1999 Research
reports
- Events
and outcomes of Open Day 1999
- Determinants
of Reproductive Success in female Red Kangaroos.
- Feeding
ecology, nesting behaviour and nest-site selection of the wedge-tailed
eagle.
- Red
kangaroos and Eastern Grey Kangaroos in the arid rangelands:
Factors impacting on water use.
- Vegetation,
hydrology, and erosion mechanisms in arid zone streams and shrublands
The
Western NSW Archaeological program (WNSWAP) at Fowlers Gap
- Using In-Situ-Produced Cosmogenic Isotopes to Understand the
Formation of Stone Pavements and Aeolian Deposited Soils at
Fowlers Gap, North Western New South Wales.
- The
effect of sheep grazing on lizard assemblages in the NSW arid
zone.
- Digestive
limitations and maintenance energy and nitrogen requirements
of juvenile red kangaroos (Macropus rufus)Digestive limitations
and maintenance energy and nitrogen requirements of juvenile
red kangaroos (Macropus rufus)
- Acquisition
and analysis of rainfall data from Fowlers Gap
Reporter: Ben Macdonald, School of Geography,
UNSW
The School of Geography organised
an Open Day at the Fowler’s Gap Field Station on July 16th 1999, and the venue was the shearing shed. A selection of the
papers has been published in volume 21 of the Rangeland Journal
and these reflect the wide nature of research at Fowler’s Gap.
It was the organiser’s intention to invite papers from a wide
field to highlight the varied research at the Station and provide
cross-disciplinary discussion. Some of the papers are not specifically
based at Fowler’s Gap but all of the researchers have started
their original research at the Station and have applied it to
a broader area. The theme of the Open Day was “the understanding
and application of sustainable use of rangeland resources in Australia”.
A key objective was to promote the research at the Station to
the local graziers and landholders because it is the users and
inhabitants of the rangelands who need the rangeland management
information to care for the land.
The Open Day was very successful.
It drew approximately 130 people from the surrounding area, including
a student group from each of the University of New South Wales
and Monash University, various government departments, graziers
and other interested landholders. Question time after the presentations
was always stimulating and there was a large exchange of information
between participants, which is typically sadly lacking at other
conferences. Quality and variety of the papers presented at the
symposium and the selected papers published in the Rangeland Journal
show that the University of New South Wales Fowler’s Gap Research
Station is still a cornerstone in rangeland research. This proves
that the academics and administrators who believe that there is
no more scope for research at Fowler’s Gap are well wide of the
mark.
Investigators: Amanda Bilton and David Croft, School of Biological Science, UNSW
Essential for effective population
management is knowledge of the factors that affect female reproductive
success and subsequently the recruitment of offspring to the next
generation. Currently, the Red Kangaroo is subject to a commercial
harvest (15-30% of the population), the management of which fails
to take into account the current over-hunting of certain age/sex
classes (up to 80% male), and the effect of adverse environmental
conditions on specific age/sex classes. By examining the level
and causes of variation in reproductive success among these animals,
this project will provide a more comprehensive understanding of
population composition and dynamics, and the application of the
results to kangaroo management will be vital to the process of
ensuring the sustainable harvest of this species.
Specifically I am looking to determine
the effect on reproductive success of: maternal quality, including
age, body condition, maternal care and social rank; sex of the
offspring; quality and biomass of vegetation in the home range;
and the density of conspecifics and other mammalian herbivores
in the habitat.
Results so far suggest that environmental
conditions, in particular, rainfall and the abundance of good
quality feed, in this case green grass, have a significant impact
on the survival of young to weaning. It was found that those females
that successfully reared their offspring to weaning were doing
so at times when the amount of green grass available in the habitat,
and the rainfall over that period, was significantly higher than
for those females that lost their offspring. Given the highly
dependant relationship between rainfall and plant growth in the
semi-arid regions of Australia, and the high energy and nutrient
requirements of growing young, it fits that the survival of the
young is greatest during times of relatively good pasture conditions.
