Small, cryptic (cryptobenthic) fish communities are a key pathway to productivity: due to their short lifespan, high mortality rates due to predation, high abundance, and varied diets that include detritus, they represent a readily available source of nutrients for higher predators. Despite this central role in reef trophodynamics, much remains unknown about these fish. Most fish surveys have failed to account for this “hidden half” of the reef, and knowledge about how they respond to disturbances is particularly lacking.
The Chagos archipelago is of particular interest for the study of these fish, due to the presence of invasive rats that deplete seabird populations and reduce seabird-derived nutrient subsidies to adjacent reefs, while other islands are rat-free, and feature high seabird densities. Nick Graham, Casey Benkwitt and others have demonstrated how seabird-derived nutrients from these islands leach into the reef and benefit both fish and coral communities.
Following this work, I am interested in comparing cryptobenthic fish communities across rat-free and rat-invaded islands, to test whether nutrient depletion affects cryptobenthic fish’ trophic role. I will also assess connectivity and recruitment processes in cryptobenthic fish communities. Cryptobenthic fish are thought to present limited dispersal, which may lead to local extinction in case of disturbances: we aim to understand whether populations on disturbed reefs can be replenished by larval output from healthy reefs by studying the scale of dispersal of select fish species.
What happens to cryptobenthic fish communities has consequences that extend far beyond what their small size might suggest. How they respond to rat invasion in the Chagos archipelago will inform us of their vulnerability, resistance, and resilience to human-induced changes. This is key for anticipating how higher trophic levels, reef productivity and functioning will be impacted on disturbed reefs – and the potential of underresearched organisms to mitigate or amplify these effects.
Island Reef ConnectionsImplications of Nutrient Flow and Feedback Across the Seabird-Island-Reef System
I am broadly interested in how fish communities respond to disturbances. During my Master’s thesis, I looked at the heritability of anemonefish habitat, which has important consequences under a changing climate. In addition to analysing trophic food webs, I am also interested in using population genetics, an important tool for estimating connectivity and prioritizing areas for conservation. In the long-term, I also hope to contribute to translating scientific knowledge in policy actions and help implement ecologically sound, evidence-based management.