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| 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