Sex of the offspring also seems to
play an important role in the scheduling of maternal reproductive
effort. Those mothers weaning male offspring were significantly
older than those weaning female offspring, a life-history trait
also observed in the Eastern Grey Kangaroo. Also, those mothers
successful at rearing male offspring to the stage of permanent
pouch exit, 8 months, were doing so at times when there was significantly
more green grass available in the habitat compared to those mothers
rearing females. These results suggest that females may manipulate
their investment in male or female offspring according to the
relative costs and benefits of rearing the different sexes. Continuing
work on maternal care and behaviour will hopefully elucidate to
what degree the sex of a mother’s young may affect her life-time
reproductive success.
Field work began in March 1998 and is due for completion
by March 2001.
Investigators: Lisa Collins and David
Croft, School
of Biological Science, UNSW
An Honours thesis was produced from
the research in 1999 under the title ' Factors influencing chick
survival in the Wedge-tailed eagle, Aquila audax' with
the following abstract.
Offspring survival is an important
part of the population dynamics of every species. Chick survivorship
in the wedge-tailed eagle, Aquila
audax, was studied with reference to nest quality and parental
quality. Nest quality included nest and tree characteristics,
nest location with regard to local prey densities and the nest
environment with regard to adverse sibling interactions. Parental
quality included the proportion of time the parents were present
at the nest and the behaviours they performed as well as the quantity
of food presented to the chick and the composition of the chicks
diet. The study site was at Fowlers Gap Arid Zone Research station
in north-western New South Wales. Five nests were monitored with
three out of the seven chicks known to hatch surviving to fledge.
Nest and tree characteristics did not appear to influence chick
survivorship. Prey surveys were performed every month over the
study period and sightability of prey items was tested between
nest sites by ANOVA with no difference found. Rabbit warrens were
surveyed intensively to a 200 m radius around each nest and their
abundance calculated by the regression equation y=0.707+0.355x.
The abundance of prey animals was analysed by ANOVA with respect
to nest success and the time at which the transects took place.
No significant effect was found. Parental care-giving behaviours
decreased with increasing age of the chick as did the amount of
time a parent was at the nest relating to an increasing ability
of the chick to thermoregulate and feed itself. Bearded dragons
were the main prey item delivered and fed to the chicks. The number
of feeds given by the parent decreased with chick age and was
found to correlate with the number of feeds of bearded dragon.
Siblicide caused the death of one chick while another died due
to infanticide. In another nest one chick fell out and the other
died from unknown causes overnight. The failure of the unsuccessful
nests early in the study resulted in a lack of data on parental
behaviour for these nests leaving only the prey surveys and nest
characteristics to be compared.
Further monitoring of fledging success
in these eagles will be undertaken in 2000.
Return to index
Investigators: Terence Dawson, Kirsten McTavish, Adam Munn, Joanne
Holloway and Beverley Ellis, School
of Biological Science, UNSW
Red
kangaroos (Macropus rufus)
occur widely in deserts and arid rangelands. Eastern grey kangaroos
(M. giganteus) are a
more mesic species but have spread into the arid rangelands in
the past decades. Additional stock watering sites are suggested
to have facilitated this movement. We examined the impact of environment,
behaviour and diet on field water use by M.
rufus and M. giganteus at Fowlers Gap Arid Zone Research Station in western
NSW. The time was late summer and during the study the weather
was fine and clear, with mean daily maximum Ta being 31 °C (range,
29-33 °C) and mean daily minimum Ta being 18 °C (range, 14-21
°C).
M. giganteus had marginally higher water turnovers
(72 ml/kg.d against 58 ml/kg.d); however, they drank much more
frequently than M. rufus.
Differences between the species were also found in urine concentrations.
Patterns of behaviour and diet selection were also noted. Although
a specific reason could not be given for the higher water use
of eastern grey kangaroos, the provision of additional stock watering
sites likely facilitated their spread into the arid rangelands.
Publications
Blaney,
C.E., Dawson, T.J., McCarron, H.C.K., Buffenstein, R. and Krockenberger,
A.K. (2000) Water metabolism and renal function and structure
in eastern grey kangaroos (Macropus
giganteus): responses to water deprivation. Aust.
J. Zool. (in review)
Dawson,
T.J., Blaney, C.E., Munn, A.J., Krockenberger, A. and Maloney,
S.K. (2000). Thermoregulation by kangaroos from mesic and arid
habitats: influence of temperature on routes of heat loss in grey
kangaroos (Macropus giganteus) and red kangaroos (Macropus rufus). Physiol Zool.
