Other information:
March, 1999
The CRC was established under the Commonwealth Government’s
Cooperative Research Centre Program in July 1993. The Cooperative
Research Centre for Freshwater Ecology provides ecological
understanding to improve inland waters by collaborative research,
education and resource management.
Contents
1. The Yarra River under the microscope
2. Director‘s report, Conflicts over water for NSW
3. Marshes, swamps and billabongs–bugs love ’em
4. Captive-rearing might save endangered corroboree frog
4. Future of CRC for Freshwater Ecology
6. Ecoregions being used to set standards for river health
The Yarra River under the microscope
A $1 million study, being
conducted by the Cooperative Research Centre for Freshwater Ecology and
Melbourne Water, will investigate the changes brought about by
urbanisation on one of Melbourne's most famous landmarks—the Yarra
River.
The Yarra River plays an
important role in the lives of more than 2.5 Melburnians. From its
source high up in the Yarra Ranges, it provides most of the city's
water supply and in the outer east, the Yarra River supports an
agricultural industry worth more than $135 million annually. In
metropolitan Melbourne, the Yarra has become the focal point for
recreational and tourism activity. Yet very little is known about what
makes this lowland river tick.
Project Leader, Dr Peter Breen,
said that while there had been no major problems with the Yarra,
increasing development in the catchment meant that it was important to
ensure a secure future for the river.
“European settlement has resulted in some very significant changes to the river and its catchment.“
Land use has changed dramatically
with about 18% of the catchment now urban, while 46% is agricultural
and 36% is used for water supply and timber production.
“Urbanisation and agricultural
development have increased runoff and the transport of sediment,
pollutants and nutrients into the river.
“By building dams and levees, we
have reduced the river's interaction with its floodplain—the source of
much of the river's carbon, or fuel, supplies.“
The study will focus on three of
the Yarra's five distinct segments: rural lowland (from Wesburn to the
upper end of Warrandyte Gorge), gorge (Warrandyte Gorge to Fitzsimons
Lane), and urban lowlands (from Fitzsimons Lane to Dights Falls). It
will examine and compare the impact of urbanisation on each of these
segments.
This will be done by looking at
different parts of the food web in each segment, starting with the
nutrients that are bound up in the river sediments. The field work will
also include water quality analyses and microbiological work.
Ecological functioning in the river will be assessed by measuring the
production and use of oxygen and carbon in both the water and sediments
of the river.
Macroinvertebrates, or bugs, will
also be sampled at 30 locations along the three study segments to
evaluate patterns in the ecological structure of the river. Dr Breen
said that macroinvertebrates, by their presence or absence, could tell
us quite a bit about conditions in particular locations. They are used
extensively by water managers throughout Australia as indicators of
stream health.
The study will examine the
relationship between the macroinvertebrate communities and local and
catchment scale environmental variables, and whether these
relationships are similar in the small tributary streams and main stem
of the Yarra.
To date, bottom-dwelling macroinvertebrates, as well as those living on snags, have been sampled over autumn and spring.
Dr Breen said that despite years
of de-snagging in the Yarra, there was still an abundance of large,
woody debris in the river and so plenty of habitat for log-dwelling
invertebrates.
“This is probably because the
streamside vegetation along much of the Yarra's lowland section is
quite intact”, he said. It means, however, that snags are likely to be
an important habitat for bugs in the river, and that future management
actions will need to protect this habitat.
“We've also noted from analyses
so far that there seems to be a link between increasing urban
development and decreasing abundance and diversity in the invertebrate
communities. However the impact appears to be variable and snag
communities appear to be less affected than benthic, or
bottom-dwelling, communities”.
Previous studies conducted by the
CRC for Freshwater Ecology on small streams in the Melbourne area have
indicated that urbanisation does have an impact on stream health.
“It is likely, however, that
these impacts will be less severe in larger waterways such as the Yarra
where such a high proportion of the total catchment is presently
outside the metropolitan area,“ Dr Breen said.
Melbourne Water’s General Manager
of Waterways and Drainage, Ross Young said that the study would lead to
a better understanding of the ecology of the Yarra River. This would
improve the management of this essential natural resource.
Mr Young said the project was an important new initiative in Melbourne Water’s program to improve local waterways.
For further information contact:
Dr Peter Breen
Phone: (03) 9905 4061
Email: peter.breen@sci.monash.edu.au
Conflicts over water for NSW
As the competition over water
hots up, there are more and more strident calls to ‘zap the cap’ and
move away from the reforms that New South Wales is painfully edging
towards.
