Mapping Vegetation Changes on Reedy Lake

Reedy Lake is listed as part of the Port Phillip Bay and Bellarine Peninsula Ramsar Site, providing valuable habitat to birds and threatened species like the Australasian Bittern.

Changes to the amount of water entering Reedy Lake from 1970 until 2016 altered the natural cycle of the wetland. Since then, a change in the management of water inflows has allowed Reedy Lake to begin a rebalancing process that will help the diversity of habitats thrive.

Water Technology, Lloyd Environmental and Care Environmental worked with the Corangamite CMA to answer this question of how do changing water levels impact the types of vegetation in wetlands.

Furthermore, this project set out to understand whether the Ramsar Limits of Acceptable Change (LAC) and the environmental watering objective are being met using Water Technology’s innovative satellite imagery and machine learning resources.

This was analyzed by determining if the ecological characteristics of the wetland and the range in vegetation types have been maintained through water regime management.

The project uncovered interesting findings based on the water regime, elevation, and salinity, and how different vegetation types thrive in different conditions.

Water Technology used multiple sources of Satellite imagery to provide a timelapse that shows how the vegetation in Reedy Lake has changed over time.

Key Outcomes

Typha is a weed that was increasing in abundcance throughout Reedy Lake before the watering regime changed. The weed prefers less saline soils, while draw downs in the wetland increase soil salinity, therefore reducing the amount of Typha in the system.

Water Technology's analysis showed Typha was increasing within the wetland before 2016. The extent of the weed has been reduced following the periodic drying years in 2016, 2017 and 2018 within the wetland at elevations influenced by the
range of water levels that can be controlled with the watering regime (being 0-0.8 mAHD).

Native sedges and rushes have expanded significantly around the wetland’s margins following the drying years in 2016, 2017 and 2018. These native plants provide valuable habitat for native animal species within Reedy Lake.

Being within the Ramsar Limits of Acceptable Change is an excellent indicator to show the watering regime is supporting Reedy Lake and, in turn, any migratory bird species.

This also means that the environmental watering objective for the wetland is being met, helping to support the diversity of plant and animal species that inhabit Reedy Lake.

Having a dynamic, changing system that allows for greater diversity is crucial to the ecological function of the wetland.

To view the full summary and the reports from Water Technology, click below.

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