|Scientific Name:||Martellidendron hornei|
|Species Authority:||(Balf.f.) Callm. & Chassot|
Pandanus hornei Balf.f.
|Red List Category & Criteria:||Vulnerable A2c; D2 ver 3.1|
|Assessor(s):||Ismail, S., Huber, M.J. & Mougal, J.|
|Reviewer(s):||Gibbs, D. & Lutz, M.L.|
Martellidendron hornei occurs on five islands: Mahé, Praslin, Silhouette, La Digue and Curieuse. In 1899, it was described to often occur in large numbers in damp forests and was an essential feature of the Seychelles landscape. Nowadays, it is mainly found in small groups, which are mostly confined to river ravines and on slopes where there is good access to water. Based on this historical comparison it is obvious that there has been a massive population reduction of at least 30% in the last 100 years (during the last three generations). Wetland clearance for cultivation may have been the main reason for this reduction. Ongoing threats are caused by effects of introduced taxa. This tree is therefore listed as Vulnerable.
|Previously published Red List assessments:||
|Range Description:||Endemic to Seychelles, M. hornei occurs on five islands: Mahé, Praslin, Silhouette, La Digue and Curieuse (Robertson 1989, Dogley and Matatiken 2006). The measured extent of occurrence (EOO) on Mahé is 77 km². The total area of the other four islands is 71 km² (National Statistics Bureau 2005).|
Native:Seychelles (Seychelles (main island group))
|Number of Locations:||5|
|Upper elevation limit (metres):||600|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||It has been estimated that between 2,500 and 10,000 mature individuals of M. hornei exist in the wild (RDLP workshop 2006). The exact number of mature individuals was not determined. The largest group of the species consists of about 150 individuals.
In 1899, M. hornei was described to often occur in huge numbers in damp forests and was an essential feature of the Seychelles landscape (Diels 1922). Nowadays, it is mainly found in small groups, which are mostly confined to river ravines and on slopes where is good access to water (Carlström 1996, Dogley and Matatiken 2006). Based on this clear historical comparison it is obvious, that there has been a massive population reduction in the last 100 years (during the last three generations). It is not possible to quantify this reduction, but it can be suspected that it is at least 30% in the last 100 years. Wetland clearance for cultivation may have been the main reason for this reduction.
|Current Population Trend:||Stable|
|Habitat and Ecology:||This species occurs predominantly in damp sites such as in river valleys and on slopes where there is good access to water, mostly at intermediate altitudes. From near sea level to 600 m; rarely seen below 300 m (Carlström 1996). The fruit is cone-like, resembling of pineapple, globosely, containing 80-100 drupes. The segments of the fruit are 12-13.5 cm long. The majority of the fruits fall down in the vicinity of the mother trees, leading to the present patchy distribution. Successful dispersal by fruit bats cannot be excluded and there is also a limited dispersal by rivers. Propagule exchange from one island to another can be excluded due to the weight of the fruit.|
|Major Threat(s):||The species preferred habitat type is heavily invaded by introduced species such as Paraserianthes falcataria and other invasive creepers. The species has a restricted range. Additionally the degree of isolation of the different groups may be of concern.|
|Conservation Actions:||The species is present in the Morne Seychellois National Park, Praslin National Park and Curieuse Marine National Park. Large parts of the species habitat are legally protected by the “State Land and River Reserve act” (Laws of Seychelles 1991).|
|Citation:||Ismail, S., Huber, M.J. & Mougal, J. 2011. Martellidendron hornei. The IUCN Red List of Threatened Species 2011: e.T30508A9555288. . Downloaded on 01 December 2015.|
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