A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. A population is all the organisms that both belong to the same species and live in the same geographical area. Many of our species are found nowhere else in the world; we call these species 'endemic'.
Threatened species are those plant and animal species considered to be at risk of extinction in the wild.
There are different scales for how a species may be considered threatened:
- on a global scale
- on a national scale
- on a state scale
- on a regional and local scale.
In South Australia, threatened species are given formal legal recognition under the National Parks and Wildlife Act 1972 as Endangered, Vulnerable or Rare.
Why are species threatened?
Native plant and animal species and their populations are exposed to all kinds of threats that vary between species and populations. Common threats include:
- loss, as well as fragmentation and degradation, of habitat
- changed fire patterns (changed frequency, intensity and scale of fire)
- changed quantities and patterns in water and water flows
- competition with introduced plants (eg weeds) or feral/exotic animals for resources (eg food, light, water, shelter)
- predation by introduced animals (eg foxes and feral cats)
- grazing by feral animals (eg rabbits) and livestock)
- pollution and diseases (such as the root rot Phytophthora, an infectious soil and waterborne mould that causes plant dieback)
- illegal collecting, hunting and fishing
- climate change.
Effective management of these threats is vital to help threatened species survive into the future.