Australian Ecosystems Notes

Australian Ecosystems

Geological Formation & Evolution

  • The geological formation of Australia has significantly impacted the environment and the evolution of native species.

Environmental Effects

  • Droughts, floods, and bushfires have a substantial effect on Australian ecosystems.
  • These events are crucial for the life cycles of Australian native plants and animals.

Ecosystems in Australia

  • Australia contains 8 of the 14 worldwide ecosystems.
  • Ecosystems include deserts, tropical/subtropical regions, mediterranean woodlands, temperate forests/grasslands, montane lands, and tundra.
  • Australia's size allows for diverse vegetation and wildlife, isolated by mountain ranges.

Bushfires

  • Bushfires are destructive but a natural occurrence; some plants depend on them for germination.
  • Increasing due to changing weather patterns and extended droughts.
  • Caused by high temperatures and drought, providing dry fuel for fires.

Plant Adaptations to Droughts

  • Ephemeral plants: short life cycle, seeds dormant until rain.
  • Water storage ability: Stomata open at night to collect CO2CO_2 without water loss.
  • Small, narrow, grey/silver leaves; furry texture; water retention; fewer leaves.

Animal Adaptations to Droughts

  • Reproduction delayed.
  • Water collection structures: camel humps store fat that produces CO<em>2CO<em>2 and H</em>2OH</em>2O when digested.
  • Concentrated urine: Example: koalas.
  • Nocturnal behavior: large eyes, thermoreceptors.
  • Water collection from dew: Example: thorny devil.

Plant Adaptations to Fires

  • Thick bark: insulates and protects tissue.
  • Epicormic buds: regenerate branches after fire.
  • Lignotubers: grow new shoots after fire.

Populations

  • Populations and communities change over time based on births, deaths, immigration, and emigration.
  • Population Growth = (births+immigration)–(deaths+emigration)(births + immigration) – (deaths + emigration)