UWA Changemaker - Dr Thomas Wernberg

ARC Future Fellow, UWA Oceans Institute, School of Plant Biology

Disappearing kelp forests

The Great Southern Reef is an interconnected system of temperate rocky reefs dominated by kelp forests. These kelp forests support a wealth of unique biodiversity, tourism, recreational and commercial fishing. The kelp forests dominate in cool waters and are threatened by warming, especially in combination with other stressors such as nutrient pollution and over-fishing.

Kelp forests have already been lost due to warming and other human pressures in NSW, Tasmania, South Australia and WA. We recently documented how a 2011 marine heatwave which affected the entire southwestern coastline caused a 100km range contraction of kelp forests in WA.

Not only did the kelp forests disappear but there was also a change in other seaweeds, fishes and invertebrates where temperate species declined and subtropical and tropical species increased. Heatwaves are on the increase due to climate change and the impacts to kelp forests in WA are a strong warning of what might be in store throughout temperate Australia and in kelp forests globally.

The lesser known reef

Our Great Southern Reef (GSR) gets very little attention compared to its well-known tropical counterpart, the Great Barrier Reef. I think it has to do with a couple of different things. First, it is right in the backyard of most people – 70% of all Australians live within 50 km of the GSR and therefore is not seen as exotic and is often taken for granted. More than 90% of all reef related media coverage concerns coral reefs even in states such as Tasmania, located many hundred kilometres from the nearest coral reef. 

The GSR water is often not as warm and clear as on many tropical reefs and therefore doesn’t always lend itself to stunning underwater filming. There is a perception that it is dull and boring, but this is not true. In fact, the GSR has the highest seaweed diversity in the world and it is a hotspot for temperate marine biodiversity where between 30-80% of species in different groups are endemic and found nowhere else on Earth. 

I also think most Australians are generally unaware of the value this system contributes to Australia. For example, Australia’s two most valuable single-species fisheries, abalone and rock lobster, are critically dependent on kelp forests. We have estimated that the GSR contributes ~$10 billion per year to GDP and, in some regions, accounts for ~15% of regional economies but this is a conservative estimate.  

Making a difference

I hope what we do will raise awareness of the value, importance and uniqueness of our kelp forests and temperate marine environments, and also of the pressure these ecosystems are under. When people are aware they also care and this is the first step towards mounting the capacity and political will to look after these ecosystems. The information we generate now will be important in documenting and mitigating any changes that might occur into the future. It all starts with knowledge and awareness.

My vision is to see the Great Southern Reef recognised as an entity, known to all Australians and beyond, appreciated and nurtured for its beauty, biodiversity and the contributions it makes to the Australian economy and national identity.

UWA and me

My time as a PhD student at UWA was life-changing in many ways. I gained some of my closest friends and many colleagues I still collaborate with. I never really left UWA in the sense that while I went interstate to broaden my skills and experience, I kept strong and active ties with UWA. I always planned to come back because of UWA’s strengths in marine science. I continue work on the unique marine environment in South-Western Australia. 

The mentoring I got at UWA from my PhD supervisor Gary Kendrick has been instrumental to my development as a person and a scientist. Over the years, I have also had a mentoring arrangement with former Pro Vice-Chancellor (Research) Alistair Robertson, starting way back when he was the Dean of Faculty of Natural and Agricultural Science. He mentored me throughout my career, even when I was no longer at UWA. His advice and guidance was decisive in building a research program and getting me through the hard years of competitive fellowships. I still turn to Gary and Alistair for advice and feel fortunate to have had these strong pillars to lean on. Of course, my initial UWA years were also important in seeding a research direction focused on kelp forests which I have continued since my PhD studies. 

About Thomas

Thomas was born and grew up on Bornholm, a small Danish island in the Baltic Sea. He completed a Master of Science in Environmental Biology and Geography at Roskilde University in Copenhagen. After getting an international scholarship from the Danish Research Council, he moved to Perth to pursue a PhD in marine botany at UWA. Following a short stint as an environmental consultant, Thomas took up a postdoc at the University of Adelaide. 

He moved back to Perth following an ARC grant and worked as a research fellow at Edith Cowan University for five years before starting as an AIMS-UWA research fellow in the UWA Oceans Institute. He is now an ARC Future Fellow at UWA’s Oceans Institute and School of Plant Biology.

His research provides understanding of how coastal habitats might respond to stressors such as climate change, invasive species and eutrophication. He is an Editor-in-Chief for the journal Aquatic Botany and an Associate Editor for the Journal of Phycology. More information on Thomas and his research can be found through his research lab website.