I have been working in the Chagos Archipelago since 2006. Much of my work focussed on the reef fish community, and how the biomass and structure of fish communities in Chagos compares to other reefs across the Indian Ocean in smaller Marine Protected Areas (MPAs) and fished seascapes. I have also assessed how changes in the coral condition influences the fish communities, changes in reef shark abundance and documented unique or extreme fish behaviours.
I have recently become interested, in conjunction with Dr. Casey Benkwitt, in the influence of seabird guano on the coral reefs. On some islands invasive rats have decimated seabird populations, whereas where rats are absent, seabirds’ densities can be more than 700 times greater. Seabirds feed predominantly in the pelagic ocean and return to the islands to nest, breed and roost where they deliver large quantities of nutrients (guano).
I have shown how these nutrients leach onto adjacent coral reefs, leading to faster fish growth, 50% more biomass, and higher rates of key ecosystem processes on reefs adjacent to islands with seabirds, compared to those with rats.
Eradicating invasive rats from tropical islands is likely to cause a return of large populations of seabirds, and the nutrients they deliver will benefit adjacent coral reef benthic and fish communities.
Coral Reef ResilienceCoral Reef Fish in the British Indian Ocean Territory
Much of my work is in the central and western Indian Ocean region, but I also have ongoing projects in the Pacific and am working on some global analyses.
I am investigating the changing ecology and functioning of coral reefs. This research aims to assess the changing ecology of coral reef ecosystems in relation to increasing man-made pressure. Specifically, we are quantifying the changing composition of coral reefs in response to climate change and other human impacts, assessing how the top-down (i.e. fishing) versus bottom-up (i.e. habitat composition) influences the productivity of coral reef fisheries. We also evaluate how ecosystem functions differ under alternate scenarios of direct human use and climate impacts.
Additionally, I also work on linking coral reef social-ecological systems. Many solutions to environmental problems lie in understanding the interaction between humans and the environment. This research tackles issues such as identifying the underlying social drivers behind marine ecosystem condition, uncovering the socio-ecological outcomes differing management approaches, assessing the influence of ecosystem change on the delivery of ecosystem services to people and uncovering how coral reef fisheries can be managed to improve food security.