|Scientific Name:||Heberdenia excelsa (Ait.) Banks|
Ardisia bahamensis (Gaertn.) DC.
Heberdenia bahamensis (Gaertn.) Sprague
|Taxonomic Source(s):||Marhold, K. 2011. Myrsinaceae. In: Euro+Med Plantbase - the information resource for Euro-Mediterranean plant diversity. Berlin Available at: http://ww2.bgbm.org/EuroPlusMed/.|
|Red List Category & Criteria:||Vulnerable C1 ver 3.1|
|Assessor(s):||Beech, E., Fernandes, F. & da Silva Menezes de Sequeira, M.|
|Reviewer(s):||Marrero Rodríguez, Á, Medina Hijazo, F., Naranjo Suárez, J., Santana López, I., Silva, L., Peraza Zurita, M.D. & Allen, D.J.|
|Contributor(s):||Bañares Baudet, A. & Scholz, S.|
This species is a shrub or small tree found in Madeira and the Canary Islands. It is relatively widespread across its distribution, but although the population size is likely over 3,000 mature individuals, populations are fragmented and can comprise a low number of individuals. The populations in the Canary Islands are affected by browsing by rats and goats, by wildfires and by landslides. The Madeira population does not have significant threats, although they have recently been affected by wildfires.
The species is assessed as Vulnerable (VU C1), given that the population size is below 10,000 individuals and a continuing decline in the number of mature individuals of at least 10% in ten years or three generations can be estimated for the species. Given the delicate situation of the populations on El Hierro and Fuerteventura, this conservative approach is recommended.
|Range Description:||This species is endemic to the Macaronesian region, where there are records from the Canary Islands (on the islands of Fuerteventura, Gran Canaria, Tenerife, La Gomera, El Hierro and La Palma; Martín Osorio et al. 2008) and the Madeira Archipelago (on Madeira and the islands of Desertas and Porto Santo; Borges et al. 2008). The estimated extent of occurrence (EOO) is 124,000 km2 and the area of occupancy (AOO) is 304 km2. The species occurs from 200 to 1,300 m asl.|
Native:Portugal (Madeira); Spain (Canary Is.)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||On the Canary Islands, the species is found in small populations, sometimes with only a single individual. The populations on Gran Canaria and the single populations on El Hierro and Fuerteventura include very few individuals and are in decline. There are an estimated 2,053 individuals in the Canary Islands (Martín Osorio et al. 2008). In Madeira, there are fewer than 1,000 individuals (M. Sequeira pers. comm. 2016), with few seedlings seen. Population size in the Canaries is thought to have decreased over time as a result of pressures affecting the taxon. The restricted size of the populations of El Hierro and Fuerteventura support this idea.|
A continuing decline in the number of mature individuals of at least 10% in 10 years or three generations can be estimated for the species.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||This species grows a shrub or tree up to 20 m but more commonly not taller than 10 m. The majority of individuals known are shrubs in the Canary Islands. It is an uncommon species of lowland thermophilous forest, of laurisilva forest and, at higher altitudes, cloud forest, mainly in areas influenced by the trade winds (Martín Osorio et al. 2008). It is also found on rocks and on inaccessible cliffs. The plant can produce suckers, so often groups of individuals are actually a single organism (Martín Osorio et al. 2008). Whilst predominantly a higher-altitude species, in some areas (e.g., the northeastern coast of Tenerife, Los Silos, Icod, El Tanque, Buenavista, etc.) it occurs at lower elevations of 200-400 m, being a part of the so-called 'thermophilous forests' which are now reduced to small patches.|
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Generation Length (years):||30-40|
|Use and Trade:||In Madeira, the tree was used to make barrels for wine and honey, the structure of boats and inlay as the wood is very hard. The bark was used to treat leather as it contains tannin compounds. In the Canaries the fruits are traditionally used to make jam.|
|Major Threat(s):||Threats to this species include wildfires, landslides and browsing by rats. The Fuerteventura and El Hierro populations have been reported to be affected by grazing from goats. Changes to the course of waterways for human use is decreasing the available water for this species. It is also affected by natural drought. In Madeira, there is no recorded threats to this species.|
|Conservation Actions:||The species is assessed as Vulnerable in the Canary Islands and for Spain (Martín Osorio et al. 2009). This species was assessed globally as Vulnerable (Oldfield et al. 1998). The species is found within the National Park of Garajonay and the Rural Park of Anaga amongst others. It is also protected by law. The suggested conservation actions include specific monitoring for the Fuerteventura population and education and awareness. Care must also be taken when clearing old pathways as many of the small populations are close to public access trails (Martín Osorio et al. 2008). It is in the Madeira Natural Park, Natura 2000 sites and the World Heritage Site. Heberdenia excelsa is reported as held in six ex situ collections (BGCI 2015).|
|Citation:||Beech, E., Fernandes, F. & da Silva Menezes de Sequeira, M. 2017. Heberdenia excelsa. The IUCN Red List of Threatened Species 2017: e.T37669A80566415.Downloaded on 14 December 2017.|