Fan-leaved Water-crowfoot
Ranunculus circinatus
The fan-leaved water-crowfoot is a perennial aquatic plant that grows almost entirely submerged in stagnant or slow-moving waters. Its leaves are rigid and maintain their circular, wheel-like shape even when removed from the water, which is a key distinguishing feature from related species. During summer, the plant produces small white flowers with yellow centers that rise just above the water surface. It is considered an indicator species for nutrient-rich, often calcareous aquatic ecosystems.
Details
Oxygen production
Very high, as the entire submerged plant is photosynthetically active.
Habitat function
Important spawning site for fish and refuge for aquatic invertebrates.
Nutrient uptake
Effective uptake of dissolved nitrogen and phosphorus from the water column.
Food source for
Seeds and leaves are eaten by ducks; stems serve as grazing grounds for snails.
Human use
Occasional use as an oxygenating plant in garden ponds or aquariums.
Ecology
Ecological role
Provides structure in water bodies, serves as an oxygen source, and provides habitat for zooplankton and juvenile fish.
Natural predators
Waterfowl (e.g., Mute Swan), herbivorous fish (e.g., Common Rudd), and muskrats.
Competitor species
Other water-crowfoot species or invasive neophytes such as Nuttall's waterweed.
Ecosystem service
Oxygen enrichment of the water and nutrient sequestration, contributing to clear-water states in lakes.
Threats
Excessive eutrophication, herbicide input from agriculture, and mechanical cleaning of drainage ditches.
Scientific profile
Profile
Reproduction
Generative reproduction via seeds and vegetative reproduction through fragmentation of stem parts that easily take root.
Protection & threats
Main threats
Eutrophication (excessive algal growth), mechanical stress from boat traffic, river engineering, and herbicide input.