The ramshorn snail, Anisus vorticulus is a species of minute, air-breathing, freshwater snail

Freshwater snail

A freshwater snail is one kind of freshwater mollusc, the other kind being freshwater clams and mussels, i.e. freshwater bivalves. Specifically a freshwater snail is a gastropod that lives in a watery non-marine habitat. The majority of freshwater gastropods have a shell, with very few exceptions....

, an aquatic

Aquatic animal

An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...

 gastropod mollusk in the family Planorbidae, the ramshorn snails.

Distribution

This species is mentioned in annexes II and IV of the Habitats Directive.

It occurs in:

• Czech Republic - critically endangered (CR). It's Conservation status in 2004-2006 is bad (U2) in report for European commission
  European Commission
  The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
  
   in accordance with Habitats Directive.
• England - vulnerable (VU), listed in List of endangered species in the British Isles
• Ireland
• Germany - critically endangered (vom Aussterben bedroht)
• Netherlands
• Poland
• Slovakia
• Latvia
• Croatia - in the Krka National Park
  Krka National Park
  Krka National Park is one of the Croatian national parks, named after the river Krka that it encloses. It is located along the middle-lower course of the Krka River in central Dalmatia, in Šibenik-Knin county, downstream Miljevci area, and just a few kilometers northeast of the city of Šibenik...
  
  . First finding of this species in Craoatia was in 2009.

Habitat

This small snail lives in pools with standing water and in oxbow lake

Oxbow lake

An oxbow lake is a U-shaped body of water formed when a wide meander from the main stem of a river is cut off to create a lake. This landform is called an oxbow lake for the distinctive curved shape, named after part of a yoke for oxen. In Australia, an oxbow lake is called a billabong, derived...

s, but these biotopes are threatened because of sedimentation

Sedimentation

Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained, and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration...

 and ecological succession

Ecological succession

Ecological succession, is the phenomenon or process by which a community progressively transforms itself until a stable community is formed. It is a fundamental concept in ecology, and refers to more or less predictable and orderly changes in the composition or structure of an ecological community...

.

In the Czech Republic this species usually lives in biotopes where there are lots of Lemna trisulca

Lemna trisulca

Lemna trisulca L. is a species of aquatic plants in the genus Lemna with a subcosmopolitan distribution, occurring in quiet freshwater habitats in cool temperate regions. L. trisulca normally doesn't occur in warm temperate regions...

.

Water quality

Water quality

Water quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which...

 that is suitable for Anisus vorticulus is water without turbidity

Turbidity

Turbidity is the cloudiness or haziness of a fluid caused by individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality....

; with a pH from 7 to 7,5; with calcium from 40 to 400 mg/l and with electrical conductivity from 200 to 1100 mS/m.

External links

• distribution of Anisus vorticulus at European Environment Agency
  European Environment Agency
  European Environment Agency is an agency of the European Union. Its task is to provide sound, independent information on the environment. It is a major information source for those involved in developing, adopting, implementing and evaluating environmental policy, and also the general public...
  
  webpage Anisus vorticulus and its distribution in the Czech Republic with map