Secamone schimperiana 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Gentianales Asclepiadaceae

Scientific Name: Secamone schimperiana (Hemsl.) Klack.
Toxocarpus schimperianus Hemsl.

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii)+2ab(iii) ver 3.1
Year Published: 2011
Date Assessed: 2007-02-01
Assessor(s): Ismail, S., Huber, M.J. & Mougal, J.
Reviewer(s): Hilton-Taylor, C. & Lutz, M.L.
Secamone schimperiana only known from Mahé, Praslin and Curieuse, the Seychelles. The total estimated extent of occurrence (EOO) and the area of occupancy (AOO) are less than 100 km². The species occurs in scrub and rocky areas between 50 and 500 m altitude. This habitat is heavily invaded by introduced species (e.g., Chrysobalanus icaco) affecting habitat quality. Additionally, the low land habitats are strongly affected by development for housing and tourism. A continuing decline in the quality and extent of its habitat has to be assumed as at least the Mahé subpopulation is declining. It is therefore listed as Endangered.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to the Seychelles. It is only known from Mahé, Praslin and Curieuse (Friedmann 1994). The EOO on Mahé is estimated to be 1 km² (Mont Sébert) or at maximum 6.7 km² (if one counts the record from Casse Dent, where the species could not be found in recent years). The EOO on Praslin and Curieuse was not determined. The total area of Praslin is only 38 km² and the area of Curieuse is 2.7 km² (National Statistics Bureau 2005). The total estimated EOO and AOO are therefore both less than 100 km².
Countries occurrence:
Seychelles (Seychelles (main island group))
Additional data:
Estimated area of occupancy (AOO) - km2:50-100
Number of Locations:3
Lower elevation limit (metres):50
Upper elevation limit (metres):500
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Estimates of the population size have to be interpreted cautiously because the species mainly reproduces vegetative. The effective number of genotypes could be extremely low. On Praslin (Fond Diable towards Anse Gouvernment) the best-developed subpopulation consists of 500 to 1,000 individuals. The other two known sites on Praslin consist of five and two plants respectively. On Curieuse, small patches of plants can be found consisting of fewer than 15 plants. The total population on Curieuse must be smaller than 100 individuals (L. Chong Seng pers. comm. 2006). The only written record about the subpopulation on Curieuse stated that in1990 approximately 40 individuals were recorded and that poor reproduction was observed (Carlström 1996).

On Mahé, S. schimperiana is close to extinction and at the present stage only two sites with a few individuals are known (Mt. Sébert). Several searching efforts in the Casse Dent area could not confirm former records made in this area (F. Fleischer-Dogley pers. comm. 2006). On Mont Sébert, fewer than 50 individuals are thought to occur and if the species still occurs in the Casse Dent area there must be fewer than 10 individuals (L. Chong Seng pers. comm. 2006). The population size is therefore estimated to be between 600 and 1,200 mature individuals.

Historical records are only known from Mahé (Summerhayes 1931). In 1974, the species was thought to be extinct on Mahé (Procter 1974). In 1994, the species was recorded at six sites on Mahé, Praslin and Curieuse. Based on these records no future or past decline can be quantified.
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:600-1200

Habitat and Ecology [top]

Habitat and Ecology:The species occurs in scrub and rocky areas between 50 and 500 m altitude. The seeds are wind dispersed, a rather uncommon phenomenon in small island ecosystem where the seeds area easily blown to the sea (Carlström 1996). The chance that propagules are exchanged successfully between the islands is extremely unlikely.

Threats [top]

Major Threat(s): Invasion of alien species, low densities and restricted range are the main threats to this species. On Praslin, fires have to be regarded as an additional main threat. The scrub habitat at low and intermediate altitude, where this species occurs, is heavily invaded by introduced species (e.g., Chrysobalanus icaco). Additionally, the low land habitats are strongly affected by development for housing and tourism.

Conservation Actions [top]

Conservation Actions: The species occurs in the Morne Seychellois National Park, in the Praslin National Park and Curieuse Marine National Park.

Citation: Ismail, S., Huber, M.J. & Mougal, J. 2011. Secamone schimperiana. The IUCN Red List of Threatened Species 2011: e.T191545A8843851. . Downloaded on 26 September 2017.
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