|Photo: F Forest
Petalurid dragonflies are a relict family originating in the mid-Jurassic ages. The Coastal Petaltail Dragonfly (Petaleura litorea) was separated from the Giant Dragonfly or Southeastern Petaltail Dragonfly (Petaleura gigantea) as a distinct species in 1999. The Coastal Petaltail is impressive with a wingspan up to 12.5 cm. Unlike other dragonfly larvae which mostly live in water, this species requires damp peaty soils with a high and variably emergent water table for the hatched larvae to burrow down into soil, spending probably at least five years in their underground burrows before emerging into adult dragonflies.
Petalura litorea is listed as endangered in NSW. The NSW Government's Save our Species program classifies it as 'data deficient' species, and, therefore dependent on further information into all aspects of its life-cycle and habitat requirements. As part of this process, Dr Ian Baird, an expert who has spent many years studying both species, recently undertook investigations of known observations as part of a knowledge review of the species. Up until this time, only a few known breeding sites were confirmed in NSW.
Local ecologist, Mr. F. Forest, photographed a mating pair in 2009 near Tyndale. That photograph was forwarded to the Australian Museum, where the identification was confirmed. Despite the recent 2009 sightings, surveys by consultants to RMS (NSW Roads and Maritime Services) on the Pacific Highway upgrade failed to locate any individuals of the Coastal Petaltail, although “ecologists undertaking the survey did note some potential breeding habitats associated with wetlands in the project corridor”. Despite this the consultants’ report concluded that there was no suitable breeding habitat.
After recently assisting Dr. Baird, Mr Forest located three other populations which highlighted a variety of swamp habitat types used by the species for reproduction. One site is impacted directly by the new highway route and two are within 200 metres of it. Hopefully work undertaken by scientists like Dr Baird and Mr Forest can help provide the additional data needed to develop an action plan for the species’ recovery, advance our scientific knowledge, and ensure that the new highway does not negatively impact upon breeding sites of this ancient species.
- John Edwards