The European population has been regarded by some authors as a distinct subspecies (Kiauta and Kiauta 1991, Lohmann 1992), but subsequent studies have shown that there is no evidence for this.

European regional assessment: Vulnerable (VU)
EU 27 regional assessment: Endangered (EN)

The Siberian Bluet (Coenagrion hylas) is one of the rarest damselflies in Europe, with only few and often small known subpopulations. It has three clusters of populations, two in Northern European Russia and one in Austria, with a former locality in Germany, close to those in Austria, now extinct. As a result of intensive research in the Austrian Tirol (the Lech River valley), the whole area inhabited by this species in Central Europe has proved to be small (presently <14 reproducing localities over an extent of occurrence (EOO) of about 175 km² and an area of occupancy (AOO) of 16 km²). The situation in Russia is poorly known, but the species is also very local there, however there are likely to be more populations in northern European Russia which would increase the AOO and number of locations. Drought periods in connection to climate change may seriously alter available habitats (desiccation of shallow pools). It is estimated that the population does not exceed 2300 mature individuals with a projected decline of 10% in 10 years (Lamdmann and Landmann, in press) therefore the species is classified as Vulnerable under criterion C1 at the European level. In Europe, it is also assessed as Vulnerable under criterion D2 due to its restricted range and plausible threat of climate change. This species is an ice-age relic and is very sensitive to climate change which could cause further rapid declines in the population.

The Austrian population is declining, estimated to be more than 20% in 5 years (Landmann and Landmann, in press), and has a very limited distribution and number of individuals. Furthermore, these populations are not independent and exist as fewer than five threat-defined locations as most, if not all, can be affected by a single threat such as a local drought. Therefore the population in EU 27 is considered to be Endangered (B2ab(v); C1).

In the European region, the species is known from a small number of disjunct known extant subpopulations. Two are in North European Russia; one occurs in the surroundings of the northern Urals (the Ob River delta), with some records in Europe, and the second occurs in Archangelsk Oblast. The thirds European subpopulation is located in the Austrian Tirol (mainly in the valley of the Lech River) (Müller 2000, Kosterin 2005, Landmann et al. 2005, Raab et al. 2006, Boudot et al. 2015). The former single German subpopulation (lake Zwingsee near Inzell, Bavaria) is now extinct due to habitat management and fish farming. The fragmented area of the species is attributed to post-glacial climate oscillations, the species having immigrated towards the west of Europe during the Atlantic period - post-glacial climatic optimum. Subsequent climate cooling coupled to high habitat specialisation led to the fragmentation of the primary range of the species over large areas. In the Tyrol there are several subpopulations within a total area of 42 km² (Landmann et al. 2021).

At the global scale, this is a species with a disjunct range. A very large and continuous population occurs from Siberia to Japan, but there are several disjunct subpopulations.

This species is assuredly one of the rarest Odonata in Europe (Boudot et al. 2015) and the current population trends in both Austria and Russia are poorly known, but the overall trend is inferred to be declining with a continuing decline in the number of mature individuals, based on the studies situation in Austria.

In Austria, the species is known from 14 reproducing localities, but the known subpopulations show very contrasting densities both between sites and between years. Some localities show about 800 to 5,000 exuviae per year, depending on the year. In 2019 the whole Austrian population was assessed as having 1,153 (±163) males based on mark-recapture studies (Landmann 2021). The Austrian population is estimated to have declined by more than 20% in five years (Landmann and Landmann, in press). For Austria, the conservation status was assessed as unfavourable (Rabitsch et al. 2020).

In Europe, the species is confined to shallow and more or less peaty pools and small lakes with clear oligotrophic water and zones of slow shallow running and seepage water. The Russian subpopulations, and subpopulations at higher elevations in the Alps, occur in bog habitats (Landmann and Landmann, in press). In Austria it occurs in different habitat types at lower elevations, clear lakes but also small shallow spring creeks with stands of sedges. The inflow of cold underground seeping water seems to be imperative (Landmann and Landmann, in press).

At the moment, the populations are stable and the species is not severely threatened. Potential future threats include water pollution, changes of habitat structure and water regime, eutrophication, introduction of fishes, climate change and collection even at low rates by entomologists. Drought periods and increasing water temperature in relation to climate change may lead to a serious decrease of the species in Europe.

There is no trade or use of this species.

Precautionary conservation measures are needed such as control of water pollution and water regime, and restoration of some water bodies as well as restricted capture by entomologists, except for true scientific research, with control of localities by officers. C. hylas (ssp. C. hylas freyi) is listed in Annex II of the EC Habitats Directive and is included in Annex II of the Bern Convention. The Austrian localities are included in a Natura 2000 area and in the subsequent "Tiroler Lech" Naturpark.