Kelp ecosystems dominate ca. 25% of the world’s rocky shores. These ecosystems are responding to human-induced climate change and climate variability all over the world; in most regions kelp forests are retreating due to ocean warming and human pressure, while in South Africa, uniquely, early evidence suggests that kelp ecosystems might be expanding, possibly due to cooling from increased upwelling.
Three species of kelps have their distribution limit in the southwestern Cape, with closely related overlapping populations with different ecological requirements. In addition, there is an overlap in the region between two different ecological states of kelp forests, with and without sea urchins and other major grazers.
Some of the questions addressed by the project include:
- What environmental and ecological factors best explain the distribution of these kelp species?
- What ecophysiological characteristics of the kelp species, life history stages, and forms interact with ecological and climatically-driven environmental variables to influence kelp distribution across the transition?
- How do the distributions of associated organisms change in response to kelp species change (or vice versa), kelp form variation, grazer prevalence?
- How might kelp distribution be projected to change in the future from global climate change scenarios?
- Do other species show evidence of change in distribution in line with kelp changes?
The project will contribute to a number of parallel projects which we are members of, including an Australia-South Africa study on genetics and climate change in Ecklonia radiata, the global KEEN project on kelps and climate change, a South Africa-wide collaboration measuring inshore seawater temperature regimes, and a project on molecular systematics of kelps.
Our group consists of Prof. John Bolton (the University of Cape Town), Prof. AJ Smit (the University of the Western Cape), Prof. Rob Anderson and Mark Rothman (Department of Agriculture, Forestry and Fisheries), Dr. Laura Blamey (the University of Cape Town) and Dr. Thomas Wernberg (the University of Western Australia).