Ascension Island

There is no specific legislation relating to invasive species.

The JNCC database contains 167 non-native species for Ascension Island. This includes 103 plants, 50 invertebrates and nine vertebrates.

Problems with invasive non-native species

Introduced non-native species on the island have caused significant ecological problems. For example, non-native spiders, centipedes and ants have had an impact on the endemic invertebrate species, causing some extinctions. A number of introduced plants are regarded as invasive. For example the Mexican thorn tree (Prosopis juliflora) dominates large parts of the island and out-competes native plants, also leading to soil erosion. (Acacia farnesiana), Guava (Psidium guajava), Prickly pear (Opuntia vulgaris) and Bermuda cedar (Juniperus bermudiaana), all regarded as invasive , are well established in some areas and are likely to exclude any surviving native plant species as are various grass species (eg Greasy grass (Melinis minutiflora), Cow grass (Paspalum scrobiculatum), Cape grass (Sporobolus africanus)). Cottony cushion scale (Icerya purchasi) damages the endemic Ascension Island Spurge (Euphorbia origainoides).

Invasive non-native Prosopis juliflora

Invasive non-native Prosopis juliflora

Mynah birds (Acridotheres tristis) prey extensively on the eggs of native sooty terns Sterna fuscata. Other species such as cats (now eradicated) and rats prey on seabirds and newly emerging turtles. Feral donkeys, sheep and rabbits cause damage to native vegetation and can spread seeds of invasive species.

Non-native Acridotheres tristis

Non-native Acridotheres tristis

Native Sterna fuscata

Native Sterna fuscata

Priority invasive non-native species and actions

The main priorities for action have been to clear invasive plant species in order to allow the regeneration of some endemic plants. Following an island wide botanical survey in 2008 all known examples of Bullgrass (Juncos capillaceus) and Wild Mango (Schinus terebinthifolium) have now been removed. Other action has focussed on the management of Mexican thorn which is widely established in the lowlands. Restoration of local vegetation has also involved excluding grazing animals such as rabbits.


Thin strip of image show tree trunk and bark