(in press).
Return to index
Investigators: David Dunkerley
School of Geography and Environmental Science, Monash University,
Clayton, VIC 3168
During 1999, field experiments dealing
with the fate of rainwater in arid shrublands were continued.
Additionally, opportunistic observations were made of flow and
sediment transport in Homestead Creek and Fowlers Creek during
flood events. The fundamental goal of this work is to advance
the understanding of the hydrologic response of dryland landscapes
at a range of spatial scales. These range from the very local
scale of a single grass tussock or chenopod shrub, to the response
of mid-scale features like the patchy distributions of plants,
gibbers, and bare soil that is common in drylands, to the aggregated
response of whole river catchments.
The vegetation mosaics of the Fowlers
Gap and Broken Hill area were further explored using the cellular
automata modelling approach (Dunkerley 1999a). This work has suggested
that plant communities of this kind are relatively robust in the
face of the stresses imposed by drought and by the marked variability
of rainfall that occurs over parts of Australia strongly affected
by the El Niño - Southern Oscillation (ENSO) phenomena (Dunkerley
1999b). The hydrologic and erosional processes that arise in these
patchy landscapes have proven to be complex. The distributions
of vascular and microphytic plants are in the form of complex
mosaics. Additionally, however, there are associated variations
in the properties of soils, and of the surface across which any
runoff has to flow (Dunkerley and Brown 1999a). Furthermore, the
hydrologic response of these plant communities is further complicated
by the relatively little-known losses of water to canopy interception
on the leaves and stems of the plants (Dunkerley and Booth 1999).
One of the landscape features that
is unevenly distributed, and which is critical to the operation
of many hydrologic and erosional processes is plant litter. The
distribution of litter follows quite closely the distribution
of shrubs and grasses. However, litter particles float, and are
consequently easily swept through the landscape by even shallow
surface runoff, especially on bare surfaces. During movement,
plant litter often lodges against stems or on other obstacles
to form litter barriers. These small and ephemeral features are
nonetheless significant for the trapping of eroded soil, litter,
dung, and seeds that they induce. The distribution of litter in
turn influences the locations at which plant nutrients are returned
to the soil as the organic materials decompose. Laboratory experiments
using litter collected from Fowlers Gap have shown that one way
in which litter is dispersed from a point source such as a chenopod
shrub is by splash as raindrops, or water dripping from the plant
itself, strike the soil surface (Geddes and Dunkerley 1999). The
soil extending for some metres around such a plant receives the
distributed organic matter, and this contributes to the properties
of these soils, including an enhanced ability to take in rain
and surface runoff water, so increasing the availability of the
water in the plant root zone, as described in research mentioned
in last year's Annual Report.
Once water and sediment enter rills
and small gullies, they rapidly drain to local streams. Observations
made during and immediately after a small flood in Homestead Creek
have shown some unexpected results (Dunkerley and Brown 1999b).
In particular, it was found that the concentration of eroded soil
particles was greatest in the very first arriving flood water,
even after it had travelled many kilometres along the stream.
Indeed, both the concentration of soil particles and their size
declined in water following the flood front, in a very regular
way that was related to the logarithm of the time elapsed since
the flow-front had passed. Ordinarily, the highest sediment concentrations
are expected to be associated with the highest water flow rates,
which normally develop quite some time after the shallow flood
front has passed. Study of the Homestead Creek flood, and its
fate once it spilled into Fowlers Creek, suggested that the seepage
of water into the sandy bed (called transmission loss) is relatively
large in small flood events. It appears (but more work is needed
to confirm) that transmission losses may fall to a minimum for
floods that just fill the channel to the top of the banks, and
then increase once more for even larger floods that spill out
onto the surrounding landscape. If this is so, then it provides
a link to the importance of 'bankfull' flows that has been recognised
from humid zone streams for a long time.
Publications:
Dunkerley
D.L. 1999 (a). Cellular automata: the exploration of spatial phenomena
in ecology. pp.145-183 in A.H. Fielding (Ed.) Machine learning
methods for ecological applications. Boston: Kluwer Academic,
261pp.
