Dragonflies

Dragonflies are among the most ancient land-living species on the planet, having been in existence for almost 300 million years. They live in freshwater and wetlands such as ponds, lakes, rivers, marshes, fens and bogs.

There are several ways to tell dragonflies from damselflies. Damselflies are usually small, weakly flying insects that stay close to the waters edge or water surface. When at rest most species hold their wings along the length of their abdomen. The eyes are always separated, never touching. Dragonflies are usually larger, and can often be found flying well away from water. When at rest they hold their wings out from the body, often at right angles to it. The eyes are very large and usually touch.

Dragonflies usually lay their eggs under the water. The larvae live underwater for several weeks (or years, depending on the species) and go through a series of moults as they grow. The larvae eat almost any living thing that is smaller than they are. They emerge from the water when they are ready to go through their final moult where the 'skin' disappears to reveal the winged adult. Adult dragonflies mainly eat other flying insects, particularly midges and mosquitoes. They will also take butterflies, moths and smaller dragonflies.

Dragonflies and Damselflies are very sensitive to changes and pollution in their environment, which makes them very good indicators of the quality of wetland habitat.

Current Status

There are currently 38 dragonfly species breeding in Britain, of which seven are vulnerable because of their specialised habitats. Three species have already become extinct during the past 40 years. Three new species of dragonfly have come to live in Britain in the last few years and several species, which were previously scarce, have expanded in number considerably.

 The distribution of dragonflies and damselflies in Hull has not been studied in detail. A recent survey of North Carr, Bransholme revealed important populations of dragonflies and damselflies. Species found on the site include Blue-tailed Damselfly (Ischnura elegans), Common Blue Damselfly (Enallagma cyathigerum), Emerald Dragonfly (Lestes sponsa), Brown Hawker (Aeshna grandis), Common Darter (Sympetrum striolatum), Ruddy Darter (Sympetrum sanguineum) and Emperor Dragonfly (Anax imperator). The Emperor Dragonfly, regarded as Britain's most impressive dragonfly, is of particular interest on this site. This insect is generally recorded at the northern edge of its range at the Humber but is thought to be spreading northwards. This record is therefore of considerable importance. Migrant Hawkers (Aeshna mixta) were found in Pickering Park Lake prior to a herbicide accident in 1999. The status of this dragonfly in the Park is not known but it can still be seen over many house gardens in West Hull. Chanterlands Avenue crematorium supports Blue-tailed Damselfly and Common Blue Damselfly.

Current Factors Affecting Dragonflies

• Still water habitats within the British Isles have declined dramatically over the last 50 years. Farm ponds which traditionally provided a water supply for animals are usually no longer required. Unused ponds have dried out or have been filled in to provide additional land for agriculture or building. This loss of open water has resulted in a serious reduction of dragonfly populations.
  
  
• Modern land-drainage techniques have speeded up the decline of wetland habitats, either directly or indirectly, through the lowering of the water table.
  
  
• Ponds are subject to pollution, and those in urban areas are often used as refuse tips. Many ponds are simply neglected and become over-shadowed by trees and bushes. Ponds and lakes often become overgrown with water plants. Reeds and Bulrush are prone to dominate ponds therefore reducing the amount of open water and suitable habitats for the aquatic plants required by dragonflies.
  
  
• Damselfly and dragonfly larvae are vulnerable to predation by fish if these are kept in unnaturally large numbers.

Current Action

Legal Status

None of the dragonfly species occurring in Hull is specially protected under national or European legislation.

Management, Research and Guidance

The British Dragonfly Society produces information on managing habitats for dragonflies. This includes a leaflet 'Dig a Pond for Dragonflies' in which the general habitat requirements of British dragonflies are discussed as well as practical aspects of pond construction. The British Dragonfly Society has also recently appointed a Dragonfly Conservation Officer to encourage and promote research into dragonflies and their habitat nationwide.

Action Plan Aims

1. To determine the species of damselfly and dragonfly present in Hull.
   
2. To maintain or increase the number of ponds in the City.
   
3. To promote pond construction.
   
4. To enhance ponds to make them more suitable for dragonflies.
   
5. To encourage more wildlife-friendly management of ponds.

What We Are Going to Do

What We Can All Do

• Create a wildlife pond to provide a breeding place for dragonflies.
  
• Be aware of the need for the management of the City's park lakes for the benefit of varied wildlife.
   

Links With Other Action Plans

The plans for Fresh Water Habitats and Grassland will be important in the conservation of dragonflies. Actions for dragonflies may also benefit other species that require similar habitats, such as Great Crested Newt and Common Toad.

References

British Dragonfly Society (2000) Managing Habitats for Dragonflies. (Retrieved December 2001 from http://www.dragonflysoc.org.uk)

British Dragonfly Society (1990) Dig a Pond for Dragonflies. (Retrieved December 2001 from http://www.dragonflysoc.org.uk)

English Nature (1998) Managing Ponds for Wildlife. English Nature, Peterborough.

Holloway, S. (2001) BGEEP Biodiversity Project, North Carr, Bransholme. Bishop Burton College.

Merritt, R. (1996) Atlas of the Dragonflies of Britain and Ireland. HMSO, London.