It is of little surprise that
some irrigators would like to do away with water controls. Upstream
irrigators would receive a licence to print money at the expense of
downstream irrigators and the environment. The over-allocation of water
in NSW has already led to a reduced security of supply, and it should
be clear that this is not in the interests of irrigators.
From time to time the quality of the science underpinning the various reforms comes under attack.
Science is never complete, and we
will never have perfect understanding. However, I believe that the
science underpinning the NSW river flow objectives is good and
appropriate to the issues at hand. If irrigators can see flaws in the
science, then they should explain exactly what aspects are flawed so
that we can debate the issue.
As I see it, the science revolves around three major propositions:
Proposition 1.
NSW rivers are degraded
I doubt that there are many
disputes about this. The Federal State of the Environment Report and
the NSW State of Environment Report catalogue the problems. The NSW
Rivers Survey, conducted by the CRC for Freshwater Ecology and NSW
Fisheries, showed that our rivers have suffered major losses of native
fish. It also showed that carp infestations were greater in more
regulated streams. Added to this, the algal blooms in the Lower Murray
in 1991 caused major dislocation to rural communities and tourism, as
well as threatening human health.
In my view the community is well
aware of the mismanagement responsible for this degradation to our
rivers. Even Sydney residents are now aware that failed catchment
management can have huge economic, environmental and social costs on
the community.
Proposition 2.
Altered flow regimes are one of several important causes of degradation
We have inverted the natural flow
in many of our rivers. These rivers now run bank full in summer as they
deliver irrigation water, and are at low flow in winter as the storages
fill. The loss of small to medium floods is no doubt responsible for
the failure of native fish to recruit, and this is probably one of the
causes of the carp explosion, since the native fish do feed on young
carp.
In some NSW valleys the water is
grossly overcommitted, with not only serious environmental
consequences, but also leading to a loss of security of supply
to irrigators.
Proposition 3.
Restoring appropriate environmental flows will reduce degradation
Reducing one of the major
stresses, altered flows, will hopefully improve the health of our
rivers. We do know that treating symptoms without addressing causes
does not work; a fact that is amply demonstrated by our approach to
salinity.
There are of course other
stresses that must also be addressed, such as water regulators and
weirs that stop fish migration, and agricultural chemicals that kill
zooplankton and fish (probably leading to algal blooms). Dams with
inappropriate release structures have been shown to release cold water
that alters downstream temperatures for up to 300 km in NSW, with
significant impacts on fish. Fertilisers and inadequately treated
sewage effluent provide nutrients to promote algal blooms.
The CRC conducted a workshop in
December 1997 to enable a group of 40 scientists, including CRC
researchers and representatives from most states, to scrutinise the
science behind the reforms. The scientists involved with setting the
river flow objectives made presentations and were questioned at length
by the audience. At the end of the day it was agreed that the science
was appropriate and the work should proceed.
Peter Cullen
Director
Marshes, swamps and
billabongs—bugs love ‘em
Far from being boggy wastelands, Australia's temporary wetlands harbour a teeming diversity of life—in fact bugs love 'em!
Recent work by CRC for Freshwater
Ecology postgraduate student, Rhonda Butcher, has revealed the
importance of temporary wetlands as distinctive and highly diverse
aquatic habitats.
Based at Monash University, Ms
Butcher has been studying 16 wetlands of varying permanency in the
Western Wimmera region of Victoria. Looking particularly at the
macroinvertebrates, or bugs, she is comparing the diversity of
ephemeral systems to that of more permanent wetlands. She will also
investigate whether commonly used techniques for assessing biodiversity
are suitable for conserving invertebrates in temporary wetlands.
Methods for sampling invertebrates in both ephemeral and permanent
wetlands will also be evaluated.
Ms Butcher said that more
emphasis tended to be given to permanent, rather than temporary
wetlands in Australia because of the continent's lack of permanent
freshwater sources. However, Victoria had lost about 4000 temporary
wetlands, mostly through drainage, since European settlement while it
had gained some 1800 permanent systems as a result of the construction
of artificial ponds and storages.
"While our temporary wetlands are
certainly the most numerous type in Australia, they're also the most
threatened by human activities," she said.
