Biodiversity is the variety of all life forms on earth – the different plants, animals and micro-organisms and the ecosystems of which they are a part. Australia is home to between 600,000 and 700,000 species. Many are found nowhere else in the world with around 84 per cent of plants, 83 per cent of mammals, and 45 per cent of birds found only in Australia. Over the last two hundred years, many species have become extinct and many others are threatened.

The Department administers the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The EPBC Act provides a list of species and ecological communities that are threatened, provides conservation advice and recovery plans for them, has a register of critical habitat, recognises key threatening processes and provides threat abatement plans.

Invasive species pose major threats to the rangelands biodiversity, reducing overall species abundance and diversity. Invasive species include feral animals, weeds, insects (and other vertebrates), introduced marine pests as well as diseases, fungi and parasites. They compete with native plants and animals for food and shelter, can cause land degradation and loss of habitat, can transmit disease and can cause devastation to a species through predation. [See ferals]

Although fire is a natural part of the ecology of the Australian rangelands, large scale fires, with unnatural frequency and intensity can adversely affect biodiversity. [See fire]

Climate change is an emerging issue for biodiversity in the rangelands. This is particularly so for species with limited distribution (living in one location) or those limited dispersal, as they are not able to move away from habitats that are experiencing changing temperatures or rainfall patterns. Although the Earth has gone through episodes of climate change in the past, this is the first time such major changes can be attributed to human-induced causes. While it may not be clear exactly what damaging impacts climate change is having on biological assets and ecosystem processes, we must work together to understand and measure these impacts and determine appropriate management action. [See Climate Change & Carbon]