However the seabird populations on Ascension Island itself have been severely affected by introduced species, especially cats, which were the subject of an eradication campaign between 2002 and 2006.

Endemic species include two shrubs (Euphorbia origanoides and Oldenlandia adscensionis (possibly extinct)), two grasses (Sporobolus durus (possibly extinct) and Sporobolus caespitosus), and six ferns (Asplenium ascensionis, Marattia purpurascens, Xiphopteris ascensionense, Pteris adscensionis, and Anogramma ascensionis).

The Ascension Island Conservation Department are working in collaboration with the Royal Botanic Garden, Kew on an OTEP (Overseas Territories Environmental Programme) funded Endemic Plants project.

Experts from the UK Overseas Territories Team at Kew advise on propagation techniques, ex-situ cultivation and the re-introduction of endangered species.

The protocols require a lot of trial and error work to identify the most successful propagation methods for the endemic plants.

Stedson Stroud has already successfully cultivated in large numbers three of the endemic species, Pteris adscensionis, Euphorbia origanoides and Sporobolus caespitosus.

The project work focuses on increasing the number of endemic species growing in cultivation and introducing these into the restoration areas.

The present size of the seabird populations are only a fraction of those found before the colonisation by man in 1815 and the subsequent introduction of feral cats to the Island.

Predation by rodents and invertebrates on the mainland has limited its distribution to the very isolated Boatswainbird Island, where it lives alongside the endemic frigatebird.

Meanwhile, the Mexican thorn bush (Prosopis juliflora), another introduced species, has become a serious impediment to the breeding turtles, who lay their eggs on the beaches, and housing development on the island threatens many habitats.

Invasive species Mexican thorn (Prosopis juliflora) This shrub was introduced to stabilise land near new buildings in Two Boats village during the 1960s.

It has completely replaced the native vegetation in these areas and threatens bird grounds as well as turtle laying beaches.

It can tolerate both hot desert areas as well as cool moist mountain air, and forms thickets that compete with native plants for water and light.

Koster's curse (Clidemia hirta) This is one of the species that now occurs where a carpet of native and endemic ferns used to grow on Green Mountain.

They abound in all parts of the Island, feeding on endemic as well as introduced plants, preying on small animals and competing with land crabs.