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Pisidium pseudosphaerium 

Scope: Global
Language: English
Status_ne_offStatus_dd_offStatus_lc_onStatus_nt_offStatus_vu_offStatus_en_offStatus_cr_offStatus_ew_offStatus_ex_off

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Bivalvia Veneroida Sphaeriidae

Scientific Name: Pisidium pseudosphaerium J. Favre, 1927

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2011
Date Assessed: 2009-12-31
Assessor(s): Killeen, I.
Reviewer(s): Aldridge, D., Seddon, M.B., von Proschwitz, T., Vavrova, L. & Ward, J.
Justification:
Although sometimes locally rare, the widespread distribution of this species and the lack of significant threats means that it is classified as Least Concern (LC).

This species has also been assessed at the regional level as:
EU27 regional assessment: Least Concern (LC) at the level of the 27 member states of the European Union.
European regional assessment: Least Concern (LC).

Geographic Range [top]

Range Description:This is a European species, mostly occurring in northern Europe as far north as southern Scandinavia and stretching to Ukraine, Ireland and Italy (Castagnolo et al. 1980, Falkner et al. 2001, Korniushin 1996). In the Czech Republic it is known from only two localities (in 1976), but in 1996 it was recorded only at one site. It is sporadically distributed in the northern and southern parts of Germany. In the United Kingdom this is a locally distributed species found principally in southern and eastern England: the Somerset Levels, Pevensey Levels, Romney Marsh, Kent Levels, East Anglian Broads and Marshes, and occasionally elsewhere (Kerney 1999).
Countries occurrence:
Native:
Austria; Bulgaria; Czech Republic; Denmark; Finland; France (France (mainland)); Germany; Hungary; Ireland; Italy (Italy (mainland)); Netherlands; Norway; Poland; Slovakia; Sweden; Switzerland; Ukraine; United Kingdom (Great Britain, Northern Ireland)
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:There is no comprehensive data about population available. In the U.K there have been a significant number of new records in the past 10 years as a result of detailed surveys of grazing marsh complexes particularly for other Biodiversity Action Plan (BAP) molluscs (e.g. Segmentina nitida, Anisus vorticulus) (Kerney 1999). There is sufficient evidence to indicate that, at present, the species may be increasing within its current range which supports the preferred habitat, although not necessarily outside this range.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:The species occurs mostly in shallow waters. It is a lowland species that is sometimes a common component in drains and ditches on grazing marsh complexes but is found occasionally in larger drains and ponds. It occurs in richly vegetated, swampy habitats with clean, standing water and a muddy substrate.
Systems:Freshwater
Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):2

Use and Trade [top]

Use and Trade: This species is not utilized.

Threats [top]

Major Threat(s): The species is threatened by land drainage and pollution, eutrophication, water abstraction, changes in agricultural practice, destruction and infilling of pools, and so on. 
In the U.K the richly vegetated swampy drainage ditch habitat that the species is found in is the sort of habitat that is particularly subject to dredging and clearing often for conservation of other invertebrates which may not necessarily be appropriate for P. pseudosphaerium and other molluscs which require these habitats. The future prospects are possibly good if water quality improves under the Water Framework Directive, but some decline is likely through the loss of habitat as a result of water course management.

Conservation Actions [top]

Conservation Actions: In the U.K it is proposed as Near Threatened (NT). The future prospects are possibly good if water quality improves under the Water Framework Directive, but some decline is likely through the loss of habitat as a result of water course management.
In Slovakia the species is listed as Critically Endangered (CR) (Nagel et al. 2006), as in the Czech Republic (Beran et al. 2005), where there is protection of the one site where the species is still known to be present. There is likely to be species introduction to suitable sites in the future in this country.

Although sometimes locally rare, this species has a widespread distribution and no conservation actions are required on a species scale at present.

Citation: Killeen, I. 2011. Pisidium pseudosphaerium. The IUCN Red List of Threatened Species 2011: e.T155821A4849042. . Downloaded on 22 September 2017.
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