The Azure Hawker (Aeshna caerulea) is a dragonfly species characterised by distinctive azure-blue spots on its abdomen and thorax that are more vivid in males. The males have bright blue eyes, whereas the females have brown eyes. The males also exhibit an interesting temperature-dependent colouration feature, where their markings and eye colour shift from pale purple-grey in colder temperatures to bright blue in warm temperatures.
According to the IUCN Red List criteria, the Azure Hawker is classified as Near Threatened in Europe. In the UK, their population is classified as Vulnerable on the British Odonata Red List and their distribution is restricted to a small number of blanket bogs in the Scottish Highlands. They are found in small populations in the Highlands, with a population in Dumfries and Galloway likely now extinct and . face strong threats from climate change and anthropogenic pressures.
The larvae of Azure Hawker are predatory and well camouflaged with the Sphagnum moss in peat bogs. Adult Azure Hawkers predate on small flying insects whereas the larval hawkers feed mainly on aquatic invertebrates and tadpoles. The species prefers nutrient-poor acidic habitats like peatlands and avoid densely vegetated or shaded areas.
The Azure Hawker has a very specific habitat requirement; although they prefer acidic habitats, they are intolerant to acidification beyond natural peat levels and rely on consistent humidity and insulation from peat bogs. The adults can be seen from late May to August. They also display strict diurnal behaviour and enjoy basking in the sun to regulate their body temperature.
Photo: Volkmar Wagner, (CC BY-SA 3.0)
Action Needed
- Push for increased funding for the protection and restoration blanket bogs
- Advocate for mandatory ecological impact assessments by independent experts that evaluate long-term hydrological consequences for peat bogs as a result of renewable energy projects.
- Advocate for stricter controls on extraction and sale of peat for horticulture.
- Advocate for ending afforestation on deep peat. Support measures that prevent the re-seeding of non-native tree species onto peatlands from plantations
- Support incentives for regenerative agriculture especially in farms surrounding peatlands to reduce chemicals and nitrogen leaching into peat bogs. Also advocate for chemical-free corridors around peatlands to prevent the influx of chemicals that degrade bog hydrology.
Threats
Only around 20% of UK peatlands are in a natural, or semi-natural state meaning that 80% have been altered by damage or drainage. Azure Hawker larvae require stable, wet conditions for about 4-5 years during its developmental stage. Damaged bogs lose their ability to hold water which are exacerbated by climate change impacts, causing the vital breeding bog pools to dry out. Bog pools in key sites like Corrour have dried out completely during dry summer months, with larval count dropping from 139 to just 3 in affected pools.
Peat extraction for horticulture removes peat-forming Sphagnum moss and drains bogs, accelerating drying and exposing these pools to temperature fluctuations.
Re-seeding of invasive non-native Sitka Spruce/ afforestation on peatlands, particularly on shallow peat soil significantly alters bog hydrology and causes drying of the peat bogs.
Renewable energy projects – Developments on peatland including wind farm infrastructure, hydropower plants and Pumped Storage Hydro Schemes (PSH) can alter catchment water levels, increase nutrients and sediment flow and destabilise the bog ecosystem. Inundation and fluctuating water levels as a result of PSH schemes threaten Azure Hawker populations as they require stable shallow pools for breeding.
Inappropriate burning leads to loss of Sphagnum and subsequent peat desiccation, shrinkage and erosion.
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