In Australia, there are somewhere between 600,000 and 700,000 species of living thing. Many, like the kangaroo and platypus, are found nowhere else on Earth.

Ecosystems

To support this array of life, our planet is divided into a wide variety of ecological systems or ecosystems. There are many types of ecosystems, but broad examples include:

• Terrestrial(land) ecosystem
  • Boreal (forest) ecosystem
  • Groundwater-dependent ecosystems
  • Montane (mountain) ecosystem
  • Urban ecosystem
• Aquatic (water) ecosystem
  • Freshwater ecosystem
  • Lake ecosystem
  • Large marine (ocean) ecosystem
  • Marine (salt water) ecosystem
  • River ecosystem

Rarely is there a distinct separation between one ecosystem and another. However, increasing urbanisation and human activity such as roads, mines and the forestry industry means we see increasing examples of abrupt transitions in the landscape.

Interconnected lives

The word used to collectively describe all the living things within an ecosystem is ‘biodiversity’ (Bio – meaning life and diversity – meaning variety.)

Biodiversity includes plants, animals, humans, bacteria, and insects. The amount of biodiversity within an ecosystem can be a good indicator of the overall health of that environment. Although, some places on Earth naturally have higher amounts of biodiversity than others. These places are tropical or sub-tropical places that can sustain huge varieties of plant life.

Countries like Australia, China, Brazil, and Malaysia are considered ‘Mega Diverse” countries with high numbers of species found nowhere else on Earth.

Just as ecosystems are interconnected to one another, so too are the things within them. Every plant and animal has a role in sustaining the ecosystem in which it lives. Even the rocks and minerals present have a role.

Within an ecosystem, living creatures tend to fall into three distinct categories:

• Producers - Typically plants and algae who get their energy from photosynthesis (light from the sun). Producers provide food for plant eating consumers
• Consumers - Plants or animals that feed on producers. Consumers who only eat plants are called Primary consumers. Some consumers are called secondary consumers, these tend to be carnivores who feed on plant eating consumers
• Decomposers - animals, plants, fungi or bacteria that feed on dead organisms. Decomposers break down the minerals and nutrients in the dead organisms, these are recycled into food for producers.

Each of these living organisms form part of a food chain that, in turn, connects to other chains to make a food web where all things are interdependent on the others. Changes, such as deforestation, over-hunting or pollution impacting these webs can cause ecological imbalance or collapse.

Large natural disasters can also impact food chains. Bushfires, floods, and changes in global temperatures can disrupt whole ecosystems. While recovery does occur, some ecosystems can take decades or centuries to return to their pre-disaster state. Some ecosystems adapt and change but, sadly, some never fully recover.

Rocks and non-living things play a role in these ecosystems too. Rocky outcrops and boulders provide the perfect habitat for plants, moss, and fungi to grow on their craggy surfaces and within cracks and cervices. Rocks can be warmed by the sun which can allow plants to thrive in an otherwise hostile environment and give animals like reptiles a place to bask.

Rocks can also provide an opportunity for species to reach above the ground level and have access to more sun, air, and water. Rocks and fallen trees provide places for animals to live, in and under them, providing shelter from the weather and from predators.