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Balthasaria mannii (Oliv.) Verdc. Search in The Plant ListSearch in IPNISearch in Australian Plant Name IndexSearch in NYBG Virtual HerbariumSearch in Muséum national d'Histoire naturelleSearch in Type Specimen Register of the U.S. National HerbariumSearch in Virtual Herbaria AustriaSearch in JSTOR Plant ScienceSearch in SEINetSearch in African Plants Database at Geneva Botanical GardenAfrican Plants, Senckenberg Photo GallerySearch in Flora do Brasil 2020Search in Reflora - Virtual HerbariumSearch in Living Collections Decrease font Increase font Restore font
 

Published In: Kew Bulletin 23: 469. 1969. (Kew Bull.) Name publication detail
 

Project Name Data (Last Modified On 4/14/2020)
Acceptance : Accepted
Taxon Profile     (Last Modified On 10/27/2021)
Description : Tree up to 15 m high, and 1 m in diameter.
Habitus : Tree
Habitat : Occurs in open mountain forest; between 1,600 and 2,000 m in altitude.
Distribution : São Tomé (endemic)
Distribution Note : The species is endemic to São Tomé island, and is known from six collections made between 1861 (Mann #1066) and 2019 (Lachenaud #2871) at the summit or around the Pico de São Tomé and the Pico Pequeno.
Note : The species has a very restricted population. We consider the number of mature individuals to be less than 50. Only one adult individual was found in the field in 2019.
More literature : Exell, A.W. 1959. Additions to the flora of S. Tomé and Principe. Bulletin de l’Institut Français d’Afrique Noire, série A 21(2): 439-746., Figueiredo, E. 1994. Diversity and endemism of angiosperms in the Gulf of Guinea islands. Biodiversity and Conservation 3: 785-793.
Case Study : São Tomé

Conservation assessment     (Last Modified On 10/27/2021)
Red List Category : Critically Endangered
Status of Conservation Assessment : Submitted to Red List
Date of assessment : 15 May 2021
Assessment rationale : Balthasaria mannii is a tree up to 15 m high, and 1 m in diameter; known from open mountain forest between 1,600 and 2,000 m in elevation. The species is endemic to São Tomé island and is known from six collections made between 1861 (Mann #1066) and 2019 (Lachenaud #2871) at or around the top of the Pico de São Tomé. The four other collections were made in 1907 (Campos #38, without precisely locality), and in 1956 (Monod #11922 at Western face of Pico de São Tomé, Monod #11973 at Pico Pequeno, and Monod #12228bis at Pico, western slope) (Exell 1959). Because of the inaccurate geographical information the occurrence represented by the collection Campos (#38) is not considered for this evaluation. The five collections represent four distinct occurrences. Considering the forest cover, which has not been disturbed or reduced in the area, we consider none of those occurrences as extirpated. Despite recent sampling specifically conducted to search for that species, only one mature individual was found. However, a large part of the mountain forest on the Pico de São Tomé is inaccessible because of the steep slopes. The western slopes of the Pico de São Tomé have also not been surveyed and more individuals may occur here. This species is a long-lived species with a generation time likely over 60-years. Its habitat could be directly threatened by tourist activities (e.g. accidental fires from campers), and be indirectly threatened by the expansion of invasive species. In particular, we infer native tree populations to be replaced by populations of Cinchona tree species. Cinchona sp. was largely planted at the end of the 19th century, and observations on its dynamics (locally high frequency in both upper canopy and lower strata highlighting its regeneration capacity) support the hypothesis it could be invasive and threaten native plant populations (e.g., Erica and Lobelia) in this ecosystem. This invasion has not ceased. Based on a 2 x 2 km cell size, the the area of occupancy (AOO) of this species is estimated as 8 km2, below the upper threshold for “Critically Endangered” status under subcriterion B2. The extent of occurrence (EOO) is estimated as 0.124 km2, below the AOO, so we consider the EOO as 8 km2 below the upper threshold for “Critically Endangered” status under subcriterion B1. These three occurrences represent one subpopulation. All are located within the Ôbo Natural Park (PNOST) and are threatened by Cinchona invasion that will degrade the quality of the habitat. Consequently, they represent one location (sensu IUCN 2019), with regards to the most serious current threat (invasive species). Based on the past, and current threat of the occurrences at the Pico São Tomé and at Pico Pequeno, we infer a past, present, and future continuing decline in the extent and habitat quality. In fact, we do not know how many individuals exist. We can say the occurrence documented by Lachenaud #2871 consists of a single tree, but we did not survey the west slopes of the Pico de São Tomé, where more individuals are likely to occur (based on Monod’s historical collections). Still, there is a good probability the number of individuals is < 50, so subcriteria C2 and D also apply. Therefore, we infer a continuing decline in the number of mature individuals (90% of its mature individuals). Balthasaria mannii is thus assessed as Critically Endangered (CR) B1ab(iii,v)+2ab(iii,v); C2a(i,ii); D.
Disclaimer : This assessment was prepared on 15 May 2021. The map proposed below is only based on the specimens available on Tropicos, therefore, may not correspond to the information provided in the assessment rationale.
Conservation measures : The species is threatened by Cinchona at the top of Pico de São Tomé and Pico Pequeno. Indeed, control of invasive species like Cinchona must be applied. The species should be sought in both Pico de São Tomé and Pico Pequeno where other individuals could occur, especially on the western slopes that were not visited by our expedition. This species should be regarded as an HCV1 (High Conservation Value), and as a consequence, should be included in the management plan of the Obô National Park, where it occurs. It should be included in São Tomé and Príncipe’s list of protected species, and the destruction of its habitat and possible harvesting must, therefore, be limited. Ex situ conservation should be tested, both within São Tomé and internationally. Finally, a public awareness campaign must be conducted involving tourists and other private actors, NGOs, scientific institutions, and the São Tomé and Príncipe government, to ensure that B. mannii is taken into consideration when decisions are made that could impact its conservation.

 


 

Specimens whose coordinates are enclosed in square brackets [ ] have been mapped to a standard reference mark based on political units.
 
 
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