"Australian landscapes are strewn
with pockets of temporary wetlands that are periodically filled by
floods or rain. These wetlands and the species they harbour are
peculiarly adapted to an ecosystem that is both wildly variable and
unpredictable.
"So our temporary wetlands are
actually far more diverse than our permanent systems because that's the
type of environment that suits plants and animals that are adapted to
extreme, not average, conditions."
Ms Butcher's study focuses on the
small, invertebrate fauna of these wetlands—since much of the diversity
of temporary wetlands lies in the bugs and microscopic animals that
make their home there.
Current methods for classifying
wetlands tended to exclude invertebrates in favour of approaches using
plants or birds, water regime or salinity, she said.
Four categories of freshwater
wetlands—two temporary and two permanent—have been identified by the
Department of Natural Resources and Environment in Victoria using water
regime, plant associations and salinity. The two temporary wetlands
categories are: freshwater meadows, which contain water for about four
months each year, and shallow freshwater marshes, which contain water
for six to eight months of the year. The permanent freshwater wetlands
categories include deep freshwater marshes, which often fluctuate in
levels but are usually less than a metre deep, and the permanent open
wetlands, or lakes, which usually contain water up to five metres in
depth all year round.
Ms Butcher's study was conducted
at four sites from each of the four freshwater wetland categories. Each
wetland was sampled for invertebrates at one, three
and five months from filling. Physical and chemical data was also gathered and waterfowl counted during each wetland visit.
"There are just enormous amounts
of animals in these wetlands, Ms Butcher said. "From just four of the
temporary wetlands, with only a few minutes sampling in each wetland, I
collected 220,000 animals (invertebrates).
"This in itself makes temporary
wetlands very important for biodiversity, because invertebrates are an
important food for fish, birds and other larger invertebrates.
“Furthermore, the suite of
animals found in each wetland are quite distinct and there are often
dramatic changes in the species found in a single wetland from one
field trip to the next. This indicates that timing is a very important
factor in any wetland study and that sampling programs need to be
linked to flooding events rather than staff availability. It seems
critical to sample when wetlands are at the same inundation stage,
rather than seasonally or on an ad hoc basis."
In addition to their role in conserving biodiversity, temporary wetlands are also
a source of clear, clean water.
In shallow temporary wetlands sunlight can usually penetrate their
depth, allowing a thriving plant life, which play an important role in
absorbing nutrient and pollutant runoff
from rural lands.
Ms Butcher said that the
information gathered from each of the four types of wetlands would be
compared to provide a better understanding of how water permanency
influenced aquatic communities.
Ms Butcher is supervised by CRCFE
members, Professor Sam Lake (Monash University, Department of
Biological Sciences) and Dr Richard Marchant (Museum of Victoria).
For more information contact
Rhonda Butcher on:
Phone: 03 9905 5643
Fax: 03 9905 5613
Email: rhonda.butcher@sci.monash.edu.au
Captive–rearing might save endangered corroboree frog
A captive-rearing and breeding
program is underway in a last ditch effort to save the
strikingly–coloured southern corroboree frog.
The program is being conducted by
researchers from the University of Canberra in cooperation with the NSW
National Parks and Wildlife Service and the Amphibian Research Centre
(ARC) in Melbourne.
Famous for its spectacular yellow
and black colouring, the southern corroboree frog (Pseudophyrne
corroboree), which is found only in the Snowy Mountains, has undergone
a dramatic, yet mysterious decline during the last decade. Its cousin,
the northern corroboree frog (Pseudophyrne pengilleyi), found in the
Brindabella and Fiery ranges, is also experiencing decline, although
not to the same extent.
CRCFE member, Dr Will Osborne and
a small team of postgraduate students from the University of Canberra,
are leading the charge to save this nationally endangered frog.
Dr Osborne said the population
augmentation program for the southern corroboree frog was aimed at
assessing whether a combination of captive breeding and field
management would be effective in reducing tadpole deaths in the field.
It would also determine whether
increasing the recruitment level through to metamorphosis could boost
the number of breeding adults in remnant frog populations.
The experimental work, now in its
second year, has involved collecting half of each clutch of eggs from
three Snowy Mountains' sites for captive-rearing at the Australian
Research Centre where conditions were set to mimic the field
environment.
Field enclosures were constructed
in natural breeding pools for the half clutches left in the field so
that their progress could be monitored and compared to the
laboratory-reared individuals.
