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Anzia centrifuga Haugan

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Scientific name
Anzia centrifuga
Common names
IUCN Specialist Group
Assessment status
Assessment date
IUCN Red List Category
IUCN Red List Criteria
Aptroot, A., Perez-Ortega, S & Scheidegger, C.
Dahlberg, A. & Nimis, P.L.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/64081145/64081186


This species occurs only with two small subpopulations on one volcano. It is threatened by accidental extinction from trampling, grazing and possibly collecting.
Criterion A:  There are no reports about the trends of population size over long time periods, so it is not possible to apply this criterion.
Criterion B: Both B1 and B2 could be applied as the extent of occurrence (EOO) is 10 km2 and the area of occupancy (AOO) is 1 km2. However, the species does not fit the condition of also meeting two subcriteria. It only fits B1a or B2a as there is a single location. However no information is available regarding continuing declines and extreme fluctuations.
Criterion C: No information is available about the total number of individuals of this species. Thus, subcriteria C1 and C2 are not applicable. 
Criterion D: The total number of individuals is unknown but the area of occupancy (AOO) is smaller than 20 km2 and the number of locations is one. Development of tourism is a plausible threat to this species. Therefore, it qualifies for Vulnerable D2.
Criterion E: No quantitative analyses have been carried out.
The species is assessed as VU D2 until more research on the species, particularly the population size, is carried out.

Taxonomic notes

The species is easy to recognize in the field by specialist lichenologists. The species' taxonomy is well defined and it is the only species of this genus in Macaronesia. The species grows over rocks, is adnate to loosely attached to the substrate. The thallus is orbicular up to 30 cm in diameter, dying at the center of the thallus; the colour is pale grey. The thallus has numerous apothecia. Lobes are 1-2 mm wide, dichotomously branched, more or less imbricate, lobe tips showing calcium oxalate deposits. The medulla has a chondroid axis. The lower side is with a felt like layer of short rhizines characteristic of this genus. Secondary metabolites include atranorin and several unknown terpenoids.

Geographic range

This species occurs only with two small subpopulations on one volcano on Porto Santo (Madeira, Portugal).

Population and Trends

The species is restricted to one locality on a volcano. The species was found on two rock surfaces. Population size was not assessed.

Population Trend: unknown

Habitat and Ecology

Anzia centrifuga grows on well illuminated rocks together with various crustose lichens.


This species occurs only with two small subpopulations on one volcano. It could be threatened by accidental extinction from tourism, fire, trampling, grazing and possibly collecting if development of tourism occurred in the vicinity of the population. The past impact of these threats has not been documented. There is a road in to the locality and if this is not changed then the impact of these threats is likely to remain negligible. However, expansion of this road for development for tourism would result in the habitat becoming heavily disturbed and degraded. This is therefore a plausible threat to the species.

Conservation Actions

No conservation plan is available. There is an urgent need for a detailed assessment of population size, the extent of occurrence and trend.

Use and Trade

Possibly collected for scientific investigations

Source and Citation

Aptroot, A., Perez-Ortega, S & Scheidegger, C. 2014. Anzia centrifuga. The IUCN Red List of Threatened Species 2014: e.T64081145A64081186. https://dx.doi.org/10.2305/IUCN.UK.2014-3.RLTS.T64081145A64081186.en .Downloaded on 31 January 2021

Country occurrence