but
as with two recent cladistic studies, Gonodactyloidea was polyphyletic.
Gonodactyloidea is the basal crown-group superfamily and comprises mostly
‘smashers’. Two clades of ‘spearers’, Eurysquillidae
and Parasquillidae, previously considered gonodactyloids, are more closely
related to the Squilloidea and are referred to new superfamilies. The familial
classification within Lysiosquilloidea is modified. Rather than deriving the
‘smashers’ from a long line of ‘spearers’, the present
analysis suggests that the Unipeltata diverged in two broad directions from
the outset. Hence, the gonodactyloid ‘smashers’ became specialised
for hard substrates, and the remainder diversified into the other modern
superfamilies, evolving more efficient ‘spearing’ claws, and
occupying soft substrates.
Opportunistic breeding in the polyandrous honey possum, Tarsipes rostratus
Authors: Wooller R. D. , Richardson K. C. , Garavanta C. A. M. , Saffer V. M. , Bryant K. A.
Published: September 2002

Honey possums, Tarsipes rostratus, tiny (7–12 g)
flower-dependent marsupials, were trapped in three areas of south coastal
heathland in Western Australia on 5–8 occasions each year from 1984 to
1995. Mark–recapture estimated annual mortality at 86%, with only
a few individuals living for more than one year. Most females breed for the
first time while not yet fully grown and may produce up to four litters in a
year. Maximal litter size is four, but usually only two or three young are
reared. The small litter size and relatively slow growth of pouch young is
attributed to the time needed for the mothers to harvest pollen, upon which
T. rostratus relies for its nitrogen requirements.
Females with pouch-young were recorded in all months, but with a higher
frequency over winter when nectar was most abundant, and at a lower frequency
(in some years, none) when food was scarce in autumn. Young are in the pouch
for about 60 days and some females give birth to the next litter soon after
pouch exit, presumably from delayed blastocysts. We suggest that
T. rostratus females are polyandrous and that the
smaller males compete by searching for females in oestrus. The multiple
paternity of several litters, confirmed by single-locus microsatellite
profiling, supports this model.
Reproduction in the squirrel glider, Petaurus norfolcensis (Petauridae) in south-east Queensland
Authors: Millis A. L. , Bradley A. J.
Published: September 2002

Reproduction was studied across a three-year period in two south-east
Queensland populations of the squirrel glider,
Petaurus norfolcensis, by measuring morphological (body
weight, scrotal diameter, cutaneous scent-gland activity, condition index) and
physiological (plasma steroid levels) variables. Reproduction showed a
seasonal pattern, with peak numbers of pouch young recorded in late autumn and
winter. Declines in oestrogen concentrations outside the breeding period
indicate that females are anoestrous in the summer months. Most (83%)
reproductive females captured during the study were 2–3 years old, but
all individuals over one year of age were found to have bred. Average litter
size was 1.73 ± 0.01 (n = 23).
Scrotal diameter and testosterone concentrations showed no significant
seasonal variation. It is suggested that this is due to the presence of both
socially dominant and subordinate males in the data set. Maximum testosterone
concentrations did coincide with periods of mating. The condition index showed
no relationship with reproductive variables, but it is likely that this
results from the manner in which the index was generated.