Strict protocols were maintained
for both the field and laboratory work to prevent disease,
contamination and poor practice from confounding the results. The
captive-reared tadpoles were returned to the field in mid-spring, after
snowmelt, where they were released into enclosures within the same pool
from which they were taken some months earlier. Two batches were
released one month apart and housed in separate enclosures within the
same pool so that their progress could be independently assessed.
Masters student David Hunter said
that the results from the first year of work confirmed that
captive-breeding could be successful in increasing recruitment in the
southern corroboree frog.
"We found that overall the
tadpoles that had been reared in the laboratory were more likely to
survive," Mr Hunter said. "The high field mortality might be the result
of the particularly poor climatic conditions experienced during that
year—lack of rain during autumn and late snow. We really need to repeat
the experiment during climatically good years to verify our result. "In
more recent work Mr Hunter has found that by simply placing eggs
directly into the shallow pools the same reduction in over-winter
mortality could be achieved as that obtained by captive-rearing. It is
hoped that in the longer term, this will be a more cost-effective
option than captive-rearing.
While the survivorship of the
captive-reared tadpoles was relatively high, many died once released
into the field. The tadpoles released first, however, had a greater
chance of survival than those released later.
Mr Hunter added that the reasons
for the decline in corroboree frogs were still unknown, although it was
possible that there was a link between ultraviolet-B radiation at high
altitudes and declining frog species.
The NSW National Parks and
Wildlife Service (NPWS) has produced a Recovery Plan for the Southern
Corroboree Frog, written by Dr Will Osborne, in response to the work
that has been done to date.The work has been funded by the Endangered
Species Program of Environment Australia, the NSW NPWS, the University
of Canberra, the Amphibian Research Centre and a generous donation from
a member of the public, made in honour of Colleen McCarthy. The project
is an in-kind contribution to the CRC for Freshwater Ecology.
David Hunter can be contacted for further information by phone on 02 6201 2937 or email to: hunter@aerg.canberra.edu.au
Dr Will Osborne may be contacted on 02 6201 5377 or email to: osborne@aerg.canberra.edu.au
Future of CRC for Freshwater Ecology
The CRC for Freshwater Ecology,
along with some 45 other CRC applicants, has now been interviewed. The
Minister for Industry, Science and Resources, Senator Nick Minchin, is
expected to announce the 30 successful CRCs towards the end of March.
We have put together a good
proposal and are optimistic of our chances. If successful, we will open
a Northern Basin Laboratory at Goondiwindi to enable us to undertake
research into environmental allocations and the ecological effects of
pesticides on the summer rainfall streams of the North. We have new
partners with the QLD Department of Natural Resources (DNR), NSW
Department of Land and Water Conservation (DLWC) and Victorian Natural
Resources and Environment (NRE) all joining, along with Griffith
University. Sydney Water is also planning to become a full member and
will then join the CRCFE Board.
I hope that we will have the
opportunity to continue the work we have started. Our vision remains
the same—to improve the condition of our waters. We will continue to do
excellent science and we will continue to strive to get the results to
the people who may be able to use the emerging knowledge.
Peter Cullen
Ecoregions being used to
set standards for river health
Setting obtainable ecological
objectives for streams is likely to be made easier by a new
classification system being developed by CRCFE scientists from the
Environment Protection Authority (EPA) in Victoria.
The new system, which classifies
Victorian streams into one of five regions, is based on topographical,
climatic, terrestrial vegetation as well as aquatic invertebrate
features. It aims to provide natural resource managers with the ability
to set ecological targets for the streams they manage based on these
'ecoregions'.
The project follows on from work
already conducted by EPA Victoria under an ANZECC grant, the CRCFE, and
the National River Health Program.
Project leaders Leon Metzeling
and Peter Newall said that in the past 'ecoregions' had been based on
land and climate features, such as soil types, topography and rainfall
and didn't really take into account what actually lived in the water.
The new classification system
relies on macroinvertebrates or bugs—grouped according to similar
assemblages of animals—thereby maximising the uniformity of the
ecoregions.
“We decided to let the bugs do
the talking” said Mr Metzeling. "These group boundaries are then
refined according to topographic and climatic characteristics."
The project draws upon the huge
macroinvertebrate dataset that has been assembled by the Monitoring
River Health Initiative (MRHI) under the National River Health Program,
which was set up by the Federal Government to assess the condition of
streams throughout Australia. More than 200 reference sites, or sites
assessed as being examples of what to aim for in terms of stream
condition, were sampled throughout Victoria to assemble this dataset.
