vs small tortoiseshell

Cliostomum leprosum compared with Aglais urticae

Key Differences

is Vulnerable while small tortoiseshell is Near Threatened.

Taxonomic Classification

Rank		small tortoiseshell
Kingdom	Fungi (Fungi)	Animalia (Animals)
Phylum	Ascomycota (Sac Fungi)	Arthropoda (Arthropods)
Class	Lecanoromycetes (Lecanoromycetes)	Insecta (Insects)
Order	Lecanorales (Lecanorales)	Lepidoptera (Butterflies & Moths)
Family	Ramalinaceae	Nymphalidae (Brush-footed Butterflies)
Genus	Cliostomum	Aglais
Species	Cliostomum leprosum	Aglais urticae

Conservation Status

VU — Vulnerable

small tortoiseshell

NT — Near Threatened

Physical Characteristics

Attribute		small tortoiseshell
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Habitat

Native to Europe and North America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Norway, Sweden, and United States. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

small tortoiseshell

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Found across Europe (41 countries). Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

Cliostomum leprosum is a crustose lichen-forming fungus in the family Ramalinaceae, notable for its powdery, leprose thallus that gives it a granular, mealy appearance on bark and wood substrates. Unlike many lichens that form well-defined, structured thalli, C. leprosum produces a loosely coherent sorediose crust ranging from pale greenish-grey to whitish, often colonizing deeply shaded, moist bark on deciduous and coniferous trees. The species is distributed across boreal and temperate forests of Europe and North America, with confirmed records from Norway, Sweden, and scattered locations in the United States. It photosynthesizes in partnership with green algal partners typical of crustose lichens. Cliostomum leprosum is assessed as Vulnerable due to its sensitivity to air pollution, particularly sulfur dioxide and nitrogen compounds that degrade lichen communities. Its decline is linked to habitat loss from intensive forestry, removal of veteran trees, and acidic deposition. Conservation efforts focus on preserving old-growth and semi-natural forest stands that provide suitable, low-disturbance bark microhabitats where this inconspicuous but ecologically significant lichen can persist.

small tortoiseshell

small tortoiseshell (Aglais urticae) is classified as Near Threatened (NT) on the IUCN Red List. Close to qualifying as threatened, with populations that may become vulnerable without conservation action.