Common Stonewort vs Polar bear

Chara vulgaris compared with Ursus maritimus

Key Differences

Common Stonewort is Endangered while Polar bear is Vulnerable.

Taxonomic Classification

Rank	Common Stonewort	Polar bear
Kingdom	Plantae (植物)	Animalia (動物)
Phylum	Charophyta (車軸藻植物門)	Chordata (脊索動物)
Class	Charophyceae (車軸藻綱)	Mammalia (哺乳類)
Order	Charales (車軸藻類)	Carnivora (ネコ目)
Family	Characeae	Ursidae (Bears)
Genus	Chara	Ursus (Bears)
Species	Chara vulgaris	Ursus maritimus

Conservation Status

Common Stonewort

EN — Endangered

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

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

Habitat & Geographic Range

Common Stonewort

Habitat

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

Range

Widely distributed across Asia (Taiwan), Europe (Denmark, Norway, Sweden), North America (United States), and South America (Brazil). Currently classified as Endangered 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.

Common Stonewort

Chara vulgaris, the common stonewort, is a species of charophyte green alga in the family Characeae, order Charales. It typically grows submerged in freshwater habitats including ponds, lakes, ditches, and slow-moving streams, often forming dense mats on the substrate. The species has a broad geographic distribution spanning Asia, Europe, and the Americas, tolerating a range of water conditions from clear to moderately turbid. Chara vulgaris is notable for its heavily calcified, whorled structure that gives stoneworts their characteristic encrusted appearance and makes them valuable as paleoclimate indicators in sediment records. As a primary producer, it contributes to aquatic food webs and provides habitat for invertebrates and juvenile fish. Biological traits such as individual lifespan, precise growth rates, and specific consumer relationships remain poorly documented in the literature. Despite its wide range, Chara vulgaris is assessed as Endangered by the IUCN, reflecting significant population declines attributed to freshwater pollution, eutrophication, and habitat degradation across much of its range. Targeted conservation of clean, oligotrophic water bodies is essential for its persistence.

Polar bear

地球上で最大の陸上肉食動物であるホッキョクグマは700kgを超えることがあり、カナダからロシアまでの北極海氷域全体に分布する。ワモンアザラシとヒゲアザラシを狩るために海氷に依存する高度に特化した海洋哺乳類である。広大な距離を泳ぐことができる優れた泳者でもある。脆弱種に指定されており、気候変動による急激な北極海氷の消失で個体群が深刻な圧力を受けている。