The city of Melbourne, Australia is home to about 14 species of frogs, depending on where you draw the boundaries. And the boundaries of Melbourne are spreading outwards at a cracking pace, with new suburbs being built on its western, northern and south-eastern edges. Melbourne is already one of the most sprawling cities in the world, which means it covers a large area of land. At the moment, it measures about 60 km (37 miles) from east to west, and some suburbs are more than 40 km (25 miles) from the centre of the city.
The growling grass frog is the only species of frog around Melbourne to be on the national list of threatened species. It is listed as Vulnerable to Extinction under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). Growling grass frogs used to be common across Victoria, but their geographic range (the area of land where they might be found) has been shrinking. Melbourne is an important place for this species, but there are fewer and fewer wetlands around the city where these frogs still live. Research by Dr Geoff Heard and friends has found a big drop in the number of growling grass frog populations around the Merri Creek in northern Melbourne (a population is a group of animals or plants belonging to one species that live together in the same place).
Growling grass frogs are big frogs, with adults growing up to 10 cm long. They come in many shades of green to brown, and the male frogs have a fabulous growly call. You can click here to learn more about them and to listen to some calls. Claire Keely also has some great photos of growling grass frogs on her website. Claire is studying the population genetics of growling grass frogs in Melbourne for her PhD.
The growth of Melbourne is a big problem for the growling grass frog, because new suburbs are being built right where it lives. But with some careful planning, frogs and people should be able to live together. If the new suburbs have areas of parkland next to creeks, and new wetlands are built to help replace some of those that are covered over by houses and roads, this will help growling grass frogs – and other wildlife – to survive. Parks and wetlands will also make the new suburbs nicer places for people to live.
Property developers have complained about a draft plan to set aside areas of parkland along creeks (known as buffer zones) where houses cannot be built. Let’s hope that the Victorian government stands up for these beautiful and important animals in its updated plan to conserve animals and plants in the growth areas of Melbourne. This plan, called the Biodiversity Conservation Strategy, is due to be released soon.