Ciliate Crystalwort vs Polar bear

Riccia crozalsii compared with Ursus maritimus

Taxonomic Classification

Rank	Ciliate Crystalwort	Polar bear
Kingdom	Plantae (植物)	Animalia (动物界)
Phylum	Marchantiophyta (地钱门)	Chordata (脊索动物门)
Class	Marchantiopsida (地钱纲)	Mammalia (哺乳動物)
Order	Marchantiales (地钱目)	Carnivora (食肉目)
Family	Ricciaceae	Ursidae (Bears)
Genus	Riccia	Ursus (Bears)
Species	Riccia crozalsii	Ursus maritimus

Conservation Status

Ciliate Crystalwort

VU — Vulnerable

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

Attribute	Ciliate Crystalwort	Polar bear
Diet	—	Carnivore
Average Lifespan	—	25 years
Average Length	—	2.4 m
Average Weight	—	450.0 kg

Habitat & Geographic Range

Ciliate Crystalwort

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Belgium, Luxembourg, Norway, and Portugal. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Polar bear

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and boreal forests and taiga, among 4 distinct biome types within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found in Norway. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Ciliate Crystalwort

Ciliate crystalwort (Riccia crozalsii) is a thalloid liverwort in the family Ricciaceae, classified as Vulnerable in Europe. It grows as a flat, strap-like or rosette-forming thallus, typically in damp, disturbed or ephemeral habitats such as the margins of seasonal pools, rutted tracks, and temporarily flooded ground with sparse vegetation cover. The species is characterized by thallus margins fringed with fine cilia-like teeth, which give it its common name. Riccia crozalsii is found in Mediterranean and Atlantic regions of Europe, with records from Spain, Portugal, France, Italy, and parts of the British Isles, though populations are generally sparse and localized. It tends to appear in winter and spring when suitable wet conditions prevail, and the thallus desiccates or disappears during dry summer months. The species is assessed as Vulnerable due to the loss and degradation of its specialized ephemeral wetland habitats, driven by drainage, agricultural intensification, and altered hydrological regimes across Europe. As with many liverworts dependent on wet, open habitats, Riccia crozalsii has experienced declines in regions where traditional low-intensity land management practices have been abandoned. Monitoring and protection of ephemeral pool and wetland margins are key conservation actions for this species.