19 Jan Another great example of “just add water” – Scale Swamp, near Dunkeld, SW Victoria
Scale Swamp is another great demonstration of the benefits of restoring hydrology to drained wetlands. This 100 hectare swamp to the south of Dunkeld has a long-term history of drainage for grazing and low-intensity cropping. In 2013, under the Commonwealth Government funded “Wetland Restoration on Private Land” project, Nature Glenelg Trust and Dunkeld Pastoral Company worked together to decommission a drain and install fencing around the restored high water mark. We’ve been watching and enjoying the changes over the past five years and have been amazed at the response in vegetation and birdlife. I headed into Scale Swamp between Christmas and New Year’s Eve to find there was still a significant amount of water. Unlike many of our other restoration sites, Scale Swamp is relatively shallow and more grassy than the deeper, freshwater marshes we have worked on. You can see a timeline of transition of the vegetation in the photo sequence below. In large parts there has been an almost entire replacement of exotic pasture grasses with the native Australian sweet grass (Glyceria australis) and also increased coverage by native sedges (Eleocharis acuta) and other aquatic herbs (Potamogeton, Myriophyllum and Ranunculus species). Despite previous research at the site (by Michelle Casanova) showing that a diminished native wetland plant seedbank persisted at the site, crucially the restored hydrological regime has given those wetland species that have held on, the vital competitive edge they had been waiting for.
The biggest surprise to me during my recent visit came while I was photographing the concentrations of water birds. I didn’t see them with the naked eye but while reviewing a photo I’d just taken, I noticed some brolga in the background of a shot. Turns out there were three. Given the isolation of this site, the restored hydrological period and ideal vegetation assemblage, I’m confident that Scale Swamp is now an ideal spot for brolga breeding.
Alongside the brolga were spoonbills of both species, a large number of black winged stilt, both species of herons, duck and teal, swans, whiskered tern, dotterels and a flock of sharp-tailed sandpipers darting across the swamp. Based on water levels, I would expect we’ll still be seeing this sort of activity through until the end of summer. We have done some aquatic surveys over the past years and can confirm that frog populations are also healthy but we are yet to hear growling grass frogs; however, based on the response so far, I get the feeling it is only a matter of time. If we can manage another good rainfall season in 2018 I’m hoping to organise a field day so more people can get to experience first hand how quickly a degraded wetland can spring back to life, just by adding water.