Dunkerley
D.L. 1999 (b). Banded shrublands of arid western N.S.W.: responses
to interannual rainfall variability. Ecological Modelling 121: 127-138.
Dunkerley
D.L. & Brown K.J. 1999 (a). Banded vegetation near Broken Hill, Australia: significance
of soil surface roughness and soil physical properties. Catena 37: 75-88.
Dunkerley
D.L. & Brown K.J. 1999 (b). Flow behaviour, suspended sediment
transport and transmission losses in a small (sub bankfull) flow
event in an Australian desert stream. Hydrological Processes 13: 1577-1588.
Dunkerley
D.L. & Booth T.L. 1999. Plant canopy interception and its significance
in a banded landscape, arid western New South Wales, Australia. Water Resources Research 35(5): 1581-1586.
Geddes
N. & Dunkerley D.L. 1999. The influence of organic
litter on the erosive effects of raindrops and of gravity drops
released from desert shrubs. Catena 36: 303-313.
Investigators: Trish Fanning1 and Simon Holdaway2
1Graduate School of the Environment, Macquarie University,
Sydney
2Department of Anthropology, University of Auckland,
New Zealand
Support: Australian Research Council Large Grant
The Western
New South Wales Archaeological Program (WNSWAP) was initiated
in 1995 to investigate Aboriginal stone artefact scatters and
associated features, such as ovens, in a landscape context. The first four field seasons were spent at Mt Wood in Sturt
National Park, developing techniques based around the close integration
of archaeological and geomorphological data sets using electronic
survey technology and Geographic Information System (GIS) software.
This initial research established methods for accurately locating
and recording thousands of artefacts exposed by erosion across
tens of thousands of square meters of landsurface. Differential visibility and size sorting of artefacts was
controlled for through a combination of techniques: refitting,
analysis of artefact dimensions with slope and analysis of artefact
size with depositional environment. Having thus taken account of the post-discard history of
the artefacts, we have analysed their spatial distribution to
determine at what scale behaviourally meaningful clusters of artefacts
can be recognised. A
temporal framework for these investigations was provided by radiocarbon
dating of charcoal from the remains of ovens, and stratigraphic
analysis and dating of the alluvial valley fills.
At Fowlers
Gap, we are applying the results of this research to investigate
the Late Holocene archaeological record in one location with a
variety of landscape types as a way of assessing variation in
Aboriginal occupation intensity, mobility and resource use. Following reconnaissance in April, we chose for detailed
investigation, six land systems containing extensive lagged surfaces
with high artefact visibility. Pilot surveys in each of these, carried out in June, focussed
on assessing the variation in artefact density, degree of clustering
and the nature of assemblage composition between land systems. We will use this information to determine the sizes of
randomly selected sample sites within each land system which need
to be surveyed in the next two years. We have also located and assessed the condition of around
500 ovens, a sample of which we hope to excavate and date in the
next two years.
While our
project is still in its early stages, it is already clear that
stone artefacts are neither randomly nor uniformly distributed
across the landscape. Rather,
they are clustered in different ways in each of the land systems
investigated, reflecting the different ways in which Aboriginal
people interacted with the varied landscape in the past.
Investigator: A.G.
Fisher1, B.C.T.
Macdonald1, M.D.
Melville1, J. Chappell2 and D. Fink3
1School of Geography,
UNSW.
2Research
School of Earth Sciences, ANU.
3Australian
Nuclear Science and Technology Organization.
Gibson (1996) observed a shallow dipping Early
Cretaceous sediment, on the eastern edge of the Barrier Ranges
on Fowlers Gap Station. It has subsequently been termed the Telephone
Creek Formation. Iron and silica cemented pods and horizons of
ferricrete and silcrete were found to be dipping within this sediment.
The small discontinuous outcrops of silcrete and ferricrete have
a probable origin from groundwater discharge. The Telephone Creek
Formation is unconformably overlying the Devonian Nundooka Sandstone,
and is blanketed by the red clay sediments of the Bancannia Basin.
