Mangrove Discoveries in FNQ

Exciting Botanical Discoveries in Chinaman’s Creek, Trinity Inlet while sorting out Cairns’ Mangrove Puzzle
By Hidetoshi (Mikey) Kudo

I am really excited about the discovery of two mangrove species: Bruguiera cylindrica and B. hainesii in Trinity Inlet. These discoveries were made in mid-January but it took three months for all the correct scientific processes to be finalised before announcing the news to the public. I have written a report about B. cylindrica for the North Queensland Naturalist Journal and have corresponded at length with people who study and protect mangroves. I have recently had a lot of media exposure and have finally had time to look back at these strange discoveries which are not really for me but for all of us. Those trees were just waiting for someone to find them!

I first found B. cylindrica, which is known to occur in India, South East Asia (including Taiwan) and PNG. Within Australia it was previously known to occur from Jardine River (Cape York) to Upper Endeavour River near Cooktown. This discovery confirmed the extension of its known range by 170 km. Some of the B. cylindrica I have found are well over 100 years old. I also found a dead cylindrica that had been decaying for many years. Around the dead tree there were a number of young to middle aged trees with flowers, demonstrating that regeneration is continuing in a healthy way.

Then I found B. hainesii, certainly the same genus as cylindrica. The discovery of B. hainesii is even more surprising. This species had only been considered to occur from southeast Asia to PNG. It had never been recorded in Australia and there were only around 200 known mature individuals left in the world. It is listed as Critically Endangered by the International Union for the Conservation of Nature (IUCN) and is on their Red List of Threatened Species. There are now 49 new mature individuals in Trinity Inlet to add to the world total which is an astonishing 20% increase in their numbers.

Some of the B. hainesii are very big with a diameter of 60cm and 18m tall. Dr Norman Duke, a well-known JCU mangrove scientist and the author of the book Australia’s Mangroves, visited Cairns in early March and confirmed both species. He estimated that the oldest hainesii is between 100 to 200 years old and this tree has a very well developed knee root system which is the best of its kind I have ever seen.

I was playing a puzzle game that I call ‘mangroving’ when I found these species The rules are simple – find as many mangrove species as possible in my neighbourhood. Soon after I started this puzzle many years ago, I realised that I could not find Red-flowered Black Mangrove anywhere in the Cairns CBD. After three years of searching, I asked my friend, local naturalist Brian Venables, where I might find them and he suggested Chinaman’s Creek. There is a new bike track there that goes over Moody’s Creek and Chinaman’s Creek. That is where these two species were found. I also found Red-flowered Black Mangrove there too.

These discoveries really prove that Cairns has a great diversity of mangroves. It made me realise that the answer is so simple. We have great rainforests surrounding Cairns and we have the Great Barrier Reef out there. The mangrove forests that link these two extraordinary ecosystems have to be great to keep everything healthy! I hope these discoveries can help people understand more about our environment. Last but not least, since the discoveries, I have met a number of people who have a passion for mangroves and work for conservation. My friend network has just exploded. This is definitely the greatest prize I have ever had from a puzzle game!

Mikey is a Cairns-based English/Japanese translator and dedicated citizen scientist