The correct authority for this species has been disputed. We follow MolluscaBase (2021) which adopts the approach of Bank (2011) in considering the correct authority of this species name to be 'J. Favre, 1927' as opposed to 'Ehrmann, 1933' proposed by Welter-Schultes (2011, 2012).

Global and European regional assessment: Vulnerable (VU)
EU 27 regional assessment: Vulnerable (VU)

Although widespread, this species seems to be rare throughout its range, and many known records are old or very old and require confirmation. In some parts of its range, such as in France where available recent data is very scattered, subpopulations are so distant that geneflow between them is unlikely, and the species is considered to be severely fragmented, although this is on a precautionary basis, and further information on the viability of these fragmented subpopulations is required. Its habitat is highly threatened: wetlands are globally threatened by human activities and climate change and Euglesa pseudosphaerium does not tolerate pollution, artificial disturbance, drought or sinking of groundwater levels. A decline of 30% in the population size of this species is likely to have occurred in the past three generations, caused by habitat loss and degradation and is expected to continue in the future. The loss of suitable habitat within the last 10 years is hard to quantify but is likely significant, and threats are ongoing. Based on available data, but including older records that require confirmation, the area of occupancy (AOO) is 888 km² and is considered to certainly be less than 2,000 km². The species is therefore assessed as Vulnerable (VU A2c+3c; B2ab(iii,v) both globally and for the EU27 Member States.

This European endemic species mostly occurs in northern Europe as far north as southern Scandinavia (there are a small number of records in south-eastern Norway, including one from within a protected area, and four records for southern Sweden), but reaches south to western Ukraine and northern Italy, east to European Russia (Kaliningrad, with presence in other parts of European Russia doubtful), and west to Ireland and France (Castagnolo et al. 1980, Korniushin 1996, Falkner et al. 2001, Welter-Schultes 2012).

In England, this is a locally distributed species found principally in southern and eastern England: the Somerset Levels, the Pevensey Levels, Romney Marsh, the Kent Levels, the East Anglian Broads and marshes, and occasionally elsewhere (Kerney 1999). It also occurs in Wales, Northern Ireland and in Ireland. It is sporadically distributed in the northern and southern parts of Germany.

In the Czech Republic it was known from only two localities in 1976, but by 1996 it was recorded only at one site. However, Beran (2016) found it in 17 sites, most of them found in the last 15–20 years. Most of the sites are located in the most valuable areas which are now strictly protected (e.g. national nature reserves, national nature monuments) or at least within protected landscape areas.

In France, there is little data scattered mostly in the northern half of the country. Despite extensive eDNA surveys, the species has been recorded only twice using this method (Prié et al. 2023). In Poland, there are 30–40 localities across the country, but some require confirmation. There are ten recent confirmed records from the last decade in Belarus.

Based on available data, but including older records that require confirmation, the AOO is 888 km², and considered to certainly be less than 2,000 km².

Its range in Moldova, Switzerland,  Slovenia, Belgium, Kaliningrad, Estonia, Luxembourg and Latvia is not mapped as there is a lack of precise data.

There are no comprehensive data about the population available. Many of the known locality records are very old and require confirmation. A significant population decline is suspected based on the loss and sensitivity of the specific habitats that this species requires. The decline is not known, but a precautionary estimate of a 20–30% decline over the past ten years is used here.

In France there are many old locality records, but there has been little survey effort to revisit these old sites. Despite extensive eDNA sampling (over 400 sites between 2016 and 2022), the species has been detected only twice. These results suggest a drastic decline in France.

In Great Britain, there have been a significant number of new records in the years 2000–2010 as a result of detailed surveys of grazing marsh complexes particularly for other Biodiversity Action Plan (BAP) molluscs (Kerney 1999). There is sufficient evidence to indicate that, at present, the species may be increasing within its current range in England which supports the preferred habitat, although not necessarily outside this range (I. Killeen pers. comm.).

The species occurs mostly in shallow waters. It is a lowland species that in England 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. It does not tolerate pollution, artificial disturbance, drought and falling of groundwater levels (Welter-Schultes 2012). Its habitat is therefore rare and threatened by human activities and climate change.

The species is threatened by land drainage and pollution, eutrophication, water abstraction, changes in agricultural practice, the destruction and infilling of pools, and so on. Climate-change driven droughts will further decrease habitat quality and availability in the future.

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 this and other mollusc species which require these habitats. The future prospects are possibly good if water quality improves under the Water Framework Directive, but some decline is likely due to the loss of habitat as a result of watercourse management.

This species is not utilised.

In Germany and Austria the species is listed as Critically Endangered. In France, the species has also been assessed as Endangered based on limited AOO (IUCN French Committee 2021). In Norway, the species is listed as Near Threatened (Artsdatabanken 2021) based on limited distribution and impacts of agriculture and logging. In Slovakia, the species is listed as Critically Endangered (CR) (Nagel et al. 2006), as in the Czechia (Beran et al. 2005), where there is protection of the one site where the species is still known to be present.

Measures that could benefit this species include managing and protecting the habitat it occurs in, as well as undertaking further research into its population and habitat trends and the threats it faces. Legislation could be put in place to protect this species further.