Stream edge and riffle habitats
from the MRHI samples were identified to species level, and then
combined in the analysis to come up with site groupings that defined
regional boundaries. This information was related to a few
environmental variables to come up with a map of proposed ecoregions.
These regions were examined and
fine tuned by a workshop that included Victorian scientists and agency
staff who have expertise in macroinvertebrate ecology and distribution.
The project will develop a
geographic framework within which streams of similar types can be
assessed. This approach has been compared to other regional
classification systems, such as the Interim Biogeographic
Regionalisation for Australia (IBRA) , set up by the Australian Nature
Conservation Agency in 1995 for the purpose of terrestrial ecosystem
management.
To date five distinct
'ecoregions' have been identified. Region 1 includes the alpine areas
of the State while Region 2 is an assemblage of areas including some of
the mountainous and wetter areas of Victoria as well as East Gippsland,
the Grampians and the foothills and mountains of the Great Dividing
Range. Region 3 takes in other areas of the foothills of the Great
Divide where lower rainfall may be differentiating this area from
Region 2. Region 4 includes the lowland coastal streams mainly in the
eastern part of Victoria as well as central parts of the State. Region
5 covers most of the western half of the State and extends to the
riverine plains of the River Murray, including the lower reaches
of streams such as the Campaspe, Goulburn and Ovens rivers.
Mr Metzeling said that because
the classification system was based on reference sites, or examples of
desired stream health that had been sampled for the MRHI, the Melbourne
metropolitan area had been excluded as its urban streams did not meet
the reference site criteria.
He said that the project was
prompted in part by a concern that too many of Victoria's sites were
being assessed as equivalent to reference condition under the National
River Health Program's statewide AUSRIVAS models, or having attained a
satisfactory level of stream health.
"Clearly, this was not the case for many sites," he added. "It was too
easy to be assessed as a
reference site, so we felt that the benchmark under that protocol was
too low. Because this new approach is based
on geographic as well as
invertebrate homogeneity, it gets rid of a lot of variation. We hope it
will improve the resolution or sensitivity offered by the AUSRIVAS
models.”
"The approach we're using is
relevant to all states and territories in Australia and we believe that
the concept could even be exported internationally" Dr Newall said.
The work also demonstrates the
usefulness of a large dataset, such as that provided by the National
River Health Program's Monitoring River Health Initiative.
For further information contact:
EPA Victoria
Catchment and Marine Studies
Leon Metzeling
Phone: 03 9628 5955
email: leon.metzeling@epa.vic.gov.au
or Dr Peter Newall
Phone: 03 9628 5957
peter.newall@epa.vic.gov.au
A note from the Director...
Karen Markwort has resigned from the CRC for Freshwater Ecology to take up a position with the Australian Greenhouse Office.
Karen has done a fabulous job for
the CRCFE. We are probably the best-recognised CRC, and the quality of
our publications continues to attract positive comment from many
sources. When we started the CRCFE, there was some scepticism about us
investing in a Communication Manager, but this attitude quickly turned
around as Karen showed us how her skills and professionalism have added
value to our work as well as having an impact with our target audiences.
We wish her well as she moves from the liquid to gaseous phase of the water cycle.
Peter Cullen
Director
CONTACTS
Director:
Prof Peter Cullen
University of Canberra
PO Box 1
BELCONNEN ACT 2616
Phone: (06) 201 5168
Fax: (06) 201 5038
Email:
cullen@lake.canberra.edu.au
Dr Terry Hillman
Deputy Director/ Program Leader
Floodplain and Wetland Ecology
Murray-Darling Freshwater
Research Centre
PO Box 921
ALBURY NSW 2640
Ph: 060 58 2312
Fax: 060 431 626
Email:
terryh@mdfrc.canberra.edu.au
Professor Barry Hart
Deputy Director/Program Leader
Water Quality and
Ecological Assessment
Water Studies Centre
Monash University
PO Box 197
CAULFIELD EAST VIC 3145
Ph: 03 9903 2326
Fax: 03 9571 3646
Email: barry.hart@sci.monash.edu.au
Articles in Watershed may be reproduced without prior
permission provided the article is reproduced in full and the source is
acknowledged.
Editor:
Communication Manager
CRC for Freshwater Ecology
University of Canberra
PO Box 1
BELCONNEN ACT 2616
Email: karenm@lake.canberra.edu.au
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