Marattia purpurascens

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Bibliography

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
PLANTAE	POLYPODIOPHYTA	POLYPODIOPSIDA	MARATTIALES	MARATTIACEAE

Scientific Name:	Marattia purpurascens
Species Authority:	de Vriese

Assessment Information [top]

Red List Category & Criteria:

Near Threatened ver 3.1

Year Published:

2003

Assessor/s:

Gray, A.

Reviewer/s:

Cronk, Q., Cairns-Wicks, R. (South Atlantic Island Plants Red List Authority) & Jermy, C., Ranker, T. (Pteridophyte Red List Authority)

Justification:
The last assessment (Cronk 1980) listed M. purpurascens as Rare. It should now be considered as Near Threatened using the new IUCN codes. Information comes from literature sources and personal observation. The population is assumed to be stable but no direct measurements have been made, this stability is the reason it is considered as Near Threatened. The species could qualify for Vulnerable D2, however, the risk of extinction would appear to be over the very long term rather than the short to medium term.

History:

1997

–

Rare (Walter and Gillett 1998)

Geographic Range [top]

Range Description:	Known only from the weather side of the Green Mountain area of Ascension Island, South Atlantic Ocean. Occupies an area less than 0.5 km². Sole population found on the weather side of Green Mountain where it is common amongst grassland, scrub and underneath bamboo. Population appears stable and must number several hundred plants.
Countries:	Native: Saint Helena (Ascension)
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population Trend:	Stable

Population Trend:

Stable

Habitat and Ecology [top]

Habitat and Ecology:	M. purpurascens is found on the weather side of Green Mountain growing in the open grassland and amongst the dense stand of bamboo at the summit, from an altitude of approximately 700 to 859 m. M. purpurascens is physically the largest of all the endemic species on Ascension and appears to be able to compete favourably with other exotic species, possessing a degree of phenotypic plasticity that may contribute to its survival (Cronk 1980). This plasticity is evident when comparing individuals amongst the bamboo near the summit with those on the more open grassland. The former tends to be smaller and darker, whereas the latter are lighter in colour and larger.
Systems:	Terrestrial

Habitat and Ecology:

M. purpurascens is found on the weather side of Green Mountain growing in the open grassland and amongst the dense stand of bamboo at the summit, from an altitude of approximately 700 to 859 m. M. purpurascens is physically the largest of all the endemic species on Ascension and appears to be able to compete favourably with other exotic species, possessing a degree of phenotypic plasticity that may contribute to its survival (Cronk 1980). This plasticity is evident when comparing individuals amongst the bamboo near the summit with those on the more open grassland. The former tends to be smaller and darker, whereas the latter are lighter in colour and larger.

Systems:

Terrestrial

Threats [top]

Major Threat(s):	There do not appear to be any immediate threats to the persistence of M. purpurascens. Longer-term threats are more difficult to detect and will only become apparent by implementing long term monitoring. The survival of M. purpurascens is dependent on its ability to compete with introduced vegetation. Certainly over the past twenty years no great changes in distribution are apparent, implying a degree of competitive ability. Some plants do appear to be grazed by sheep but this is not a widespread or common occurrence and does not appear to be contributing to mortality. Large-scale habitat destruction would be disastrous for the localised subpopulations, however, this seems unlikely at present.

Major Threat(s):

There do not appear to be any immediate threats to the persistence of M. purpurascens. Longer-term threats are more difficult to detect and will only become apparent by implementing long term monitoring. The survival of M. purpurascens is dependent on its ability to compete with introduced vegetation. Certainly over the past twenty years no great changes in distribution are apparent, implying a degree of competitive ability. Some plants do appear to be grazed by sheep but this is not a widespread or common occurrence and does not appear to be contributing to mortality. Large-scale habitat destruction would be disastrous for the localised subpopulations, however, this seems unlikely at present.

Conservation Actions [top]

Conservation Actions:	Population is under surveillance by Ascension Conservation.

Conservation Actions:

Population is under 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. Marattia purpurascens. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 25 May 2012.
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