Changing Landscapes – Biodiversity

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An Australian rabbiter making a living from pests

An Australian rabbiter making a living from pests
An Australian rabbiter making a living from pests

The release of rabbits into the Victorian bush in 1859 was an environmental disaster. The 24 animals multiplied to plague numbers that are still with us today. Rabbits affect biodiversity and cause soil erosion by tunnelling into the ground and nibbling plants to the roots.

Trapping provided food and income for many people until it was banned in NSW in 1980. Today it is considered more humane, efficient and effective to control rabbits by destroying burrows, building fences and using viruses such as myxoma and calici.

Questions

  1. What were the consequences of humans releasing rabbits in the Australian environment?
  2. What are some ways humans have tried to control rabbit populations?
  3. Why are rabbits more of a pest here than in Europe where they originated?
  4. List other introduced plant and animal species that have had a severe impact on the Australian environment.

Kosciuszko: the main divide

Kosciuszko the main divide
Kosciuszko the main divide

Snow used to fall reliably on the alps of the Great Dividing Range. It melted in spring to feed rivers flowing to both the east and west. The alpine climate suited many species of plants and animals that are now under stress as the climate warms.

In 2001 CSIRO scientists estimated that, due to the greenhouse effect, daily temperatures in south-eastern Australia could increase up to six degrees by 2070.

That spells doom, not only for snow-sport industries, but also for many of the plant and animal species that thrive only in cool temperatures.

Questions

  1. What are some other effects of global warming?
  2. List human activities that produce greenhouse gas emissions.
  3. What are some ways you can reduce the amount of greenhouse gas you produce in the home?
  4. Describe some animal and plant species that live in Australian alpine environments.

A blackbutt forest on the Comboyne Plateau

A blackbutt forest on the Comboyne Plateau
A blackbutt forest on the Comboyne Plateau

Before 1900 the Comboyne Plateau in northern NSW was covered with dense subtropical rainforest. European settlers cleared most of the trees to create grazing and dairy farms, so only a few pockets of remnant rainforest remain today.

The area lies between the Manning and Hastings River valleys, has deep rich basalt soils, and receives relatively high rainfall. These attributes make the Comboyne Plateau a valuable farming area.

Avocados, macadamias, blueberries and other fruits now stand where once the blackbutt trees grew.

Questions

  1. What kind of environment is shown in this photo?
  2. Which group of Indigenous people lived on the Comboyne Plateau? You can use the AIATSIS Aboriginal Australia map.
  3. How has this environment changed since 1900?
  4. How has the biodiversity been affected?

Cattle grazing near Mt Kosciuszko, a fragile environment

Cattle grazing near Mt Kosciuszko, a fragile environment
Cattle grazing near Mt Kosciuszko, a fragile environment

Farmers and drovers took sheep and cattle to graze in the high country every summer from 1830 to 1969.

Pastures were burned to produce fresh green growth. Animals selectively ate soft plants between tough tussock grasses, leaving large areas of soil exposed to wind and rain.

It caused soil erosion and habitat destruction.

In 1943 state governments introduced snow leases to restrict grazing seasons.

Kosciusco State Park (now Kosciuszko National Park) was established in 1944 and grazing stopped completely in 1969. The focus then turned to tourism and preservation of biodiversity.

Questions

  1. What animals would have been affected by habitat destruction?
  2. Why is soil erosion such an environmental problem?
  3. How would the Snowy Mountains Hydro-Electric Scheme have been affected by soil erosion in the mountains?
  4. Do you think horses should still be allowed in national parks? Why or why not?

Cattle coming to water

Cattle coming to water
Cattle coming to water

Cattle love to spend time in and around rivers but their hard hooves create compacted stock tracks and churn up soft soil. This makes river banks susceptible to erosion and increases sediment in the water.

The animals can also overgraze the area, leading to the loss of habitat and of local biodiversity. Their manure and urine increases phosphorus in the water, changing in-stream habitats.

Fencing river banks is very expensive but it is often the only way to protect the riverine environment.

Questions

  1. How have human activities impacted on the environment in this photo?
  2. Which native animals rely on the riverine environment?
  3. How would those animals be affected by fences?
  4. How did land settlement by European farmers affect the lifestyle of Indigenous people?

Lodore Falls, Blue Mountains National Park

The beauty of the Blue Mountains forests has attracted bushwalkers and tourists since the 1890s.

With other naturalists, Myles Dunphy explored, mapped and negotiated for 30 years to get the Blue Mountains National Park established in 1959. The Greater Blue Mountains Area was declared a World Heritage site in 2000.

Its sandstone plateaus have deep crevices, which have their own microclimates. During climatic changes in the past, animals and plants found refuge in these crevices when conditions in other areas became unsuitable.

Questions

  1. Is this a wet or dry environment?
  2. What animals would live here?
  3. Explain how climate change can affect an animal’s habitat.
  4. Indigenous people once lived in the area that is now National Park. Do you think people should be allowed to live in national parks? Why or why not?

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