In this eighth installment of the human stories behind herpetological research, we hear from Tim Cutajar. Tim describes the exciting rediscovery of the Booroolong Frog (Litoria booroolongensis), which was recently published in Herpetological Review. The citation for that publication is as follows:
Rowley, J.J.L. and T.P. Cutajar. 2018. Rediscovery of the Booroolong Frog, Litoria booroolongensis, on the Australian New England Tablelands after More than 40 Years. Herpetological Review 49(4):620–621.
In late 2014, my boss and now research supervisor Dr Jodi Rowley gave me a copy of Robin Moore’s In Search of Lost Frogs: The Quest to Find the World’s Rarest Amphibians. As I was rifling through the book’s pages, it wasn’t hard to imagine myself being part of those devout teams of scientists, traversing remote forests, rivers, mountains, and lakes all over the world to try to find amphibians that have been ‘lost’ for many decades. Needless to say that when about a year later Jodi told me we were going on our own ‘lost’ frog quest’ I was ecstatic!
With the help of a grant from the New South Wales (NSW) Government’s Environmental Trust “Saving Our Species” program, we planned a three-year mission in the rugged, rocky valleys of the New England Tablelands in the state’s northeast. One of Australia’s own ‘lost frogs’, the Peppered Tree Frog (Litoria piperata), hadn’t been seen since the early ‘70s. Our job was to determine if it was still out there, and, if it was, assess its conservation needs to ensure its survival. We hoped it might also give us a chance to find some of the other frogs missing from the region, like the Tusked Frog (Adelotus brevis), Yellow-spotted Tree Frog (Litoria castanea), and the Booroolong Frog (Litoria booroolongensis).
Among what awaited us in these three years were a foot-width precipice with the rock face on the side – a would-be support – entirely covered with well-guarded wasp nests, as well as a thousand meter descent into a canyon that we’d been told previously is inhabited by a ghost that on some nights can be seen feeding his chickens (we still really want to know if the chickens are ghosts also!). On one night we surveyed several kilometers up a small stream running through a narrow canyon. It wasn’t until we were on our way back that we realised upland rains had caused the stream to flood. After some deliberation and double bagging all the gadgets, we made our way back, a fair bit wetter than we’d planned. But we were also privileged to see an amazing diversity of the country’s frogs.
For me, the site with the ghost was a standout. Here we saw and heard more frogs than I ever had before in a single place. We had to watch every step because the river rocks were littered with the lemon-yellow males of the Stony Creek Frog (Litoria wilcoxii) in full breeding colour. Every 50 meters there was a new, near deafening chorus of Red Eyed Tree Frogs (Litoria chloris), Bleating Tree Frogs (Litoria dentata) and Broad-Palmed Rocket Frog (Litoria latopalmata) among others. It was also here that we saw the largest, probably oldest Green Tree Frogs (Litoria caerulea) we’d ever encountered in the wild. Over the course of these three years we were also given the opportunity to observe some threatened frog species in good numbers, like the Stuttering Frog (Mixophyes balbus), and were both introduced to the gorgeous but also threatened New England Tree Frog (Litoria subglandulosa). However, despite well over 200 person hours surveying about 50 km of rugged streams, plus much more of hiking and some serious four-wheel driving to the remote sites, the Peppered Tree Frog eluded us.
I couldn’t count the number of conversations Jodi and I had about why we hadn’t found it. The consensus is that the amphibian chytrid fungus that has caused frog extinctions worldwide is the most probable cause of the once common species’ decimation. It certainly fits the pattern; most the of region’s ‘lost’ frogs all disappeared around the same time – a common trend the chytrid fungus has been well-studied.
Exhausted and in pain from the 1000 m climb back out of Ghost Gully in less-than-ideal gumboots, and maybe slightly dejected by the fruitlessness of our efforts, we decided to take it easy the next night. I think it’s safe to say that most herpetologists positively correlate the likelihood of finding what you want with how much the search physically hurts you, so ambling up this flat, in no conceivable way lethal section of stream, Jodi and I resigned ourselves to the low-hanging fruit of recording calls of the Tablelands’ more ubiquitous species.
We did that for a while, then walked along a quieter stretch. As we wandered upstream, just following the light from our own head torches, we suddenly noticed a few pairs of eyes shining back at us from a patch of semi submerged rocks. At first we thought they might be moths; they have nearly the same rosy-coloured eye shine as frogs, and it was so quiet over there. But no, getting closer, definitely frogs. We couldn’t tell which at first. I had never actually seen Booroolong Frogs (Litoria booroolongensis) in the flesh, but when we arrived, there they unmistakably were on the narrow wet zone of protruding rocks.
The Booroolong Frog is, in its own right, a lost frog. Once one of the commonest species on the New England Tablelands, it seemingly disappeared from the region more than 40 years ago. It was thought to persist in only a few disjunct populations in the south of its historic range. Our rediscovery hugely extends the Booroolong Frog’s range, with the only other remaining populations in the northern half of its historic distribution being over 130 km further south.
Great things can be found in completely unexpected places – even lost frogs. Rediscovering the Booroolong Frog on the New England Tablelands is a huge step forward in its conservation. It also gives us hope that we can still rediscover some of Australia’s other lost frogs!