After correlation with the results of Baarda
(1968) on the Planet Bancannia South No. 1 bore, the Formation
appears to be a sequence (from youngest to oldest) of a finely
laminated micaceous shale, through to a micaceous sandy conglomerate
to a, micaceous grey shale. Since its deposition in fluvial and
lacustrine conditions, the Formation has been deformed by down
warping of the Bancannia Basin, or by tectonics. A fault offsetting
the formation may exist in the area where Fowlers Creek cuts through
the Barrier Ranges. Gibson (1997, 1998a, 1998b) has investigated
the post-cretaceous tectonics.
Some high level beveled surfaces within the
Barrier Ranges appear to be the surface trace of the Devonian
- Cretaceous unconformity. Due to this surface, and extensive
remnant surface gravel from the Formation existing across both
sides of the Barrier Ranges, the Telephone Creek Formation seems
to have previously had a much larger distribution. Outcrops are
also present on the western side of the ranges, situated on Floods
Creek Station. Mesozoic, possibly Early Cretaceous plant fossils
were found in a ferricrete bed within this Floods Creek outcrop.
This suggests strongly that the mesas and their underlying sediments
are not part of the Tertiary duricrust, and brings into doubt
the naming by Neef et al. (1995) of many outcrops of Tertiary
sediments that exist in the area.
Ward et al. (1969) had previously identified
Tertiary silcretes on Fowlers Gap Station. These small outcrops
exist on the western side of the Station in Sandstone Paddock.
They appear to be extremely different to the silcretes found within
the Cretaceous sediments. A satisfactory explanation for the existence
of the two varieties of silcretes has not yet been found.
References
Baarda, F., D., 1968, Planet Bancannia South
No. 1 completion reportfor Planet Exploration Company Pty. Ltd.
Cundill Meyers & Associates Pty. Ltd. (unpublished)
Fisher, A.G., 1997, An investigation of silcrete,
ferricrete and the Telephone Creek Formation at Fowlers Gap Arid
Zone Research Station, Western New South Wales. Unpublished Honours
Thesis, School of Geography, University of NSW.
Gibson, D. L., 1996, Cretaceous sediments,
tectonics, and landscape development in the northern Barrier Ranges. In: Regolith '96, Second Australian Conference on Landscape
Evolution and Mineral Exploration, The State of the Regolith 20. Co-operative Research Centre for Lanscape Evolution
and Mineral Exploration, (CRC LEME), Perth/Canberra.
Gibson, D. L., 1997, Recent Tectonics and
landscape evolution in the Broken Hill region. AGSO Research
Newsletter 26, 17-20.
Gibson, D. L., 1998a, Regolith and its relationships
with landforms in the Broken Hill region, western NSW. In:
Eggleton, R. A. (ed.), The State of the Regolith, Proceedings
of the Second Australian Conference on Landscape Evolution and
Mineral exploration, Brisbane, Queensland, Australia 1996.
Geological Society of Australia Special Publication 20.
Gibson, D. L., 1998b, Post-Early Cretaceous
tectonism and landscape development in the northern Barrier Ranges,
Western NSW. Proceedings of the 14th Australian Geological
Convention, Townsville, 6-10 July.
Neef, G., Bottrill, R. S. and Ritchie, A.,
1995, Phanerozoic stratigraphy of the northern Barrier Ranges,
western New South Wales. Australian Journal of Earth Sciences,
v. 42, p. 557-570.
Ward, C. R., Wright-Smith, C. N. and Taylor,
N. F., 1969, Stratigraphy and Structure of the North-East Part
of the Barrier Ranges, New South Wales. Journal and Proceedings,
Royal Society of New South Wales, v. 102, p. 57-71.
Investigators: Elizabeth Magarey and David Croft , School
of Biological Science, UNSW
An Honours thesis from the research
was produced in 1999 under the title 'The effect sheep grazing
on lizard assemblages in the New South Wales arid zone' with the
following abstract.
This study investigated the effect
of sheep grazing on the diversity, composition and relative abundance
of lizard species, in two vegetation communities, in the New South
Wales and rangelands. Pitfall
trapping was used to estimate the relative abundance of species
in grazed areas, compared to areas that have remained free of
sheep for over forty years.
Over the three seasons sampled, only
one lizard species, Ctenotus schomburgkii, was identified
as significantly affected by sheep grazing, having a lower abundance
in grazed mulga woodland sites. There was no difference in species diversity or richness
between stocked and unstocked areas.
