Community forum addresses biodiversity around the Avon River

By Hugh Rayner

On Saturday, March 15th, we held our Community Forum addressing the biodiversity around the Avon River. It was a great success with 60 attendees from Toodyay and surrounds hearing from four engaging speakers.

It was wonderful to have some younger people in the audience. There is hope for the future.

President Jenny White opened the forum with Acknowledgement of Country before Liz Kingston introduced the speakers.

The day began with the passionate Zenab Azam, Shire of Toodyay Environment and Sustainability Officer. Zenab outlined how biodiversity is under threat from human activity, particularly climate change. Zenab explained that there are seven species unique to Toodyay. Some are under threat. She discussed the problem of large numbers of dying eucalypts in the shire due to water shortage. She explained the shire Biodiversity Strategy is a small step to protecting the local biodiversity. She also offered a tip of using bi-carb and vinegar to kill rats without damaging the food chain.

The next speaker was the knowledgeable Greg Warburton. Greg shared that 40 kilometres of the Avon River flows through Toodyay, fed by six major tributaries. He discussed how early European settlers did not understand the nature of the river system, before the real damage came with the post war expansion of agriculture. The rapid clearing of some 92% of trees, including the use of tanks and chains, led to the soil being depleted. This led to heavy chemical use and the combined activities resulted in salinity.

The degradation continued with the River Training Scheme which completely changed the nature of the river and led to massive silting and erosion issues. Eucalyptus Rudis, like the magnificent specimen outside St Stephen’s (saved by early activism), went into serious decline in the catchment.  Foxes, feral pigs and cats caused massive mammal kills while feral fish like gambusia diminished the fish population. Greg’s speech was supported by a magnificent archive of photographs. He finished with some optimism about what can be done moving forward. This included tree planting and weed control activities with local environment groups and advocacy.

The next speaker was Max Howard from the Wheatbelt Avon Bird Group. Max gave an evidence-based assessment of the bird situation in the catchment using historical data since the 1940s. Max emphasised the importance of good data, pointing to a recent survey at Millard’s Pool where 102 species were observed, including 36 species of water birds. This represented a decline from the historic 47 species of water bird. The bigger concern is the decline in the number of birds, which has declined about 70% since the 1940s. This is largely due to declining food sources and changing weather patterns encouraging some birds to relocate to inland water sources. Max encouraged the need for regular surveys of the number of species and total bird numbers.

The final speaker was John Crook from the River Conservation Society (York). John gave a fascinating account of a York project investigating the status of the rakali, Australia’s largest rodent. The Rakali was almost hunted to extinction for its coat, but the aquatic mammal is now making a good recovery. Populations were discovered in seven of the twelve river pools in York. As an apex predator, eating gilgies, chicks, eggs and even turtles, they are a good indicator of river health. The risk factors for rakali are loss of habitat, especially logs in the river, poor water quality and unfenced sheep or stock access.

This article was published in the April 2025 edition of the Toodyay Herald, p. 33.