A question of environment

Chad Buxton collecting rubble to examine for isopods.
Image: Gary Cranitch.


13 September 2010
Hundreds of thousands of tiny crustaceans called isopods live on tropical reefs, yet they have barely been studied in Australia at all. The CReefs Australia project is helping to change that picture.
Museum of Tropical Queensland researchers Chad Buxton and Dr Niel Bruce have been collecting isopods from the reefs directly around Lizard Island on CReefs expedition over the last three years, and they are still finding new cryptic species.
Scientists are beginning to understand the abundance and diversity of the species found here – but, Chad says, much work still needs to be done to describe the many new species and resolve their phylogeny and evolutionary history.
Different families of isopods can be found in deep ocean, in freshwater and on land, but Chad is focusing on isopods of the family Stenetriidae, which are free-living on coral reefs among other places.
"Stenetriidae haven't been particularly well-described in Australia, and no Stenetriidae species have been described on Australian coral reefs, so virtually all of the species that we find here are new to science," he says. "It is exciting work because you never know what you will discover next."
Chad estimates that through the CReefs project at least 30 new isopod species have been discovered in this family alone, and that there are many more to be described among other isopod taxa as laboratory work continues.
Chad has found some interesting patterns in the distribution of Stenetriidae directly around Lizard Island.
"Often, it's not a question of distance, it's a question of environment. I am currently examining micro-habitats, such as different beds of algae, different types of coral rubble, sand, and exposed outer-reef habitats to reveal patterns of species distribution," he says.
"I find different isopods on MacGillivray Reef – a sandy cay reef exposed to winds and currents, less than five kilometres from Lizard Island – than I find on the protected, inshore reefs around the island itself. I find different species in shallow areas than I find on the same reef at depths below 20 metres," Chad says.
"A more striking difference is found between the inner reefs and the outside of the barrier reefs. Basically, all reefs are not created equal to an isopod!"
Part of Chad's research will study the phylogeny of the Stenetriidae – the evolutional history and development of species over time – and the biogeography – the patterns of species distribution and abundance over geographical areas over time.
Chad is working on an Australian Biological Resources Study grant to study isopods at the Museum of Tropical Queensland in Townsville and is currently pursuing his PhD at James Cook University.