Ash-black Slug
CRCritically Endangered

Ash-black Slug

Limax cinereoniger

The Ash-black Slug (Limax cinereoniger) is one of Europe's largest terrestrial gastropods, reaching lengths of up to 20 centimeters. This distinctive mollusk is characterized by its dark gray to black coloration and prominent keel running along its back.

Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Limax_cinereoniger

01Classification

Taxonomy & Classification

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Stylommatophora

Family

Limacidae

Genus

Limax

Ash-black Slug belongs to the family Limacidae, order Stylommatophora, within the Gastropoda class.

02Description

Species Profile

The Ash-black Slug (Limax cinereoniger) is one of Europe's largest terrestrial gastropods, reaching lengths of up to 20 centimeters. This distinctive mollusk is characterized by its dark gray to black coloration and prominent keel running along its back. Historically distributed across parts of central and western Europe, the species has experienced severe population declines and range contractions over recent decades. The Ash-black Slug inhabits mature deciduous and mixed forests, particularly favoring beech and oak woodlands with rich leaf litter and high humidity levels. It requires undisturbed forest environments with stable microclimatic conditions and abundant organic matter for feeding. The species faces multiple threats that have contributed to its critically endangered status. Habitat destruction and fragmentation through deforestation, urban development, and intensive forestry practices have eliminated much of its suitable habitat. Climate change poses additional challenges by altering temperature and moisture regimes essential for the species' survival. Air pollution, particularly acid rain, has degraded forest ecosystems and may directly impact slug populations. The species' limited dispersal ability and specific habitat requirements make it particularly vulnerable to environmental changes. Conservation efforts focus on protecting remaining old-growth forest habitats and implementing sustainable forest management practices. Some European countries have established monitoring programs to track remaining populations, though comprehensive surveys remain limited. Habitat restoration projects in former range areas show promise, but recovery efforts are complicated by the species' slow reproduction rate and sensitivity to environmental disturbance.

The Ash-black Slug faces severe threats from habitat destruction through deforestation and urban development, which has fragmented and eliminated much of its required old-growth forest habitat. Climate change and air pollution further degrade the stable, humid forest conditions essential for the species' survival.

Key Facts

IUCN StatusCritically Endangered (CR)
GroupMolluscs
03Habitat

Habitat & Distribution

The species inhabits mature deciduous and mixed forests, particularly beech and oak woodlands with rich leaf litter layers. It requires undisturbed forest environments with high humidity, stable temperatures, and abundant organic matter.

TERRESTRIALMajor
04Threats

Threats

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IUCN Red List: Critically Endangered

The Ash-black Slug faces severe threats from habitat destruction through deforestation and urban development, which has fragmented and eliminated much of its required old-growth forest habitat. Climate change and air pollution further degrade the stable, humid forest conditions essential for the species' survival.

Detailed threat classification data is sourced from IUCN assessments as they become available.

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
EULCLeast ConcernCRCritically EndangeredLower local risk
EULCLeast ConcernCRCritically 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). Ash-black Slug (Limax cinereoniger). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/ash-black-slug

Full citation guide & data usage terms