Unexpected ‘gems’ in the city – NGT documents wetlands of the Adelaide Park Lands

Back in March Ben, Bryan, Tessa, NGT intern Vicki Bruce and long term NGT volunteer Andy Lines were busy in the Adelaide Park Lands on a project commissioned by the City of Adelaide. The objective was to map the wetland vegetation and survey the mammals, reptiles and amphibians of the wetlands of the Park Lands. The project was part of a suite of investigations to document the ecological values of the Park Lands in 2024. Our project focused on three wetlands; Karrawirra Pari/the River Torrens, a wetland in Wirrarninthi/Park 23 (near West Terrace Cemetery) and a recently (2022) constructed wetland in Pakapakanthi/Victoria Park. The final report is now available on the NGT website.

Submerged aquatic vegetation in Karrawirra Pari, which we have been monitoring since 2020, had lower cover this year compared to previous years. The cause of this decline is difficult to determine with confidence but could include a decline in water quality, increased deposition of debris (e.g. leaf litter and plastic, noted during the survey) onto the lakebed, the physical removal of plant material during high flow events, increased grazing by waterfowl, increased disturbance by European Carp or any combination of these factors.

Away from Karrawirra Pari there are patches of wetland vegetation in surprisingly good condition for an urban area. The wetland near West Terrace Cemetery features some dense rush and sedgeland surrounded by riparian River Red Gums and is a hidden gem close to the city. The recently constructed wetland in Victoria Park has diverse, wetland vegetation in good condition with evidence of natural recruitment of planted species and the natural establishment of native aquatic species that were not planted (e.g. Potamogeton crispus). This wetland is fast becoming a cherished feature of the Park Lands with high visitation by local residents. It shows what can be achieved in the urban environment with clever design.

The fauna surveys documented 14 vertebrate species. Notably, a population of Spotted Marsh Frogs (Limnodynastes tasmaniensis) has established within the constructed wetland. There are also anecdotal reports of Common Eastern Froglets (Crinia signifera) and Eastern Banjo Frogs (Limnodynastes dumerilii) now calling from this wetland. Although we weren’t targeting birds, we caught the often heard but rarely seen Little Grassbird (Poodytes gramineus) in an Elliott trap in the constructed wetland. The bird list for this wetland is by all accounts constantly increasing and is an interesting study in how an ecosystem gradually builds from a blank slate to something more complex through time.

This project was commissioned by the City of Adelaide