The Baltic populations were formerly regarded as a distinct taxon, namely A. osiliensis or A. serrata osiliensis Mierzejewski, 1913. The characters separating these two taxa are however weak and are now considered insignificant, reflecting at most more genetic variability than true speciation. Here A. osiliensis is regarded as a synonym of A. serrata.

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

We know very little about the occurrence of Aeshna serrata in most of European Russia and the habitat of the species along the Baltic Sea, but in most of its European range, it appears to be either fairly stable or expanding, and there is currently no reason to believe it is under any threat. The species is therefore assessed as Least Concern.

A. serrata has a large continuous distribution between the Ural Mountains and Lake Baikal. Outside of this, it is known from fairly isolated areas as far east as Kamchatka and southeast of the Black Sea. In Europe, it is limited to the north-eastern part where it has a scattered distribution in a narrow belt from the European part of Russia in the northeast through Estonia, Finland, and Sweden to Jutland in Denmark in the west. Unverified information is also available from Norway and Ukraine (unmapepd). Whether the species’ more isolated occurrences are connected is currently unknown. During the 21st century, it has been found both west and south of the previous range in Sweden and it has colonised Denmark. In Sweden, it is verified that it at least partly has expanded. For some new sites and for those in Denmark, however, it is unclear whether they consist of newly established populations or whether the species was previously overlooked. It has also been found in new areas in the European part of Russia and it is possible that it is more common there than we know today (Billqvist et al. 2019, Kalkman and Karjalainen 2015).

A. serrata is common around the Urals and under no threat there (Kalkman and Karjalainen 2015, Yanybaeva et al. 2006). During the last twenty years, it has been discovered in the northern part of European Russia, in the Arkhangelsk province (Bernard and Daraz 2010), as well as in additional Swedish regions. In Sweden, it has established itself isolated well away from the main distribution area, which also was the case in Denmark, where it was found in Jutland in 2006. It is unclear whether these populations are newly established or whether the species was previously overlooked. No significant distribution trend data in Finland and Sweden points towards a decline, but it seems more likely that the species may be discovered in more locations in the future as there is hardly a lack of suitable habitat, and the species seems to be able to establish itself far from previously known sites (Billqvist et al. 2019). There are also unconfirmed sightings from Norway and Ukraine. Historical data claims that the species can occur in large swarms. In some areas, such as around the southern Urals, it is common, and it can occur locally abundantly in some of the Baltic areas (Yanybaeva et al. 2006, Kalkman 2010). At present, however, there are no observations in Sweden involving more than ten individuals. In Denmark, it is red-listed as Vulnerable and we know very little about its occurrence in most of European Russia. In the rest of its European range, it appears to be either fairly stable or expanding, and there is currently no reason to believe it is declining.

In the interior of Sweden, A. serrata occurs in small to very large eutrophic lakes and large ponds with extensive reed beds in open landscapes. The largest populations in and around the Baltic Sea are most often found in coastal reed lakes and lagoons that may be brackish (Billqvist et al. 2019). In southern Ural, the species is found in steppe and forest-steppe lakes (Kalkman 2010). In Arkhangelsk, the species is found in clear water lakes partly affected by karst water and with fairly abundant and tall vegetation dominated by reeds and some sedges (Bernard and Daraz 2010).

A. serrata is a large and powerful species that even catches other Aeshna-species. It forages in warm, open clearings and wind-protected fields. Individuals are also seen flying very low and slowly, just a few decimetres above the ground, back and forth, methodically searching for prey. The male primarily patrols over reed beds. During patrolling, the territory is defended very aggressively. Although A. serrata is large and eye-catching, it can be surprisingly difficult to see. This is at least partly since the male during patrolling flies along openings and channels that are surrounded by reeds and is therefore hidden from view. The female lays eggs low in stalks of reeds. The larval development lasts two years or longer. The exuviae are often found a few decimetres up on stalks of reed (Billqvist et al. 2019).

Currently, no specific threats are known, and the species is locally common and seems to be expanding its range in Sweden. However, little is known about the situation in large parts of its range and the development of tourism along the coasts of Estonia and Finland could possibly pose a threat to the species. It is not unlikely that most of the Baltic Sea population breeds in the Baltic Sea or in habitats strongly affected by seawater. Changes in the water quality of the Baltic Sea through, for example, climate change can therefore potentially pose a threat. Management plans that include the removal of reed beds in protected bird areas and flooding for bird protection measures have been put forth as having negative impacts on the species (Kalkman 2010).

There is no trade or use of this species.

Relatively little is known about the biology of the species and the different types of habitats adjacent to the Baltic Sea. Information on this is needed to better understand its conservation status. The distribution of the species in Russia outside the Urals is very poorly known. Information on this would help in understanding the conservation status.