This project involves surveying the environs of all the islands within St Joseph Atoll for potential sites where mangroves could be re-introduced, planting mangroves at these sites and monitoring the success of the restoration attempts and the growth rates of the mangroves. Mangrove propagules are planted at the restoration sites and their growth is monitored over time. Important aspects of the study are to understand where in St Joseph Atoll mangroves occurred in the past and to identify the environmental conditions and habitat features that support their growth and success; this will help us to draft future plans for the habitat.
Since its inception in 2012, the SOSF-DRC has been managed and run by different people in various capacities. Lab managers, research officers and research assistants have been integral to the daily operations of the centre over these years and our long-term projects have been handed on from past to present management.
Currently the SOSF-DRC is run by Dr Robert Bullock and Henriette Grimmel in a joint-management capacity.
The following is a history of past management staff:
The key objective of the project is to study the distribution, abundance, ‘ecological use’ and growth rate of mangroves in St Joseph Atoll.
Understanding the past and current state of this ecosystem is essential for the preservation of the habitat, its associated species and the services the habitat provides now and in the future. Research into mangroves is complementary to other long-term SOSF-DRC projects, especially those concerned with sharks and rays, as mangroves are known to be a key habitat for these species. St Joseph Atoll also offers a template study site as an Indian Ocean coralline island where data on growth rates of mangroves can be acquired and will contribute to mangrove restoration science for the region.
Mangroves are important coastal features in tropical habitats, providing a multitude of ecosystem services and acting as nurseries and important feeding grounds for many species. Despite this, they are highly threatened and over the past 50 years mangrove habitat has declined rapidly around the world. Mangrove restoration projects like the one initiated at St Joseph aim to mitigate these losses and restore important mangrove habitat.
Mangrove ecosystems provide a variety of services to both people and animals. Science shows that mangroves provide important nurseries and habitats to many marine species, such as reef fish, rays and sharks. Mangroves act as buffers against strong wave energy during storms and protect coastlines, while at the same time preventing harmful terrestrial sediments from settling in the ocean. The benefits of mangroves are numerous and include their capacity to sequestrate carbon, the value of which is widely acknowledged. In addition, recent research suggests that corals adjacent to mangroves are at an advantage during bleaching events, as mangroves provide valuable nutrients that are taken up by corals as a secondary food source. Although the past extent of mangroves at St Joseph is poorly documented, we do know that the atoll is currently home to a great number of juvenile sharks and rays. Mangrove thickets are known to provide crucial habitat, especially for neonates and juveniles, as they can offer safety from larger predators and are rich in potential food sources.
The key objective of this project is met by several specific study objectives:
– To investigate the historical range of mangroves prior to the planting of coconut trees within St Joseph Atoll.
– To survey and map the current distribution and abundance of mangrove species occurring within St Joseph Atoll.
– To identify and establish restoration sites for red mangroves.
– To investigate correlations between success and growth rates of mangroves under differing environmental conditions at different restoration sites to inform future practice.
Dillys will be collecting plankton samples and environmental data around D’Arros island and St. Joseph atoll, where highly resident reef manta rays feed, to quantify the prey density threshold. She will process these samples in the lab and use the biomass data to estimate the prey density threshold; and using the environmental data, she will also identify potential drivers of prey density patterns. This will provide insights on reef manta ray feeding ecology globally.
This project will investigate the scale at which structural complexity correlates with coral reef productivity and how this varies spatially in an isolated and largely unperturbed reef system. The project will further explore the application of structure-from-motion photogrammetry to quantifying spatial gradients in reef complexity and bleaching extent.
I will be using drones on St Joseph Atoll, to conduct aerial population densities of both green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) sea turtles, whilst outlining which habitat types are occupied by each species. I will use this information to produce habitat management recommendations that will be applicable in other areas of the Seychelles, as well as on a global scale.