Cold-Blooded and In Trouble – Part 2

Our look into the endangered ectotherms of Victoria continues with a look into some of our swamp-loving species; A gorgeous lizard who hates his neighbours, and a very small, very pretty fish with a short lifespan and no scales!

Swamp Skink (Lissolepis coventryi)
Photo – Nick Gale

Victoria has 87 species of lizard, 52 of which are skinks, but unfortunately not all of them are as common as the ones you might find running around in your backyard in the warmer months! The Swamp Skink is a greenish-coloured, highly pattern medium-sized skink found in the coastal regions of Victoria. Considered ‘Vulnerable’ in Victoria, it is restricted to the densely vegetated swamps, heaths and sedgelands of coastal Victoria. It lives in a burrow, and has a home range that extends about 10m around said burrow which is aggressively defended against other Swamp Skinks – they do not get along with each other very well at all!

Swamp Skink numbers are currently in decline which is likely to lead to their extinction if action is not taken. Even though most (if not all) of the Victorian coastline is considered it’s ‘range’, it is only known from 72 sites within Victoria. Unfortunately, it is only considered to be ‘secure’ at 12 of these, 8 of which are in East Gippsland. It is actually presumed extinct at 5 or 6 of these, and another whopping 38 sites now have such a small amount of suitable habitat that their time has all but run out. The other sites are considered ‘uncertain’, which actually shows one of the key issues the species is facing; researchers don’t actually have a very clear idea of what their numbers are like. Ongoing research and surveying is crucial. Also, as is commonly the case, habitat loss is a huge factor. Suitable habitat has been either lost, degraded or broken up into small patches that aren’t connected and so the lizards become isolated (commonly referred to as habitat fragmentation), and this makes it even harder for the poor guys! A species with a long road ahead of it, and they need our help!

Eastern Dwarf Galaxias (Galaxiella pusilla)
Photo – http://fishesofaustralia.net.au/home/species/3393

When you think of endangered species, you mind probably doesn’t jump to small, stripy fish! The Eastern Dwarf Galaxias (Galaxiella pusilla) is a tiny fish, only reaching 40-50mm long, and it doesn’t have any scales! They like to live in lowland, shallow swamps with lots of aquatic vegetation, and like to dart into yabby burrows when threatened. They also complete their entire life cycle within a single year, meaning at some points in time they seemingly vanish from a waterway, then reappear once the young have grown up a little!

It’s thought that once upon a time the species was far more widespread and common, but wetland drainages have fragmented their habitat rather severely. Being so small and living in such hard-to-reach waterways makes them very difficult to survey as well. Much like the skinks mentioned previously, this species’ numbers are not very well understood. Also, they face a lot of competition from introduced species. The Mosquito Fish (Gambusia holbrooki) hunts the same food – small aquatic invertebrates such as mosquito larvae, and breeds in plague proportions very quickly, outcompeting the Dwarf Galaxias. Also, Brown and Rainbow Trout, as well as Redfin, eat the Dwarf Galaxias and can have negative impacts on their habitat as well. Stocking waterways with trout may seem like a great idea for fisherman, but the impacts on our native species can be catastrophic! This little fish may not be the most well-known fish in our waterways, but if we don’t help to spread the word about its plight it may quietly slip away.