|Scientific Name:||Nesiota elliptica (Roxb.) Hook.f.|
Phylica elliptica Roxb.
|Red List Category & Criteria:||Extinct ver 3.1|
|Assessor(s):||Lambdon, P.W. & Ellick, S.|
The St Helena Olive (Nesiota elliptica) is almost certainly Extinct. The population was extremely small for at least 120 years before the final tree died in 1994. Well under 1 km2 of suitable habitat remains along St Helena’s Central Ridge and this has been searched extensively by botanists over recent decades.
|Previously published Red List assessments:|
|Range Description:||The St Helena Olive formerly occurred in the uplands of St Helena, South Atlantic Ocean. So few specimens survived to the historical period that the original range is difficult to reconstruct. Nearly all old records are from the Diana’s Peak area, although Roxburgh also noted it from “the Sandy Bay range” (see Beatson 1816), presumably meaning that it was more widely distributed along the Central Ridge.|
Regionally extinct:Saint Helena, Ascension and Tristan da Cunha (Saint Helena (main island))
|Range Map:||Click here to open the map viewer and explore range.|
Intact fragments of St Helena Olive habitat probably persisted until the late 1800s, when Solander noted trees up to 30 foot high (approx. 9 m) (see Cronk 2002). A century later, only 12-15 trees remained, and these reputedly attained little more than half the former stature (Melliss 1875). When George Benjamin discovered a single specimen near Mt Actaeon* in 1977 the species had not been seen for many years. This proved to be the last known wild specimen in existence. It died in 1994 but seedlings and a cutting had been propagated from it, and a few cultivated individuals continued the line. Unfortunately these did not survive long, the last succumbing to fungal infections in 2003.
|Habitat and Ecology:|
Based on existing evidence, it appears that this species was an inhabitant of cloud forest around St Helena’s highest altitudes (above 750 m). The 20th Century specimen at Mt Actaeon grew in Tree Fern thicket (Cronk 2002), but it is also likely to have occurred in more mixed vegetation with other upland trees on steep slopes below the ridge crest. As the high altitude zone comprises the last vestiges of native forest on St Helena, there remains a possibility that the final individuals were relicts along the upper altitudinal edge of the former range and that the natural distribution would have extended to lower altitudes. However, the Olive certainly seemed to be a regular cloud forest species and a more natural member of this community than other postulated ‘transitional zone’ trees such as Redwood (Trochetiopsis erythroxylon (G.Forst.) Marais) and She Cabbage (Lachanodes arborea (Roxb.) B.Nord.).
|Movement patterns:||Not a Migrant|
|Use and Trade:||The wood was undoubtedly used for timber, but the harvest is unlikely to have been regular since the mid 19th Century as specimens have become increasingly scarce.|
The majority of the population was probably lost to deforestation following the establishment of a permanent colony on St Helena by the East India Company in 1658. Trees were cleared for pasture land and also to provide fuel and timber, for which the hard, yellow wood was probably reasonably prized. Only fragments of the original mid-altitude forest cover remained by the mid 18th Century, and by the time of Melliss’s records in the late 1800s there was little native vegetation away from the highest elevations. Further extensive damage was inflicted in the 20th Century when large plantations of New Zealand flax (Phormium tenax J.R.Forst. & G.Forst.) were established over the steep slopes of the Central Ridge, although it appears that the species was already close to extinction by this time.
|Conservation Actions:||After the rediscovery of the single tree in 1977, an intensive rescue attempt was mounted in with expert help from the Royal Botanic Gardens, Kew (Jackson 1991). They found that the species possessed a self-incompatibility breeding system resulting in less than 1% fertility. It consequently proved difficult to raise seedlings, and only one out of hundreds of cuttings was successful. Fungal infections killed the wild tree and blighted attempts to rear plants in cultivation, eventually leading to the death of the last daughter individual.|
|Citation:||Lambdon, P.W. & Ellick, S. 2016. Nesiota elliptica. The IUCN Red List of Threatened Species 2016: e.T37598A67372241.Downloaded on 20 October 2017.|