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

Ophiogomphus cecilia has a wide range and is fairly common. It has recovered and even expanded since the 1990s, probably because of an increased water quality and a more natural management of river systems. It is Regionally Extinct in Luxembourg and threatened in Austria, Bulgaria, Croatia, the Czech Republic, France, Germany, Latvia, the Netherlands, Slovakia, Slovenia, Switzerland, and Ukraine. Some of the historical threats to the species have ceased or lessened, especially water pollution, but it is affected by drought, water extraction and canalisation. The current situation is somewhat difficult to interpret as it can be regionally or locally abundant and perhaps even still expanding, while elsewhere show an ongoing reduction. Although it is declining in some regions, the negative trend is more modest than the positive one. It is probably also more widespread in large parts of Eastern Europe than we know of today. O. cecilia is thus considered to be Least Concern in Europe as well as in the EU27. However, the species' situation could quickly change for the worse if the threats do not stop, so the development should be monitored, and if a change in a more negative direction occurs, a different assessment in the future may be relevant.

O. Cecilia is a Palearctic species with a more or less continuous range from western France to Lake Baikal in the east. It is widespread in central and north-eastern Europe, with a more fragmented and gradually less frequent occurrence in the south and in the north-west. In the latter areas it is often limited to single rivers, such as the Po in Italy and the Loire in France. It is probably more widespread in large parts of Eastern Europe than we know of today. It is absent from the British Isles, the Iberian Peninsula, islands in the Mediterranean, southern Italy, and large parts of Fennoscandia (Kalkman 2010, Kalkman and Ambrus 2015).

O. cecilia declined strongly in parts of its range during the first three-quarters of the last century. In the latter part of the 1900’s and early 2000s’ the species recovered in step with better water quality and a more natural management of river systems. It re-appeared in some areas and regionally expanded its distribution. It is widespread in central and north-eastern Europe, and in the latter area probably more so than current data suggest. It has a more fragmented and gradually less frequent occurrence in the south and in the north-west. Old records from the Iberian Peninsula are regarded as incorrect (Kalkman and Ambrus 2015). The recovery has mostly ceased, possibly in connection to a halted improvement of water quality, and the current situation is somewhat difficult to interpret. It can be regionally and locally abundant, or even still expanding, while elsewhere showing a reduction. The ambiguity of its trend is obvious in Switzerland, where the species has been found in many new locations, but frequently occurs with only single individuals and reproduction is only demonstrated exceptionally (Monnerat et al. 2021).

O. cecilia occurs mainly in lowlands along several different types of watercourses with sandy bottoms. At its most northern sites in Sweden and Finland, it is mainly found in large and at most partly shaded, rather fast-flowing rivers and tributaries. In Denmark, it is found along large, wide, and slowly flowing watercourses. In southern Finland and further south it is also found in smaller watercourses that are at least partly unshaded. It is mostly absent from watercourses that are muddy or have very strong currents (Billqvist et al. 2019, Kalkman 2010).

O. cecilia is most easily found by looking for territory-holding males that perch on rocks and branches near fast flowing parts of watercourses on warm sunny days. In smaller watercourses it is therefore easy to find, but in large, wide rivers or streams binoculars may be necessary. In the morning before they start holding territories, males can be found perching on the ground close to the waters’ edge. Individuals away from the breeding habitats on the other hand can be shy and difficult to approach. These are found in sun-exposed locations in clearings, on sun-heated surfaces such as paths, forest roads and exposed sand. The larval development lasts two to four years. The exuviae are found a few decimetres from the water edges on straws, bare ground or on bridges etc (Billqvist et al. 2019). Due to currents, larvae can drift and larvae and exuviae are thus often found in places where no adults are seen, and vice versa.

O. cecilia is Regionally Extinct in Luxembourg and threatened in Austria, Bulgaria, Croatia, the Czech Republic, France, Germany, Latvia, the Netherlands, Slovakia, Slovenia, Switzerland, and Ukraine. On the other hand, it is probably more widespread in large parts of Eastern Europe than we know of today, and it is still expanding in several regions. Some of the historical threats have ceased or lessened, especially water pollution, but locally a general degradation of water quality might still be an issue for riverine species (Boudot & Dommanget 2015). Canalisation of water systems can still pose a threat, as it causes high fluctuations of water levels and seasonal droughts. In some river systems waves caused by large boats might lead to an increased mortality of emerging adults and damage to riverbanks (Kalkman and Ambrus 2015). Introduction of invasive crayfish may also be a threat as they have been on some other riverine species (Boudot and Dommanget 2015). 

As shown during the last couple of years even large rivers can be subject to drought during increasingly hot summers. Recurring and increasingly severe and longer droughts are a major reason why riverine species are decreasing. The drought is partly due to climate change but is often worsened by an ever-increasing withdrawal of water for human use and irrigation. Lower water levels mean higher water temperatures, which changes pH values, nutrient content, and species composition. Higher water temperatures lead to a lower oxygen availability for the larvae which leads to higher mortality, change in larval development and flight period. In the past, species has been able to re-immigrate to places that have dried out during certain years, but as droughts return more and more often and more severely, there are fewer suitable sites to disperse to and from (Kalkman 2010, Kalkman and Ambrus 2015).

There is no trade or use of this species.

No specific conservation measures are needed on a European scale; the species is already protected under the EU Habitats Directive (Annex II). However, local measures should be applied for those populations that are under threat and catchment management plans should be drawn up with particular attention to ecological flows in accordance with the European Water Framework Directive (WFD CIS, 2015). This should mitigate or even prevent water abstraction for agricultural or domestic use from streams and rivers.