Ecosystems at risk
Limestone Caves
Map of Yarrangobilly Caves
Fieldwork at
Yarrangobilly
Caves
Map of Australia’s Limestone Caves
Page | 1
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
General Information
Limestone caves areas are known as “Karst” areas. The caves are a Karst system with about 320 known caves in varying stages of development and
differing levels of importance. This Karst is 12kms long and 1.6kms across. Each cave has its own ecosystem functioning and are managed accordingly.
The cave ecosystem is part of a larger catchment. The ecosystem within each cave is linked to the upper catchment by the flow of water. What happens
above the caves will have an effect on the caves themselves.
What is Karst?
Karst is the name given to limestone cave systems across the world.
They are unique ecosystems with some endemic flora and fauna (found nowhere else in the world)
Very little Karst can be found in Australia. The Nullabor plain is the largest Karst system in the Southern Hemisphere
Caves are a time capsule of past conditions. Studies of cave decorations have been used to determine past climate change
Why is this ecosystem at risk/fragile?

The cave system is very susceptible to change. Because it is so stable in terms of abiotoc factors (physical features- temperature, rainfall, humidity,
light) it cannot withstand change no matter how small. It is always, moist, dark and humid without diurnal (daily) or seasonal variations so everything
has evolved without the ability to cope with change

Each system is isolated, we say they are “islands in the sky” The nearest system is the Blue Waterholes. Caves system about 30kms away. So if
animals and plants cannot travel from one system to another

The caves are affected by the happenings in the surrounding area not just within the caves. For example the upper catchment Pine plantation had a
big effect on water flow and hence the caves environment

Organisms have become very specialised with reduced capacity to withstand change.
Page | 2
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Spatial Patterns and Dimensions
Using geographical tools and skills collect data for
Site
Altitude
Latitude
Longitude
Yarrangobilly Village Site/ Wild cave
35 39S
148 28E
North Glory Cave
35 43S
148 29E
Biophysical Interactions
Dynamics of weather and climate
Using the data in the graph above tabulate the monthly temperature data for Kiandra and inside the cave at Yarrangobilly.
Jan
Feb
Mar
Apr
May
June
July
Aug
Sep
Oct
Nov
Dec
Mean Daily
Temperature at
Kiandra
Mean Daily
Temperature
inside cave
Page | 3
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Biophysical Interactions
Using geographical tools and skills collect data for
* Air Temperature
*Relative Humidity *Light *Soil pH ( at the entrance only)
Characteristic
Instrument &
Unit
Air temperature
Thermometer
0
C
Relative humidity
Hygrometer
%RH
Light
Soil pH
Entrance
Twilight
Dark
Meter
lux
Slightly darker at night than daytime
Total Darkness
0 Lux
Never varies
Universal
indicator
Strongly Alkaline
Strongly Alkaline
(gained from historical testing)
(gained from historical testing)
Animals present
Evidence
Kangaroos, Wallabys, Lizards, Snakes,
Birds
Cockroaches, Spiders, Springtails, Cave
Cricket
Translucent spider, Blind beetle, Cave
cricket
Plant diversity
(number)
Quadrat
Larger diversity, and numbers
Moss, Lichen, Liverworts, Algae
Low diversity
Lampen Flora- artificially lit areas
No natural plants
*Mildew also
Plant height &
% cover
Quadrat
5-10cm
NIL
50-70% coverage
NIL
As for surrounding bushland- Mainly
shrubs at entrance to 3m
100% coverage
Page | 4
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Biophysical Interactions
Climate differences exhibited between the three ecosystems.
Entrance
Twilight
Dark
Diurnal change
Minor
Nil
Seasonal change
Minor
Nil
Minor
Nil
Minor
Nil
Annual change
The temperature varies as per the outside
surrounds.
Significant daily and yearly changes.
Air Temp change
Overview
Dark, damp & always humid. Further into the cave the more stable the climate
becomes
General rule is that the Temperature in a cave is the average yearly temperature of the surrounding area
Page | 5
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Biophysical Interactions
Geomorphic and hydrologic processes
Many landforms develop from the breaking down of rock (weathering), the removal of the weathered material (erosion) and the deposition of the eroded
material. Landforms include hills and valleys, floodplains, beaches, karst (limestone areas) and limestone caves.
Steps in Cave Development
1. Rain Water falls
2. Carbon dioxide from soil / air dissolves
3. Formation of acid groundwater
4. Limestone is dissolved by acid groundwater chemical weathering)
5. Caves develop
6. If water table drops the cave stops developing
7. Cave decorations (speleothems) begin to form. The deposition of calcite
begins the formation of stalactites and stalagmites.
Page | 6
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Nature and rate of change which affects ecosystem functioning
Describe the general landscape.
Karst system surrounded by granite mountainous wet forest
Explain how limestone caves form.
The area was under the ocean. Coral reefs formed.
About 300000 years ago there was uplift by tectonic forces.
As rainwater flows over the ground it combines with carbon from the plants forming a Carbonic acid which dissolves the limestone as it flows through small
cracks.
Over millions of years the cracks form into the caves.
Explain how speleothems (cave decorations) form.

