Multiple work days this year will assist the natural regeneration of Rocklea Swamp. Bookings essential for catering purposes. Morning tea and lunch provided by Hominy Bakery.
Petalura gigantea (Family Petaluridae), commonly known as the Giant Dragonfly or Southeastern Petaltail is a very large dragonfly which may have a wingspan up to 12.5 cm. It is recorded from peat swamps, bogs and seepages along the coast and ranges of NSW from near the Victorian border to around the Qld border. It is listed as Endangered in NSW under the NSW Biodiversity Conservation Act2016, with habitat loss and degradation identified as the main threats. In addition to the large size and widely separated dark eyes, the species (and genus) is characterised by a long pterostigma (darkened cell) towards the end of the leading edge of the wings, and large, petal-shaped, anal appendages in adult males (Figure 1). Adult females lack the conspicuous anal appendages and are somewhat bulkier than males (Figure 2). These features distinguish it from other very large dragonflies such as Austrophlebiacostalis. Various Bushcare and Swampcare sites in the Blue Mountains include peat swamp habitat of Giant Dragonflies.
The Petaluridae (“petaltails”) can be traced back to the late Jurassic and currently includes 11 known species around the world, including the endemic Australian genus Petalura with five species. The family is unique amongst dragonflies, in that larvae of nine of those species (including all Petalura species) excavate (sometimes complex) burrows which extend below the water table in peaty soils and which they occupy and maintain for their entire larval stage. The deepest burrow recorded for a petalurid worldwide was a P. gigantea burrow I investigated, which was 75 cm deep. These dragonflies have very long larval stages; extrapolation from recent studies suggests a larval stage of at least six years in P. gigantea, and possibly 10 or more in some situations. Larvae reach a length of 4.5-5 cm. Larvae feed on a range of small invertebrate prey within their burrows, including worms and nematodes, and are likely to act as ambush predators of larger prey from within their burrow entrances, feeding on above ground invertebrates, such as spiders, crickets, cockroaches, and perhaps small frogs, such as Crinia signifera. Larvae with submerged burrow openings in shallow pools can also prey upon other dragonfly or damselfly larvae within those pools. It is possible (but unknown) that they also leave their burrow openings temporarily to forage under suitable conditions, such as at night and during rain. I have recorded above ground chambers above their burrow openings, within litter layers and Sphagnum hummocks, which they may use for foraging purposes. Larvae leave their burrows and climb the nearest shrub or sedgeland vegetation to undergo emergence (ecdysis) to the adult stage, usually leaving their larval skin (exuvia) attached to their shrub or sedge emergence supports. The presence of exuviae confirms a site as a successful breeding site. Emergence may commence in early October in some years in some sites and extend into January, but normally appears to commence during November, at least in the Blue Mountains.
Adults live for a maximum of one summer flying season, which extends into February at least, with occasional late flying individuals having been observed on one occasion as late as mid-March in the Blue Mountains. Adults are predatory upon other flying insects during flight and consume a range of prey, including other dragonflies and damselflies, butterflies, moths, grasshoppers, cicadas, wasps, and various types of flies, including crane flies. Adults typically return to a perch to consume prey. Adults spend much time perched in sedgeland and shrub vegetation, interspersed with generally short flights associated with foraging, mating, and in the case of males, territorial interactions. Adult females typically leave their larval swamp habitat following emergence and only return to a swamp habitat for breeding purposes. There is no courtship behaviour and mating generally occurs in swamp habitat with the pair perched in sedge or shrub vegetation. Egg-laying (ovipositing) involves insertion of the ovipositor into the wet, organic-rich soil substrate, into fissures in the substrate, or amongst or under live or decomposing plant material overlying the substrate. Females typically walk along the soil surface or perch within covering vegetation or on litter while ovipositing. They do not appear to oviposit into substrate covered by more than 1-2 mm of water. Most adults encountered in swamp breeding habitats are males, who are typically territorial in swamp habitat. Predation of adults by birds, skinks and spiders has been observed and dead individuals have been found in spider webs.
Petalura gigantea is considered to be an obligately groundwater-dependent species. Although the burrowing larval habit confers ecological benefits, including increased environmental stability, and some protection from the effects of fire, flood, drought and above ground predators, the species groundwater dependence and restriction to peat swamp habitats places it at increased risk in the event of any reduction in groundwater levels (e.g., due to groundwater abstraction, tunnel or pipeline boring, and longwall coal mining), more intense fire regimes, and the potential compounding effects of rapid climate change. Loss and degradation of habitat as a result of urban and transport infrastructure development, agriculture, forestry, and longwall coal mining continue to threaten the species through loss and degradation of habitat.
Figure 1. Male Petalura gigantea perched on razor sedge, Lepidosperma limicola, in a Blue Mountains Swamp. Note the conspicuous petal-shaped appendages at the end of the abdomen. Photo: Ian Baird
Figure 2. Female Petalura gigantea perched on Acacia ptychoclada in a Blue Mountains Swamp. Photo: Ian Baird
The Swamped by Threats Project, a partnership between BMCC, CTLLS, NPWS and Forest NSW, has reached the halfway mark. The project aims to conserve the ecological integrity and habitat quality of priority swamps for the endangered and swamp dependant Blue Mountains Water Skink and the Giant Dragonfly of the Blue Mountains and Newnes Plateau. The innovative ten year project is funded through a $750,000 Save Our Species (SOS) Partnership Environmental Trust grant.
