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Environmental importance

The Murray–Darling Basin is home to a huge range of species, including many that are rare and endangered, and some that can only be found in Australia. It also provides a seasonal habitat for birds that migrate from all over the world.

Wetlands support unique birdlife

There are over 30,000 wetlands in the Basin, and 16 of these have been internationally recognised for their importance to migratory birds. Some of these sites regularly support more than 20,000 waterbirds at a time.

There are diverse and threatened animals

Hundreds of different animal species live in the Basin, including:

  • over 50 fish species, including the iconic Murray cod
  • 350 bird species
  • 100 lizard species
  • 31 frog species
  • 46 snake species.

Many of these animals are only found in Australia. Some will only survive in the Basin’s unique environments that have evolved over thousands of years.

There are now over 95 threatened species in the Basin, including 35 birds and 16 mammals.

The Basin’s natural cycles and why they matter

All of these species, and the habitats in which they live, depend on the river for clean water and nutrients. Each environment has evolved to cope with the different weather events that can happen in the Australian climate, including drought, flood, heat and cold.

The amount of water flowing through the river system has always varied, with long droughts broken by large rainfall events and sometimes floods. In many areas, a certain amount of flooding is needed so floodplains receive water. Floodwater also washes nutrients into the river, giving a boost to the environment after a long drought.

These are the natural patterns of the Murray–Darling Basin. However, human activity and climate change can disturb these patterns. When this happens, the species that depend on the Basin’s rivers and floodplains for survival can be threatened. For example, when a wetland does not get enough water, it can interrupt the breeding cycles for fish or birds. This can reduce the number of animals in the area.

How the Basin environment has changed

Many First Nations are located within the Murray–Darling Basin. Aboriginal cultural heritage dates back over 45,000 years and the Traditional Owners and their Nations have a deep cultural, spiritual and environmental connection to the Basin’s lands and waters. Guided by traditional law and custom, Aboriginal people have long worked to protect and conserve Basin environments in their natural state, in order to maintain balance.

Europeans began arriving in the Basin in the early 19th century, and there have now been farms in the Murray–Darling Basin for more than 200 years. From the 1950s, human populations and industries grew quickly, and so did the amount of water taken from the river. This left less water for the environment.

As more water was used, the rivers in the Basin became less healthy, especially during droughts. Reduced river flow meant there was more salt in the Basin’s rivers, and more outbreaks of blue-green algae. When water levels dropped, acid sulfate soils were exposed and blackwater events happened more often.

There are fewer native fish, birds and mammals in the Basin than there were before Europeans arrived. At least 20 mammal species have become extinct and conservation is needed for about half of the Basin’s fish species.

These issues showed we had to change the way the Basin’s rivers were managed. Basin rivers need regular flows to move sediment, salt and nutrients through the system and out to sea. More water was needed to support important environments and to improve the health of the Basin for future generations.

In 2007, Parliament passed the Water Act, which put the Murray–Darling Basin Authority (MDBA) in charge of ensuring we have a healthier, working Basin that takes into account the needs of people and the environment. In consultation with many different stakeholders, the Basin Plan was developed to ensure water could be sustainably shared between all the people who use it and the the environment.

Climate change and the Basin

Climate change studies predict the climate in the southern Basin will become hotter and drier in the future, with more extreme droughts and less rain, but possibly also more extreme floods. All of this means water needs to be carefully managed so that it is always there for those who rely on it.

To manage water and protect the Basin, the Basin Plan takes the likely effects of climate change into account.

Updated: 24 Sep 2020