Euphorbia origanoides

Taxonomy

Assessment Information

Geographic Range

Habitat and Ecology

Threats

Conservation Actions

Bibliography

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
PLANTAE	TRACHEOPHYTA	MAGNOLIOPSIDA	EUPHORBIALES	EUPHORBIACEAE

Scientific Name:

Euphorbia origanoides

Species Authority:

Common Name/s:

English

–

Ascension Spurge

Synonym/s:

Euphorbia berteriana Balb.

Euphorbia origanoides Bertero

Assessment Information [top]

Red List Category & Criteria:

Critically Endangered B1ac(iii,iv)+2ac(iii,iv) ver 3.1

Year Published:

2003

Assessor/s:

Gray, A.

Reviewer/s:

Cronk, Q. & Cairns-Wicks, R. (South Atlantic Island Plants Red List Authority)

Justification:
The last assessment (Cronk 1980) listed E. origanoides as Rare. It should now be considered as Critically Endangered using the new IUCN codes. Information comes from literature sources and personal observation. The population has been stable to increasing over the last five years but as it is known mostly from one location on Ascension it is extremely susceptible to extinction in the near future.

History:

1997

–

Rare (Walter and Gillett 1998)

Geographic Range [top]

Range Description:	Known only from Ascension Island at the South Gannet Hill, Mars Bay, Cross Hill Round Hill, Hummock Point to Spire Beach, Letterbox and Sisters Peak areas. Only common in the South Gannet Hill, Mars Bay, Cross Hill Round Hill areas which contain approximately 93% of the population at present, approximately 2000 plants.
Countries:	Native: Saint Helena (Ascension)
Range Map:	Click here to open the map viewer and explore range.

Habitat and Ecology [top]

Habitat and Ecology:	E. origanoides is found on the dry lava plains of the island from almost sea level to 310 m. This species is characterised by inhabiting the most xeric areas of the island. The distribution of this species has undergone severe changes in recent times (1958-present). Fluctuations in distribution seem to be characteristic of E. origanoides, for example, the colony found at Mars Bay by Duffey in 1958 was not recorded by Cronk (1980), although this colony was again recorded in 1998 and is still present. Aspects of the ecology of E. origanoides is being investigated as part of an environmental impact assessment in 2003.
Systems:	Terrestrial

Habitat and Ecology:

E. origanoides is found on the dry lava plains of the island from almost sea level to 310 m. This species is characterised by inhabiting the most xeric areas of the island. The distribution of this species has undergone severe changes in recent times (1958-present). Fluctuations in distribution seem to be characteristic of E. origanoides, for example, the colony found at Mars Bay by Duffey in 1958 was not recorded by Cronk (1980), although this colony was again recorded in 1998 and is still present. Aspects of the ecology of E. origanoides is being investigated as part of an environmental impact assessment in 2003.

Systems:

Terrestrial

Threats [top]

Major Threat(s):	The presence of the introduced Mexican Thorn Prosopis juliflora represents a serious threat to E. origanoides. This species can spread very rapidly and is very efficient at commanding available ground water with a root depth of over 10 m. The distribution of P. juliflora at present in the E. origanoides areas is limited. The presence of introduced scale insects on a number of plants also presents a threat to some subpopulations. Future road upgrades (in planning at present) through the major subpopulation represents a threat although an impact assessment is being prepared.

Major Threat(s):

The presence of the introduced Mexican Thorn Prosopis juliflora represents a serious threat to E. origanoides. This species can spread very rapidly and is very efficient at commanding available ground water with a root depth of over 10 m. The distribution of P. juliflora at present in the E. origanoides areas is limited. The presence of introduced scale insects on a number of plants also presents a threat to some subpopulations. Future road upgrades (in planning at present) through the major subpopulation represents a threat although an impact assessment is being prepared.

Conservation Actions [top]

Conservation Actions:	Aspects of the ecology of E. origanoides are being investigated in 2003 as part of an environmental impact assessment by Alan Gray. The population is under cultivation and surveillance by Ascension Conservation.

Conservation Actions:

Aspects of the ecology of E. origanoides are being investigated in 2003 as part of an environmental impact assessment by Alan Gray. The population is under cultivation and surveillance by Ascension Conservation.

Bibliography [top]

	Ashmole, P. and Ashmole M. 2000. St Helena and Ascension Island: a natural history. Anthony Nelson, Oswestry, UK. Cronk, Q.C.B. 1980. Extinction and survival in the endemic flora of Ascension Island. Biological Conservation 17(3): 207-219. Cronk, Q.C.B. 1992. Relict floras of Atlantic Islands: patterns assessed. Biological Journal of the Linnean Society. 46: 91-103. Cronk, Q.C.B. 1997. Islands: stability, diversity, and conservation. Biological Conservation. 6: 477-493. Cronk, Q.C.B. 2000. The Endemic Flora of St. Helena. Anthony Nelson Publishers, Oswestry, UK. Duffey, E. 1964. The terrestrial ecology of Ascension Island. Journal of Applied Ecology 1: 219-251. Gray, A., Gardner, S., Kirk, L., Robinson, P., Smölka, Z. and Webster, L. 2000. The status and distribution of the endemic vascular flora of Ascension Island. Unpublished Report. IUCN. 2003. 2003 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 18 November 2003. White, R, and George, T. 2002. Status of endemic plants on Ascension Island in 2002. Ascension Conservation Draft Report.

Ashmole, P. and Ashmole M. 2000. St Helena and Ascension Island: a natural history. Anthony Nelson, Oswestry, UK.

Cronk, Q.C.B. 1980. Extinction and survival in the endemic flora of Ascension Island. Biological Conservation 17(3): 207-219.

Cronk, Q.C.B. 1992. Relict floras of Atlantic Islands: patterns assessed. Biological Journal of the Linnean Society. 46: 91-103.

Cronk, Q.C.B. 1997. Islands: stability, diversity, and conservation. Biological Conservation. 6: 477-493.

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

Duffey, E. 1964. The terrestrial ecology of Ascension Island. Journal of Applied Ecology 1: 219-251.

Gray, A., Gardner, S., Kirk, L., Robinson, P., Smölka, Z. and Webster, L. 2000. The status and distribution of the endemic vascular flora of Ascension Island. Unpublished Report.

IUCN. 2003. 2003 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 18 November 2003.

White, R, and George, T. 2002. Status of endemic plants on Ascension Island in 2002. Ascension Conservation Draft Report.

Citation:	Gray, A. 2003. Euphorbia origanoides. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 25 May 2012.
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