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Niebla ramosissima Spjut

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Scientific name
Niebla ramosissima
Common names
IUCN Specialist Group
Assessment status
Assessment date
IUCN Red List Category
IUCN Red List Criteria
Reese Næsborg, R.
Dal Forno, M.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/175709793/175710677


Niebla ramosissima is narrowly endemic to San Nicolas Island where it is known from one location and its Area of Occupancy = 16 km(up to a maximum of 32 km2). The main threats that could rapidly drive this species from Vulnerable to Critically Endangered or Extinct would be if invasive species and climate change transformed its natural habitat, the sea-side low-shrub vegetation with a predominance of soil crusts in Mediterranean California. Therefore, it is listed as Vulnerable, D2.

Geographic range

This species is a narrow endemic of San Nicolas Island, California. All observations are from the south/south-east end of the island, but it could have a slightly wider distribution on the island.

Population and Trends

The species is common on San Nicolas Island, where it can dominate large patches of soil on the south/south-east end of the island. Currently, it appears to be stable.

Population Trend: stable

Habitat and Ecology

Niebla ramosissima is a terricolous species growing on calcareous soil rich in gypsum. It is an asexual, clonal species spreading by fragmentation. Wind or erosion easily break off branches of the thallus which then form a new individual. The south/south-eastern part of the island where the lichen occurs is dominated by canyons. The vegetation consists mainly of low-growing sub-shrubs and herbs, but the majority of the ground cover consists of soil-crusts. San Nicolas has a semi-arid climate with Mediterranean characteristics. Although the island only receives around 200 mm precipitation a year, dense fog is a common phenomenon.


Several invasive plants (e.g. Mesobryanthemum spp.) have established on the island, and could pose a threat in the future. Climate change could affect the species through decreased fog regime and potentially through sea level rise.

Conservation Actions

The island is owned by the United States Navy and it is not open to the general public. Some areas of the island, including areas where the species occurs, are off limits to most Navy personnel. The species is currently not protected. Federal protection would require the Navy to take protective actions. The species would greatly benefit from removal of invasive plants such as Mesobryanthemum, which tends to dominate areas where it establishes. This may prove to be extremely difficult because of the very rugged terrain on the island. Research into its full population size and distribution would also be beneficial, if logistically possible.

Source and Citation

Reese Næsborg, R. 2020. Niebla ramosissima. The IUCN Red List of Threatened Species 2020: e.T175709793A175710677. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T175709793A175710677.en .Accessed on 15 February 2024

Country occurrence