Flow of water is the key.

Water drips off leaving a small ring deposit of calcite. Slowly this calcium builds up to lengthen the decoration.

As water drips onto the floor it leaves a buildup of calcite forming the stalactite decorations

Stalagmites grow from the floor up from the deposition of calcium carbonate from drops of water landing on the cave floor (below left).

Stalactites have formed along joint lines in the limestone where water has seeped through (below right).
Page | 7
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Vegetation
Entrance
Native Trees
Grevillia, Bursaria
Tea Tree, Hakea
Native Grasses
Poa
Wallaby
Introduced Trees
Liverworts, Moss, Algae
Lichen (50-70% coverage)
Lampen Flora
(near artificial lights)
Buttercup
Other
Introduced Weeds
Dark
Mountain Gum
Mountain Ash
Native Shrubs
Native Herbs
Twilight
St Johns Wart
Scotch thistle
Elm
Pine
Caves generally:

Plant Biomass is 0.2kg/m2 which is very low (Rainforest is 45kg/m2)

There is a lack of sun light for photosynthesis so only a few small, specialised plants survive hence only a small number and type of
herbivores can live in the ecosystem
Page | 8
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Fauna
Entrance
Twilight
Dark
Wallaby
Cave Cricket
Translucent Spider
Wombats
Cockroaches
Blind Beetle
Birds
Spiders
Cave Cricket
Lizards
Springtails
Snakes
Thylacine (Tasmania tiger) fossils indicate previous climatic conditions suited its habitation
Blind Harvestman Spider only found in the Harry Wood Cave- endemic very endangered

Fauna has unique physiological adaptations to survive in the dark, humid, moist cave environment: Long feelers, multiple long limbs
are an advantage. They have lost pigmentation, and have poor or no eyesight.

A behavioural adaptation is the Crickets move out to the entrance area to feed at night

Very specialised with reduced capacity to withstand change
Page | 9
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Human Impacts ( positive and negative)
Aboriginal history

Yarrangobilly means "Teeth water"

Groups travelled through the area on way to mountains for summer

Caves would have been used for shelter. Wet & damp not suitable for permanent accommodation. Rough terrain made living here difficult
European history

Late 1800s first Europeans came to the area and discovered the caves

Glory farm- cattle farm set up homestead on Yarrangobilly River

Introduced Poplar and Elm trees

Trout were introduced to the river from Adaminaby area

1920 cave house was constructed for tourism

1950s prison labour from Cooma was used to develop infrastructure for visitation

1967 NPWS took over management. Discouraged visitation because could not handle the sewerage an wastes- was destroying the system
Page | 10
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Human Impacts ( positive and negative)
Traditional and Contemporary management practices
List of the Human Impacts in this ecosystem
Complete the table by listing the inadvertent human effects on this ecosystem and the management practices employed (both traditional and contemporary)
Human Impact
Impact on the functioning of
the ecosystem
Management Practices
Effectiveness of Management
Practices
Highway Road
Old road construction
storage and dump site
Quarry- disused
Buildings, homestead,
sewerage
Pine tree plantation
Page | 11
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Human Impact
Impact on the functioning of
the ecosystem
Management Practices
Effectiveness of Management
Practices
Land clearing
Camp ground / Fire
places
Toilets-sewerage
river
into
Washing in river-
Garbage dumping
Feral animals
Page | 12
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Traditional and contemporary management practices
Upper Catchment Area
Maintaining the upper catchment area is very important in caves management. Any change in the water cycle will have an effect on the cave ecosystem. The cave
ecosystem relies on the water flowing in to the caves for much of the energy and food supply.
Reductions in the amount of water will affect cave development. Replacing native vegetation with pine plantations reduced the water entering the caves. Pines use 17%
more water than eucalypts.
Pollution has a big impact on water quality. Sources of pollution can be sediment from land clearing, animal faeces, sewerage, road dirt and oil, seepage from garbage tips.
Natural Sink holes were used as garbage tips in the past
How are the caves and catchment being managed on a sustainable basis?
The Yarrangobilly caves are managed by National Parks and Wildlife Service (NPWS) under the Kosciuszko National Park Management Plan.
Caves are categorised according to their importance and access is determined accordingly. At Yarrangobilly there are 6 categories of caves, varying from “open to public”
to “scientifically significant”. NPWS must manage both the caves and the catchment for the Yarrangobilly Karst system. 25% of revenue generated by tourism to the
caves is returned into cave care programs.
Water flow is critical to the caves so its management is extremely important. The general belief is that once you allow visitation you sacrifice the cave. However due to
historical visitation, there is an obligation to continue visitation into the caves. NPWS have included an education component with guided tours that play a critical role in the
ongoing management of this fragile and at risk ecosystem.
Pathing has been installed outside cave entrances to help reduce the amount of dirt entering the cave via the feet of visitors. Lighting systems are continually being replaced
with automatic energy efficient light system
NPWS staff must balance environmental and cultural heritage issues. For this reason they have retained the introduced Elms and Pines. NPWS produce their own Hydropower on site replacing old diesel generators that use to leak oil into river. A new sewerage system (costing $1.5 million) which uses no chemicals was recently installed and
it is located on granite site nearby- not on Karst. Local Poa grass uses up nutrients and provides a seed bank for regeneration works.
Feral Brumbies are kept away for the caves area with an active trapping and removal program in place.
Page | 13
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Cave Tour Notes:

