Biology Worksheet 2012 final - Home - Riverina ... · Web viewLimestone caves areas are known...

Ecosystems at riskLimestone Caves

Fieldwork at Yarrangobilly Caves

Map of Yarrangobilly Caves Map of Australia’s Limestone Caves

Page | 1Ecosystems 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.

Spatial Patterns and DimensionsPage | 2

Ecosystems at Risk: Caves Study Riverina Environmental Education Centre

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



Using geographical tools and skills collect data for

* Air Temperature *Relative Humidity *Light *Soil pH ( at the entrance only)

Characteristic Instrument & Unit

Entrance Twilight Dark

Air temperature Thermometer 0C

Relative humidity Hygrometer %RH

Light Meter lux

Slightly darker at night than daytime Total Darkness0 Lux

Never varies

Soil pH Universal indicator

Strongly Alkaline

(gained from historical testing)

Strongly Alkaline

(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 areasNo natural plants

*Mildew also

Plant height & % cover

Quadrat As for surrounding bushland- Mainly shrubs at entrance to 3m

100% coverage

5-10cm

50-70% coverage

NIL

NIL


Climate differences exhibited between the three ecosystems.



Diurnal change

The temperature varies as per the outside surrounds.

Significant daily and yearly changes.

Minor Nil

Seasonal change Minor Nil

Annual change Minor Nil

Air Temp change Minor Nil

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



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.


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).


Vegetation


Native Trees Mountain GumMountain Ash

Native Shrubs Grevillia, BursariaTea Tree, Hakea

Native Grasses PoaWallaby

Native Herbs Buttercup

Other Liverworts, Moss, AlgaeLichen (50-70% coverage)

Lampen Flora(near artificial lights)

Introduced Weeds St Johns WartScotch thistle

Introduced Trees ElmPine

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


Fauna


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


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


Human Impacts ( positive and negative) Traditional and Contemporary management practices

List of the Human Impacts in this ecosystemComplete 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


Human Impact Impact on the functioning of the ecosystem Management Practices Effectiveness of Management

Practices

Land clearing

Camp ground / Fire places

Toilets-sewerage into river

Washing in river-

Garbage dumping

Feral animals


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 Hydro-power 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.


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 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 actioneg. 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 equilibriumAssess 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

Ecosystems at Risk: Caves Study Lotus Diagram


1

Spatial Patterns

2

Weather & Climate

3Geomorphic and Hydrological processes

1.

Spatial Patterns

2

Weather & Climate

3Geomorphic and

Hydrological processes

4

Bio geographical processes

4

Bio geographical processes

ALPINE ECOSYSTEM AT

RISKYarrangobilly

Caves

5Adjustments in

response to natural stress

5Adjustments in response to natural stress

6. . Nature and rate of change which

affects ecosystem function

7Human impacts

Positive & negative

8Traditional and contemporary management practices

6. Nature and rate of change which affects ecosystem function

7Human impacts

Positive & negative

8Traditional and contemporary management practices


Biology Worksheet 2012 final - Home - Riverina ... · Web viewLimestone caves areas are known...

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