Elaphoglossum dimorphum

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
PLANTAE	POLYPODIOPHYTA	POLYPODIOPSIDA	BLECHNALES	LOMARIOPSIDACEAE

Scientific Name:	Elaphoglossum dimorphum
Species Authority:	(Hook. & Grev.) Moore
Taxonomic Notes:	Close relative of Elaphoglossum nervosum and Elaphoglossum bifurcatum, which are also endemic to St Helena. Preliminary research indicated that the species is of hybrid origin between E. nervosum and E. birfurcatum. This may explain its rarity.

Assessment Information [top]

Red List Category & Criteria:	Critically Endangered D ver 3.1
Year Assessed:	2004
Assessor/s:	Eastwood, A.
Reviewer/s:	Cairns-Wicks, R. & Clubbe, C. (South Atlantic Islands Plant RLA); Mickel, J. & Moran, R. (Pteridophyte RLA)
Justification: The world population of Elaphoglossum dimorphum is < 50 mature individuals, comprising two subpopulations in Diana’s Peak National Park. A number of individuals have also been observed at the Depot and High Peak but this requires verification. The information on population sizes and distribution is based on fieldwork conducted on the species in 1999 and 2000 as part of a Ph.D. (Eastwood 2003, Eastwood et al. 2004a, Eastwood et al. 2004b) and takes into consideration Cronk (2000) which uses the pre-1994 IUCN Categories.

Geographic Range [top]

Range Description:	Restricted to two main subpopulations in Diana’s Peak National Park, one at Mount Actaeon and one at Cuckold’s Point. Occasional plants have also been observed at High Peak and the Depot but these require verification. Extent of occurrence < 5 km², if individuals at High Peak and Depot included. The two subpopulations comprise 34 and 12 individuals respectively with occasional plants at High Peak and the Depot.
Countries:	Native: Saint Helena

Range Description:

Restricted to two main subpopulations in Diana’s Peak National Park, one at Mount Actaeon and one at Cuckold’s Point. Occasional plants have also been observed at High Peak and the Depot but these require verification. Extent of occurrence < 5 km², if individuals at High Peak and Depot included. The two subpopulations comprise 34 and 12 individuals respectively with occasional plants at High Peak and the Depot.

Countries:

Native:

Saint Helena

Population [top]

Population Trend:	Stable

Population Trend:

Stable

Habitat and Ecology [top]

Habitat and Ecology:	Terrestrial fern found growing on stone steps, rocks and shaded mossy banks in tree fern thicket. Found in close proximity to the other two endemic Elaphoglossum (E. nervosum and E. bifurcatum). Evidence from allozymes indicate that the species maybe of hybrid origin between E. nervosum and E. birfurcatum. This may explain its rarity.
Systems:	Terrestrial

Threats [top]

Major Threat(s):	Population size is probably restricted by suitable habitat. The main threat to the species is encroachment of invasive exotics such as Phormium tenax (New Zealand Flax).

Major Threat(s):

Population size is probably restricted by suitable habitat. The main threat to the species is encroachment of invasive exotics such as Phormium tenax (New Zealand Flax).

Conservation Actions [top]

Conservation Actions:	Majority of the population is in Diana’s Peak National Park which has been actively managed for the past 10 years. This has included extensive clearance of invasive exotics and planting of native species. The regeneration of tree fern thicket into cleared areas is notable.

Conservation Actions:

Majority of the population is in Diana’s Peak National Park which has been actively managed for the past 10 years. This has included extensive clearance of invasive exotics and planting of native species. The regeneration of tree fern thicket into cleared areas is notable.

Citation:	Eastwood, A. 2004. Elaphoglossum dimorphum. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 09 February 2012.
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