Pure Limestone is milky or white

Limestone turns into marble when gets volcanic heat

Red colour is from iron picked up as water passes over rock with iron in it

Black colour is caused by bushfires. Some black staining from early visitors using kerosene lamps

Black bands caused by fires used to date age of cave

Moonmilk- bacteria reacts with limestone to form white growth

Water levels fluctuate

Calcite floats on water

Straws 6mm in diameter, hollow as water drips off leaves ring of calcite which is new growth. 98% turn into stalactites

Bacon water comes from side of cave and runs down wall

Bacon grows into Shawl and Shawl grows into Blanket

Helicitite turn up and around from roof

Column is Stalactite and Stalactite joined

392 Known caves

6 show caves with 5000 visitors per year
Jillabenan

is most decorated cave in Australia

2 million years old

Small cave with limited air flow.

Tour groups increase temperature and co2 which speeds up Lampenflora growth. When temperature increases the cave is closed
Jersey Cave

1.5 million years old
Glory Caves
Page | 14
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre

100000 years old
Least developed so self-guided tours in South Glory
Past Exam Questions & Examiner notes:
2013 HSC Geography
Question 25 – Ecosystems at Risk
“Assess the human impacts on the functioning of TWO ecosystems at risk”
General observations:

Almost all students named 2 ecosystems.

Many included spatial dimensions ( location, size, etc)

The majority of answers were quite detailed

Students seem to have found it easy to outline / describe human impacts on ecosystems and managed to include several for each ecosystem
Discriminators:
Human impacts: These are many and varied and directly relevant to the ecosystems chosen

Simplistic coverage of impacts – list human actions eg. Dirt access roads, accommodation & buildings, sewerage pollution, farming, forestry,

More comprehensive coverage of impacts;
human action  effects of action
eg. Tourism sacrifice of caves loss of ecosystem
Human impacts on the functioning

A lot of students didn’t address the term “functioning”

Requires a greater depth of knowledge / understanding

Explicitly talks about how the actions of humans impacts on the functioning of an ecosystem

Functioning = energy flows, nutrient cycle’s, chemical transfer, photosynthesis, food chains, food webs, trophic levels, linkages, biodiversity, interdependence,
stability, structure, biophysical interactions, seral progression, succession, dynamic equilibrium
Assess  Judgement

Simplistic judgement – a statement like “ this impacts on the functioning of the ecosystem” with no follow up given

Implied impact on the functioning of the ecosystem – not explicitly stated

More comprehensive – makes a judgment about the impact of one human action on the functioning of an ecosystem – but doesn’t carry it through all examples of
human impacts

Explicit, comprehensive judgement supported by evidence about the impact of human actions on the functioning of the ecosystem.

Impacts are: positive, negative, devastating, destructive, minimal, extensive, damaging, disturbing, constructive….
Caves Ecosystem at Risk: Lotus Diagram
Page | 15
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre
Ecosystems at Risk: Caves Study
Lotus Diagram
1
2
Spatial Patterns
Weather & Climate
4
Bio geographical
processes
1.
2
Spatial Patterns
Weather & Climate
3
4
Geomorphic and
Hydrological
processes
5
ALPINE
ECOSYSTEM AT
RISK
Yarrangobilly
Caves
Bio geographical
processes
6. . Nature and rate
of change which
affects ecosystem
function
6. Nature and rate
of change which
affects
ecosystem
function
3
Geomorphic and
Hydrological
processes
7
Human impacts
Positive & negative
Adjustments in
response to
natural stress
5
Adjustments in
response to
natural stress
8
Traditional
and
contemporary
management
practices
7
Human impacts
Positive & negative
8
Traditional and
contemporary
management
practices
Page | 16
Ecosystems at Risk: Caves Study
Riverina Environmental Education Centre