Endemic flora

Seven endemic vascular plant species remain on Ascension out of an original ten that have been scientifically described since humans first discovered the island in 1501. In addition, at least sixteen of Ascension’s eighty native mosses, liverworts and hornworts are endemic

Ascension’s endemic plants adapted to colonise a young volcanic landscape, isolated from most competitors, pests and herbivores. Dramatic changes to the island since human arrival, including the introduction of goats, rats, mice and over 400 plant species, have reduced and fragmented the ranges of many endemics.

With the few remaining sub-populations isolated and limited in genetic diversity, they are increasingly prone to extinction and potentially more vulnerable to climate change. Moreover, rain is scarce on Ascension. Already pushed to remote, dry fringes of the arid lowlands, an increased drought risk could present a major risk to the Ascension spurge, Euphorbia origanoides. Meanwhile, endemic plants that grow on Green Mountain, the island’s highest peak, rely on fog near the summit for moisture. If climate change raises the cloud level and leaves the mountain immersed in fog less often, fog-dependent ferns, grasses and bryophytes are likely to suffer from more frequent and prolonged droughts.