Working on wetland biodiversity takes one to some rather odd places. In my case, it has meant copious hours at the back of industrial estates, in flooded quarry pits and dodging unsavory types around urban backwaters. Hardly Kakadu or the Okavango Delta. But even my haunts are glamorous compared to some. Take the Western Treatment Plant – 11,000 ha of sewage treatment ponds in Melbourne’s south-west that processes half of cities’ effluent (a daily contribution from ~2 million people). I can assure that the WTP looks and smells just like you imagine; hardly the sought of place that should fire the imagination of wetland ecologists.
And yet it does, because the WTP is wetland of global significance. It even sports a RAMSAR listing to prove it. Twitchers are particularly smitten with the place, flocking on mass to see Brolgas, Bitterns, Red-necked Avocets, Freckled Ducks, Pink-eared Ducks and even the critically-endangered Orange-bellied Parrot. For herpetologists like me, the attraction is frogs. As well as being home to squillions of Melbourne’s more common frogs, the WTP supports arguably the single largest remnant population of Growling Grass Frogs in the country.
Our latest paper focuses on keeping the resident Growler population booming. A collaboration with Andrew Hamer of the Australian Research Centre for Urban Ecology, Ecology Australia P/L and Will Steele of Melbourne Water, the paper uses monitoring data collected by EA over four seasons to update an existing model of the metapopulation dynamics of Growlers in Melbourne, and uses this model to predict how managing the hydroperiod of key wetlands could bolster occupancy rates. Furthermore, it includes a test of this management action in the field, assessing the change in occupancy rate at ponds that received top-up watering in the final year of the study. Encouragingly, occupancy rate increased among these ponds relative to those that didn’t receive top-up watering, suggesting that managing hydroperiod could increase both the range and abundance of Growlers at the WTP.
I’ll sign off here and let you peruse the paper for the juicy details (fire me an email if you can’t get through the paywall). If you’re interested in frogs, wetlands, management experiments, simulations or Bayesian statistics, you should like this one.