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Nesiota elliptica 

Scope: Global
Language: English
Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_offStatus_vu_offStatus_en_offStatus_cr_offStatus_ew_offStatus_ex_on

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Rhamnales Rhamnaceae

Scientific Name: Nesiota elliptica
Species Authority: (Roxb.) Hook.f.
Common Name(s):
English St Helena Olive
Synonym(s):
Phylica elliptica Roxb.

Assessment Information [top]

Red List Category & Criteria: Extinct ver 3.1
Year Published: 2016
Date Assessed: 2015-06-13
Assessor(s): Lambdon, P.W. & Ellick, S.
Reviewer(s): Clubbe, C.P.
Contributor(s): Cairns-Wicks, R.
Justification:
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:

Geographic Range [top]

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.
Countries occurrence:
Regionally extinct:
Saint Helena, Ascension and Tristan da Cunha (Saint Helena (main island))
Additional data:
Estimated area of occupancy (AOO) - km2:0
Number of Locations:0
Lower elevation limit (metres):650
Upper elevation limit (metres):820
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:

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.

(*There is some controversy of the naming of the three summits in the Diana’s Peak range. We here refer to Mt Actaeon as the most northerly in the series.)

Additional data:
Number of mature individuals:0

Habitat and Ecology [top]

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.).

The flowering period was variable but was probably mainly restricted to the winter months. The small blooms were mainly pollinated by hoverflies, and matured into dry capsules which took up to a year to ripen (Jackson 1991).

Systems:Terrestrial
Movement patterns:Not a Migrant

Use and Trade [top]

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.

Threats [top]

Major Threat(s):

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.

Once severely reduced in numbers, small population size appears to have created further, inherent problems through low self-compatibility and perhaps also through inbreeding depression which may have reduced resilience to pests. It is entirely possible that susceptibility to introduced fungal pathogens may have played a longer term role in the overall demise.

Conservation Actions [top]

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.

Classifications [top]

1. Forest -> 1.9. Forest - Subtropical/Tropical Moist Montane
suitability:Suitable season:resident major importance:Yes

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
In-Place Species Management
In-Place Education
12. Other options -> 12.1. Other threat
♦ timing:Past, Unlikely to Return ♦ scope:Whole (>90%) ♦ severity:Unknown ⇒ Impact score:Past Impact 
→ Stresses
  • 1. Ecosystem stresses -> 1.3. Indirect ecosystem effects
  • 2. Species Stresses -> 2.3. Indirect species effects -> 2.3.5. Inbreeding
  • 2. Species Stresses -> 2.3. Indirect species effects -> 2.3.7. Reduced reproductive success

2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.3. Agro-industry farming
♦ timing:Past, Unlikely to Return ♦ scope:Minority (<50%) ♦ severity:Very Rapid Declines ⇒ Impact score:Past Impact 
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation
  • 1. Ecosystem stresses -> 1.3. Indirect ecosystem effects
  • 2. Species Stresses -> 2.1. Species mortality
  • 2. Species Stresses -> 2.3. Indirect species effects -> 2.3.2. Competition

2. Agriculture & aquaculture -> 2.3. Livestock farming & ranching -> 2.3.2. Small-holder grazing, ranching or farming
♦ timing:Past, Unlikely to Return ♦ scope:Minority (<50%) ♦ severity:Very Rapid Declines ⇒ Impact score:Past Impact 
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 2. Species Stresses -> 2.1. Species mortality

5. Biological resource use -> 5.3. Logging & wood harvesting -> 5.3.1. Intentional use: (subsistence/small scale) [harvest]
♦ timing:Past, Unlikely to Return ♦ scope:Unknown ♦ severity:Very Rapid Declines ⇒ Impact score:Past Impact 
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation
  • 2. Species Stresses -> 2.1. Species mortality

8. Invasive and other problematic species, genes & diseases -> 8.1. Invasive non-native/alien species/diseases -> 8.1.1. Unspecified species
♦ timing:Past, Unlikely to Return ♦ scope:Majority (50-90%) ♦ severity:Slow, Significant Declines ⇒ Impact score:Past Impact 
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation
  • 1. Ecosystem stresses -> 1.3. Indirect ecosystem effects
  • 2. Species Stresses -> 2.3. Indirect species effects -> 2.3.2. Competition

8. Invasive and other problematic species, genes & diseases -> 8.4. Problematic species/disease of unknown origin -> 8.4.1. Unspecified species
♦ timing:Past, Unlikely to Return  ♦ severity:Slow, Significant Declines  
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

Bibliography [top]

Beatson, A. 1816. An alphabetical list of plants seen by Dr Roxburgh growing on the island of St Helena. Tracts relative to the Island of St Helena, Appendix 1. W.Bulmer & Co., London, U.K.

Burchell, W.J. 1805-10. Flora Insulae Sanctae Helenae. Unpublished manuscript held at Royal Botanic Gardens Kew, Richmond, U.K.

Cairns-Wicks, R. 2004. Nesiota elliptica. The IUCN Red List of Threatened Species 2004: e.T37598A10062366. doi: /10.2305/IUCN.UK.2004.RLTS.T37598A10062366.en.

Cronk, Q.C.B. 2000. The Endemic Flora of St. Helena. Anthony Nelson Publishers, Oswestry, UK.

IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-1. Available at: www.iucnredlist.org. (Accessed: 30 June 2016).

Jackson, A. 1991. Project Popeye – Saving the St Helena Olive. Preliminary report to the World Wide Fund for Nature. WWF Project No. 162/89. Wakehurst Place, RBG, Kew.

Lambdon, P. 2012. Flowering Plants and Ferns of St Helena. Pisces Publications, Newbury, UK.

Melliss, J.C. 1875. St Helena: A Physical, Historical and Topographical Description of the Island, Including its Geology, Fauna, Flora and Meteorology. L. Reeve & Co., London, U.K.

Royal Botanic Gardens, Kew. 2009. Data extracted from notes accompanying collection of herbarium specimens. Accessed 2009. Royal Botanic Gardens, Kew, London.


Citation: Lambdon, P.W. & Ellick, S. 2016. Nesiota elliptica. The IUCN Red List of Threatened Species 2016: e.T37598A67372241. . Downloaded on 08 December 2016.
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