CRCritically Endangered

Acaulon mediterraneum

Local name: hårsvøpmose

Acaulon mediterraneum is a tiny acrocarpous moss species characterized by its extremely small size, lack of a visible stem (acaulescent growth form), and distinctive spore capsules that remain embedded within the leaf rosettes. This diminutive bryophyte plays a crucial role in soil stabilization and microhabitat creation in Mediterranean ecosystems, forming part of the cryptobiotic crust communities that support other specialized flora.

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Countries

01Classification

Taxonomy & Classification

Kingdom

Plantae

Phylum

Bryophyta

Class

Bryopsida

Order

Pottiales

Family

Pottiaceae

Genus

Acaulon

Acaulon mediterraneum belongs to the family Pottiaceae, order Pottiales, within the Bryopsida class.

02Description

Species Profile

Acaulon mediterraneum is a tiny acrocarpous moss species characterized by its extremely small size, lack of a visible stem (acaulescent growth form), and distinctive spore capsules that remain embedded within the leaf rosettes. This diminutive bryophyte plays a crucial role in soil stabilization and microhabitat creation in Mediterranean ecosystems, forming part of the cryptobiotic crust communities that support other specialized flora.

Acaulon mediterraneum faces severe threats from habitat destruction and degradation of its specialized Mediterranean coastal environments. Urban development, agricultural expansion, and climate change are rapidly reducing the availability of suitable sandy and rocky substrates where this moss species can establish and persist.

Key Facts

IUCN StatusCritically Endangered (CR)
GroupPlants
03Habitat

Habitat & Distribution

This moss inhabits exposed calcareous soils, rocky crevices, and thin soil layers over limestone substrates in Mediterranean scrublands and open woodlands. It typically occurs on south-facing slopes and terraced landscapes where it colonizes disturbed ground and forms part of pioneer plant communities on mineral-rich, well-drained soils.

04Threats

Threats

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IUCN Red List: Critically Endangered

Acaulon mediterraneum faces severe threats from habitat destruction and degradation of its specialized Mediterranean coastal environments. Urban development, agricultural expansion, and climate change are rapidly reducing the availability of suitable sandy and rocky substrates where this moss species can establish and persist.

Agricultural intensification and land use change

HighOngoing

Climate change and altered precipitation patterns

HighOngoing

Habitat loss due to coastal development

HighOngoing

Invasive plant species competition

MediumOngoing

Trampling and recreational pressure

MediumOngoing
07National Status

National vs Global Threat Status

How this species is assessed at the national level compared to its IUCN global status (CR).

CountryNational StatusGlobal StatusComparison
EUNTNear ThreatenedCRCritically EndangeredLower local risk
EUNTNear ThreatenedCRCritically EndangeredLower local risk

National Red List data sourced from the National Red List Project (nationalredlist.org, ZSL) and country-specific Red List authorities.

Community

Community Sightings

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07Sources

Sources & Attribution

How to Cite

IUCN: IUCN (2025). The IUCN Red List of Threatened Species. Version 2025-1. Available at: https://www.iucnredlist.org. doi:10.2305/IUCN.UK.2025-1.RLTS

GBIF: GBIF.org (2025). GBIF Home Page. Available at: https://www.gbif.org

National Red Lists: ZSL (2025). National Red List. Zoological Society of London. Available at: https://www.nationalredlist.org

This page: SpeciesRadar (2025). Acaulon mediterraneum (Acaulon mediterraneum). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/harsvpmose

Full citation guide & data usage terms