Pladaroxylon leucadendron

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	ASTERALES	COMPOSITAE

Scientific Name:

Pladaroxylon leucadendron

Species Authority:

(G. Forst.) Hook. f.

Common Name/s:

English

–

He Cabbage Tree

Taxonomic Notes:

Endemic genus of the Senecioneae, of no certain affinities but allied to Lachanodes (Mabberley 1975).

Assessment Information [top]

Red List Category & Criteria:

Critically Endangered C2a(i)b ver 3.1

Year Published:

2003

Assessor/s:

Cairns-Wicks, R.

Reviewer/s:

Cronk, Q. & Clubbe, C. (South Atlantic Island Plants Red List Authority)

Justification:
P. leucadendron has a patchy distribution across Diana’s Peak National Park and at High Peak. The total subpopulation size at Diana’s Peak National Park was estimated as 80 in 1995 from seven localities, which would impede gene flow. Of the 80, 37 were found at one location, Taylors. Since 1995 most of this group have died, largely because of infestation with moth larva (faecal frass tubes evident on the bark). A seed orchard was planted around this subpopulation in 1998. Since 1995 consistent alien plant control has been carried out as part of a management plan for Diana’s Peak National Park and restocking of the endemic trees including the He cabbage has been carried out. Between 1996 and 1998 160 seedlings and cuttings were planted. Survival rates have not been quantified but observation show that planted stocks do establish and produce healthy growth. None of the planted trees has yet reached maturity. The quality of High Peak habitat is deteriorating and death of trees without recruitment here is highly likely.

History:

1998

–

Critically Endangered (Oldfield et al. 1998)

Geographic Range [top]

Range Description:	Rare tree of the central ridge, at High Peak and from Cuckhold’s Point to Mount Actaeon. Grows at 720 – 800 m but has probably occurred at lower altitudes in the past (Cronk 2000). The total population size is probably less than 50 mature individuals.
Countries:	Native: Saint Helena
Range Map:	Click here to open the map viewer and explore range.

Habitat and Ecology [top]

Habitat and Ecology:	The seed viability of the He Cabbage is variable, which partly explains the low numbers of seedlings raised at the Environmental Conservation Nursery at Scotland and subsequently reintroduced. It is suspected that like the She Cabbage, seed viability is affected by incompatibility magnified by low populations numbers and inbreeding. He cabbage resembles the She Cabbage, which it is allied to (Mabberley 1975) in its soft bark, susceptibility to damage by moth caterpillars and its fast growth and shorter life span compared to the other cabbage trees.
Systems:	Terrestrial

Habitat and Ecology:

The seed viability of the He Cabbage is variable, which partly explains the low numbers of seedlings raised at the Environmental Conservation Nursery at Scotland and subsequently reintroduced. It is suspected that like the She Cabbage, seed viability is affected by incompatibility magnified by low populations numbers and inbreeding. He cabbage resembles the She Cabbage, which it is allied to (Mabberley 1975) in its soft bark, susceptibility to damage by moth caterpillars and its fast growth and shorter life span compared to the other cabbage trees.

Systems:

Terrestrial

Threats [top]

Major Threat(s):	A seed orchard bringing together most of the germplasm of He cabbage has been established at Taylors, however, management of the site has been erratic since 1998. Low subpopulation numbers, small area of occupancy, fragmented distribution, low levels of re-introductions and lack of regular seed collection threaten the recovery of this species.

Major Threat(s):

A seed orchard bringing together most of the germplasm of He cabbage has been established at Taylors, however, management of the site has been erratic since 1998. Low subpopulation numbers, small area of occupancy, fragmented distribution, low levels of re-introductions and lack of regular seed collection threaten the recovery of this species.

Conservation Actions [top]

Conservation Actions:	Protected under the Endangered Endemic and Indigenous Species Protection Ordinance No 7 of 1996. Also protected within the Diana’s Peak National Park which is has been managed under a management plan since 1995 although its still lacks specific legislation the 1998/1999 revision of the SLUP (1993) provides for the protection of the National Park. Regeneration has been successful where invasive plants, such as New Zealand flax, have been cleared.

Conservation Actions:

Protected under the Endangered Endemic and Indigenous Species Protection Ordinance No 7 of 1996. Also protected within the Diana’s Peak National Park which is has been managed under a management plan since 1995 although its still lacks specific legislation the 1998/1999 revision of the SLUP (1993) provides for the protection of the National Park.

Regeneration has been successful where invasive plants, such as New Zealand flax, have been cleared.

Bibliography [top]

	Cronk, Q.C.B. 2000. The Endemic Flora of St. Helena. Anthony Nelson Publishers, Oswestry, UK. IUCN. 2003. 2003 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 18 November 2003. IUCN. 2003. 2003 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 18 November 2003. Mabberley, D.J. 1975. The pachycaul Senecio species of St Helena, Cacalia paterna and Cacalia materna’. Kew Bulletin, 30: 413 – 420 Oldfield, S., Lusty, C. and MacKinven, A. (compilers). 1998. The World List of Threatened Trees. World Conservation Press, Cambridge, UK. Seal, U.S., Maunder, M., Pearce-Kelly, P., Mace, G. and Clark, D. 1993. Conservation assessment and management plan. St. Helena Island. Royal Botanic Gardens, Kew. Smith, D. 1997. The progress and problems of the 'Endemic Section' of St. Helena Island. Oryx 31(3): 218-224. Smith, D. and Williams, N. 1996. Diana’s Peak National Park of St Helena: The Management Plan for 1996–2001. Agriculture and Forestry Department, St Helena.

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

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

Mabberley, D.J. 1975. The pachycaul Senecio species of St Helena, Cacalia paterna and Cacalia materna’. Kew Bulletin, 30: 413 – 420

Oldfield, S., Lusty, C. and MacKinven, A. (compilers). 1998. The World List of Threatened Trees. World Conservation Press, Cambridge, UK.

Seal, U.S., Maunder, M., Pearce-Kelly, P., Mace, G. and Clark, D. 1993. Conservation assessment and management plan. St. Helena Island. Royal Botanic Gardens, Kew.

Smith, D. 1997. The progress and problems of the 'Endemic Section' of St. Helena Island. Oryx 31(3): 218-224.

Smith, D. and Williams, N. 1996. Diana’s Peak National Park of St Helena: The Management Plan for 1996–2001. Agriculture and Forestry Department, St Helena.

Citation:	Cairns-Wicks, R. 2003. Pladaroxylon leucadendron. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 25 May 2012.
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