Coral reef connectivity

Coral reefs have been and continue to be challenged by an ever increasing number of both global and anthropogenic influences. Sea surface temperatures have been and continue to be on the rise, and evidence points to a deepening of the stresses associated with climate change and an increase in the frequency, scale and mortality associated with coral bleaching (which is triggered by episodes of elevated sea temperatures) and mortality of coral reefs. While considerable information is available on the disturbances associated with human and climate driven temperature changes, we still only have a narrow understanding of how reef systems will respond to impacts of this scale. Differences in recruitment, the relative connectivity of reef systems and the life histories of corals have been shown to be crucial for determining patterns of recovery or decline in reef systems. Thus, reef connectivity is a critical element in understanding how reef systems will fair under increasing stresses such as that represented by climate change, and such connectivity estimates have been recently highlighted as one of the major future research avenues for coral reefs. It is anticipated that this type of information will improve our understanding of the relationship between disturbance and recovery.

Population genetics Population genetics offers a useful advance in understanding reef connectivity, as the relationship between the dispersive ability of organisms and the genetic differentiation of populations not only provides a fundamental link between ecology and evolution, but measures of genetic relatedness also represent a proxy to the extent of recruitment that is occurring between two areas. Despite the number of new molecular genetic tools that are available for population-level processes, coral population genetic studies seem to have lagged behind most other marine disciplines.

Thus, I am currently testing recently isolated genetic markers to assess population connectivity in scleractinian coral species along the East Australian coast. It is hoped to develop a technique that will easily be applicable to other coral species and other geographic locations.

Selected Publications:

Ridgway, T., Riginos, C., Davis, J. and Hoegh-Guldberg, O. (2007). Pocillopora verrucosa genetic connectivity patterns in Southern African Marine Protected Areas. Marine Ecology Progress Series. In press.

Ridgway, T. and Gates, R.D. (2006). Why are there so few genetic markers available for coral population analyses? Symbiosis. 41: 1-7.

Ridgway, T. (2005). Allozyme electrophoresis still represents a powerful technique in the management of coral reefs. Biodiversity and Conservation. 14: 133-147.

Ridgway, T. (2002). Testing the applicability of molecular genetic markers to population analyses of scleractinian corals. Symbiosis. 33: 243-261.

Ridgway, T., Hoegh-Guldberg, O. and Ayre, D.J. (2001). Panmixia in Pocillopora verrucosa from South Africa. Marine Biology. 139: 175-181.

Professional Associations:

Australian Marine Science Association

Australian Coral Reef Soceity

Australian Diver Accredation Scheme

American Academy of Underwater Science

International Soceity for Reef Studies

Funded Projects:

Connectivity in high latitude coral communities: Understanding processes of recovery

Winifred Scott Estate, 2005-2007, $23,000

Student Projects Available:

Reef connectivity of the high latitude coral communities of SE Queensland

Student Level: Honours Start Year: 2006 Sem Available: 1

Research Collaborators:

RIGINOS Cynthia - Marine Evolutionary Genetics

Students:

BONGAERTS Pim - PhD
KONGJANDTRE Narinratana - PhD - The taxonomy and systematics of corals genus Favia in Thai waters
BONGAERTS Pim - PhD - Ecological significance of deep light-dependent coral communities