The Natrix natrix complex has long been treated as a single widespread species throughout Europe and temperate Asia. Numerous subspecies have traditionally been recognized; recent molecular evidence indicates that most of these are not supported genetically (Speybroeck et al. 2016) but that the grass snake forms three geographically discrete clusters, each of which has recently been recognized as distinct species: Natrix astreptophora (Iberia) (Porkrant et al. 2016), N. helvetica (northern and central Europe) (Kindler et al. 2017) and N. natrix.

Kindler and Fritz (2018) "tentatively" elected to recognise five traditional subspecies within N. helvetica on the basis of molecular and morphological data: N. h. cetti, N. h. corsa, N. h. lanzai and N. h. sicula in addition to the nominate form. These authors acknowledge that N. h. cetti and N. h. corsa are not "unambiguously" distinct, and are indeed likely to represent the same form, but recommend retaining them as distinct for conservation purposes as both are recognized as being rare and at risk. Microsatellite data suggest that N. h. cetti is not distinct from N. h. corsa (Schultze et al. 2020), but this was based on a small sample size and Fritz and Schmidtler (2020) advise the collection of more data before formally synonymising N. h. corsa within N. h. cetti as this may have negative implications for the conservation of the Sardinian population. These authors also synonymized N. h. lanzai within N. h. siculus.

Global and European regional assessment: Least Concern (LC)
EU 27 regional assessment: Least Concern (LC)

The European Grass Snake is endemic to Europe. The species is assessed as Least Concern in both Europe and the EU 27 Member States (which encompasses the majority of the species' global range) on the basis that this species is abundant and widespread, although it is undergoing recognised declines in parts of its distribution.

This species is endemic to Europe, where it ranges from southwestern mainland France and Corsica, east to western Germany, south to Italy (including Sardinia and Sicily) and north to Great Britain, where it occurs in most of England and Wales but is absent from Scotland (Kindler et al. 2017). It occurs in Slovenia and the Istria region of northern Croatia (Geniez 2018). This species co-occurs with the Iberian Grass Snake Natrix aspreptophora in mainland France.

It is a common species but with fragmented subpopulations through parts of its range. The subspecies recognised from Sardinia and Corsica are all very localised. Restoration of habitat in non-protected areas of the Netherlands since ca. 1985, including creating habitat such as ditches for the Common Frog, a common prey species, has resulted in significant increases of both European Grass Snake and Common Frog subpopulations since around 2000 (C.C. De Haan pers. comm.).

This snake is typically found in damp places, such as wet meadows, around standing water and along the banks of streams. It is sometimes found a long way from any standing water and can often be found in wooded localities and in heathland. It is tolerant of heavily-modified lansdcapes where suitable watersources are present, and can live in domestic gardens and urban parkland. This species swims well and typically forages on fish and amphibians. It also eats young birds and small mammals. Larger females may lay up to 100 eggs (but usually fewer) during June and July (Speybroeck et al. 2016). Young females lay about 10 eggs (Spellerberg 2002).

It is locally impacted in parts of its range by water pollution impacting prey populations (principally amphibians), drainage of wetland habitats (in Switzerland 90% of wetland habitats have been drained [A. Meyer pers. comm.]) and general intensification of agricultural methods. Two subpopulations - described as the subspecies Natrix helvetica cetti (Sardinia) and N. h. corsa (Corsica) - are considered to be threatened with extinction. As with many snakes this species is generally persecuted by people. The species appears to have strongly declined in Belgium (considered there as Vulnerable), a decline that may be linked to a rapid expansion of wild boar populations in this country (Graitson et al. 2018). Santos et al. (2022) detected a moderate decrease for the N. natrix complex in Spain (-23.3% over three generations) and in Southern France (-25.3%). In Germany wetland clearance over the past century is considered to have led to significant declines in the two grass snake species in this country, although subpopulations may now be stable or increasing in areas where this pressure has slowed or wetland restoration has taken place (Rote-Liste-Gremium Amphibien und Reptilien 2020). In Switzerland, a reduction of 37.5% over three generations was observation (OFEV and info fauna, 2023). This reduction follows a previous reduction of 43% (evaluated on random square kilometers) observed during the previous red list (Monney and Meyer, 2005).

There appears to be no substantial use of this species.

Natrix natrix, encompassing the older concept of this species that included populations now referred to N. helvetica, is listed on Annex III of the Bern Convention. As subspecies of Natrix natrix, N. h cetti and N. h. corsa are listed on Annex IV of the European Union Habitat and Species Directive. It is protected by national legislation in some range countries. It is present in many protected areas throughout its range.

The construction of corridors underneath roads could aid in significantly reducing mortality on roads for some subpopulations (J.M. Pleguezuelos pers. comm. 2008). N. helvetica (as a subspecies of N. natrix) is categorised as Vulnerable in Switzerland (Monney and Meyer 2005). Wetland restoration is recommended to increase habitat connectivity and benefit amphibian prey populations (Rote-Liste-Gremium Amphibien und Reptilien 2020). In the UK, it is illegal to sell or harm this species.