Multi-dimensional scaling and correspondence
analysis revealed that individual sites responded differently
to stocking, and that the effect on lizard species was intimately
dependent on these habitat changes. Only where grazing resulted in a decrease in the volume
of large perennial shrubs, and a change in floristic composition
of the canopy, did the lizard assemblage change in composition. Where the structure and floristic composition of the vegetation
remained similar across grazed and ungrazed sites, the common
lizard species were unaffected.
The distribution of specific floristic/edaphic
associations was the primary determinant of lizard assemblage
structure in this study. The high degree of habitat partitioning demonstrated here
no doubt contributes to maintenance of the high species diversity
that is characteristic in the New South Wales and zone.
Further research is planned in relation
to sheep-induced piospheres for comparison with ongoing research
in Sturt National Park.
Investigator: Adam Munn and Terence J. Dawson, School of Biological Science, UNSW, Sydney, NSW 2052
Juvenile
red kangaroos (Macropus rufus) have the highest mortality
rate of any population cohort during times of environmental stress.
Severe or prolonged drought for example determines recruitment
into adult populations. This project is designed to examine the
physiology of juvenile kangaroos at their most vulnerable ages:
permanent pouch exit (250 days old) and weaning (360 days old).
Using animals obtained from Fowlers Gap, work conducted at the
university of New South Wales Kensington campus indicates that
juvenile red kangaroos have basic energy and water requirements
far greater than expected for an animal of there size, and considerably
higher than those of adult red kangaroos. To examine the ecological
implications of this, a study of the digestive constraints and
maintenance requirements of juvenile kangaroos is currently under
way. Preliminary results show that the ability of juvenile kangaroos
to digest poor quality, high fibre feed is somewhat lower than
that of adults. Under drought conditions, when only poor quality
feed is available, the digestive limitations and high demands
of juveniles no doubt contribute to the high rates of juvenile
mortality observed. Further, information from this study and will
be used in developing and testing foraging models at Fowlers Gap.
Investigators: Jim
Tilley and Alf Wojcik, School of Civil and Environmental
Engineering, UNSW
In early February 1999, Jim Tilley
visited Fowlers Gap and re-open edfour of the old Water Engineering
rainfall recording sites on the Station. These sites, along with
the rest of the Water Engineering sites (11 Pluviometer and runoff
plot sites as well as 6 water storage recording sites) were all
closed in 1988-89. The old sites were all strip chart recorder
instruments and were labour intensive requiring two man-days per
week to service the network. The rainfall sites that were reopened
are at Sandstone West (the old Frieslich Mort site), Nelia III
plot site, Mating large plot site and the North Mandleman large
plot site. While it would be preferable to have a much denser
network of rainfall sites these ones were chosen to give a north/south,
east/west cross sectional representation of the Station as a starting
point.
The four instruments installed are
tipping bucket rain gauges complete with data loggers. These instruments
can be visited a few times a year to check on their operation
and retrieve data after events as required. The data loggers record
the exact time and date of every tip of the bucket of known quantity.
At present station staff remove the loggers and replace them with
units posted out from Kensington and return the used units to
Kensington to download and disseminate the data. The data is stored
in the School's large HYDSYS time series database and can be accessed
from there to forward to the station for on site records or to
others on campus as required. The data is available electronically
for insertion into spreadsheets etc. or as hard copy graphs etc.
directly from HYDSYS.
To date approximately 18 months of
data has been logged, much of which is available by contacting
Mr. Alf Wojcik, P.O. at the School of Civil and Environmental
Engineering, (02) 9385 5025, 0415 271 723, or a.wojcik@unsw.edu.au.
Future plans include submission of quotations, to the management
committee, for a complete compact weather station to be installed
at the site of the old homestead weather station. This would use
a data logger on site connected, if required, to a PC in the office
for instant read outs and/or alarm conditions. Technology has
moved a long way in the last decade or so such that the current
cost of a state of the art, simple to operate, weather station
is now only a fraction of the cost of the original weather station
installed in the early 1980's. Likewise telemetry is now another
real option to be investigated that would be capable of connecting
all the outlying sites to the same system.
