Floating Hook-moss
EN

Floating Hook-moss

Warnstorfia fluitans

UnknownLCEULCEU

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

Overview

A detailed profile for this species is sourced from the IUCN Red List of Threatened Species as assessments become available.

Floating Hook-moss depends on stable water chemistry and consistent hydrology within acidic bogs, fens, and pool systems, making it highly sensitive to peatland drainage and water table drawdown for agriculture and forestry. Nutrient enrichment from agricultural runoff and atmospheric nitrogen deposition alters the low-nutrient conditions this species requires, favoring competitive vascular plants over sensitive bryophytes. Peat extraction for horticultural and fuel use has directly destroyed occupied wetland habitat across parts of its range, while shifting precipitation patterns linked to climate change threaten the water-saturated microhabitats it colonizes.

Threat summary

Habitat

This aquatic-to-semiaquatic moss forms floating or submerged mats in nutrient-poor, acidic bog pools, fens, and slow-moving peatland waters, typically rooting in saturated Sphagnum-dominated substrates.

Other threatened species in Calliergonaceae

Heart-leaved Spear-mossVU

Heart-leaved Spear-moss

Calliergon cordifolium

Unknown
VU

spring hook moss

Warnstorfia pseudostraminea

Unknown
Giant Spear-mossVU

Giant Spear-moss

Calliergon giganteum

Unknown
VU

Calliergon megalophyllum

Unknown

Threatened in Åland Islands

Scarce BlackneckCR

Scarce Blackneck

Lygephila craccae

Unknown
EN

Dolichopus notatus

Unknown
Haplodrassus cognatusCR

Haplodrassus cognatus

Unknown
Yellow-breasted BuntingCR

Yellow-breasted Bunting

Emberiza aureola

Declining

Frequently asked questions

Why is Floating Hook-moss classified as Endangered?
Floating Hook-moss is classified as Endangered — facing a very high risk of extinction in the wild — because population numbers are declining steeply and key habitats are under sustained pressure. Floating Hook-moss depends on stable water chemistry and consistent hydrology within acidic bogs, fens, and pool systems, making it highly sensitive to peatland drainage and water table drawdown for agriculture and forestry. Nutrient enrichment from agricultural runoff and atmospheric nitrogen deposition alters the low-nutrient conditions this species requires, favoring competitive vascular plants over sensitive bryophytes. Peat extraction for horticultural and fuel use has directly destroyed occupied wetland habitat across parts of its range, while shifting precipitation patterns linked to climate change threaten the water-saturated microhabitats it colonizes.
Where does Floating Hook-moss live?
Floating Hook-moss occurs in Åland Islands, Andorra, Argentina, Armenia, Australia, and Austria (plus 55 other countries). Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Floating Hook-moss?
The main threats to Floating Hook-moss are ai-1, ai-2, ai-3, and ai-4. The full IUCN-classified threat record for this species is detailed on the species page.

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