Assessing the Marine Biodiversity of the Ascension Islands

Introducing an exciting marine survey of one of the world's most remote islands.

Ascension Island, an isolated volcanic island in the equatorial waters of the South Atlantic, around 1,600 kilometres from the coast of Africa and 2,250 kilometres from the coast of South America, harbours globally important biodiversity, potentially representing a unique assemblage of western and eastern Atlantic flora and fauna. Previous biodiversity projects focused on sea-turtles, seabirds and plants and marine biodiversity remains virtually unknown; searches for scientific records show few if any collective studies on the Island’s benthic species, habitats or biogeography. A small Conservation Department comprising 3 core staff was created in 2001 and has carried out much work, however, critical work remains. The Island lacks a National Biodiversity Strategy.

[caption id="attachment_27" align="alignnone" width="584"] The main island has an area of approximately 91 square km and consists of a volcanic peak rising from just west of the Mid-Atlantic Ridge. Much of the island is a wasteland of lava flows and cinder cones; no fewer than forty-four distinct dormant craters have been identified.

Lacking are inventories of marine invertebrates, ichthyofauna and algae. Habitat inventories and mapping are needed to manage coastal zones. Additionally, corals and associated fauna are particularly sensitive to climate change. The status of marine endemic species is absent and redressing these will drive the formulation of species actions plans. As an initial survey, our objectives are to generate baseline data, thus creating scope for future marine biodiversity conservation and management projects on the Island. We will train local divers and Conservation Professionals in sampling protocols such that the collection of baseline data and monitoring of key marine flora and fauna can continue.

We have assembled a dedicated team of 24 local and international ecologists, taxonomists and divers. Many of the team have worked successfully together previously as project partners in the Falkland Islands and South Georgia. The logistics of transporting personnel and equipment is currently being developed with British Forces project partners.

[caption id="attachment_25" align="alignnone" width="584"] Each year on Ascension Island between 6,000 and 15,000 nests are laid by the endangered Green Turtle (Chelonia mydas) making this the second largest nesting colony of this species in the Atlantic Ocean. Egg laying the previous night has left this small beach covered with nesting pits.

The basis of the study is an ambitious three week (21 day) expedition to the Islands to survey the intertidal and sub-tidal zones down to 30m depth. We will adapt successful protocols from our previous work, (quantitative photo-quadrats, collections, macro-photography) and employ established methods specific to coral reef habitats (belt transects, fish counts). Our experts will attempt to identify all georeferenced samples taken during the survey and used to generate habitat classification schemes and maps.

Results from the survey will result in faunal and floral species inventories, habitat descriptions and maps, a field guide to marine invertebrates, algae and fish, a report on the status of marine endemics, and a report on the potential impacts of climate change. These will inform Ascension Island Government of how they can fit their shallow marine environment into future biodiversity strategies.