In the lead up to our Annual Marine Science Forum on the 4th and 5th May, we will feature a post about each of the scientists presenting this year.

Dr. Scott Ling, Marine Ecologist, Institute for Marine & Antarctic Studies, University of Tasmania.

My research experience spans a broad range of marine ecological investigations with a strong focus on in situ sub-tidal surveys and experimental work which has spanned > 1500 research dives over the past 14 years.  Much of my work has centered on investigating the effects of human stressors on marine ecosystems such as fishing, climate change and the introduction of invasive species. Central to my interests is the identification of alternative ecosystem states and processes influencing phase shift to less desirable states, particularly those that prove difficult to reverse.

Presentation title: Ocean warming, overfishing and overgrazing of kelp beds in eastern Tasmania

Presentation outline:

Kelp beds appear resilient to a range of perturbations but can be pushed beyond critical thresholds leading to collapse, with recovery exceedingly difficult to achieve. In south-eastern Australia, coastal waters are warming at more than 4 times the average rate of global ocean warming, leading to major re-shuffling of marine species and major changes on rocky reef systems in this region. In eastern Tasmania, a most important range-shifter is the long-spined sea urchin (Centrostephanus rodgersii) which has extended its’ range south from NSW to Tasmania’s rich and productive kelp beds. This presentation details how this ecologically important sea urchin has responded to climate change and dually explores the multiple processes influencing catastrophic overgrazing of kelp beds by the sea urchin, as is now observable within eastern Tasmania. Continued warming predicted for this coastline will favour increased sea urchin survival, promoting ongoing population expansion and ultimately increased likelihood of populations reaching sufficient abundance to affect widespread overgrazing. Finally, this presentation shows how management of non-climatic local scale stressors, i.e. reducing impacts of fishing on sea urchin predators, can be used to increase resilience of kelp beds against overgrazing given the large scale climate-driven increases in the abundance of sea urchins.