A key focus of the project in the Blue Mountains has been the restoration of the natural hydrology of swamp systems which have been disrupted by stormwater flows from urbanised catchments, resulting in erosion, channelisation, de-watering, sedimentation, and weed invasion. Works have included stormwater outlet stabilisation, gross pollutant traps, raingardens, stormwater infiltration and integration structures and soft engineering swamp rehydration structures, as well as weed control. The sixteen priority swamp systems being targeted include Connaught, Yosemite, Marmion Road, North Street, the Gully, McCrae’s Paddock, Leura Falls, East Leura, Jamison Creek, Central Park, Wentworth Falls Lake, Franks Creek, Kittyhawke, Duperry/Clarendon Swamp, Red Gum Park, Lawson Pool and North Lawson Swamps.
A big thank you goes out to all the Bushcare and Swampcare volunteers whose ongoing on-ground efforts are making such a valuable contribution of in-kind hours in support of the grant funded work.
This project has been supported by the Hominy Bakery in Katoomba who provide the catering for these events “You know the food is good when everyone’s silent” said Katy O’Neill at the Valley View Swampcare Event.
Integral to Bushcare is depth of knowledge, understanding and leadership, and we are delighted to introduce you to our new Bushcare Officer, James Bevan. James will be taking over the Swampcare Program.
James has ten years’ experience in both aquatic and terrestrial Australian ecosystems applying his knowledge and skills across a variety of fields from ecological consulting, bush regeneration and training young adults. James’ studied a BSc.(Hons) at Sydney University, and his previous employers have included The Good Bush People, Conservation Volunteers Australia and The Australian Museum. James began appreciating the Blue Mountains’ bushland as a teenager, and is thrilled to be working as a Bushcare Officer.
Want an alternative to the ‘other’ live streaming viewing currently on
offer.
We aim to provide a platform on the Bushcare Website showing previous videos featuring bushcare sites, volunteers, Bioblitz, community days, fauna and much more.
However, the exciting news is the Bushcare Team (and others in Council’s environmental team) are also preparing to front the camera themselves to produce a host of videos highlighting a range of ‘interesting’ and ‘how to’ segments – such as showing different weeding techniques, treating a variety of common or tricky weeds and a range of videos showcasing flora, fauna, bees, seed collection, biofilters, composting, biosecurity, bush backyards and so much more.
Find out all about the recent launch of “Turtle Island” in early March – a floating eco habitat designed to provide a safe nesting place for turtles, from leading turtle expert Dr Ricky Spencer (Western Sydney University).
GORILLAS IN THE SWAMP (G.I.T.S.) are a dedicated group of Swamp-carers whom have been heroically spending their own time to fight back the weeds and take care of the invaluable and endangered ecological area that is Valley View Swamp in Blackheath.
There have been numerous Swampcare events at Valley View Swamp in the past which have made marked improvements in the health and condition of the site. Even with these accomplishments, we have recognised that the challenges facing us require a bolstered approach and a monthly meet-up in order to revamp the regeneration of the natural environment here.
WHY ARE SWAMPS SO IMPORTANT? – Blue Mountains Swamps are biologically diverse plant communities that occur nowhere else in the world. The swamps provide crucial habitat to a number of Threatened Species including the Blue Mountains Water Skink (Eulamprus leuraensis) and the Giant Dragonfly (Petalura gigantea). These swamps also play a vital role in maintaining the water flows in the area’s creeks, waterfalls and ground-water by capturing and storing rainwater and then slowly releasing it over time. Swamps act as filters, purifying water prior to its release into the natural environment downstream. Blue Mountains Swamps are coming under ever increasing pressure and are very susceptible due to the edge effects of urbanization and urban runoff.
PLANNED NEW MANAGEMENT STRATEGY – Big plans are in store for Valley View Swamp with a new management strategy nearing completion. The stormwater issues will be addressed with the construction of sandstone water-retention basins, sediment settling ponds, bio-filtration systems and rock lined channel. As well as being aesthetically pleasing, these storm-water control structures provide the benefits of improving water quality, reducing sedimentation in the swamp, rehydrating ground water and creating habitat. We are looking forward to observe and document the progress throughout the works of this project. Of course, we will continue to remove and control the invasive species on the site and encourage native revegetation too.
GORILLA IN THE SWAMPS (G.I.T.S.) – Valley View Swamp, Blackheath
When: 2nd Thursday of the month 9:30am -12:30pm
Where: Meeting on the corner of Valley View Rd and Hargraves St, Blackheath
What to bring: Please wear weather appropriate clothing which you don’t mind getting dirty, sturdy footwear and gumboots if it’s wet. A hat, sunscreen, plenty of water and something for morning tea. Tools and gloves are provided.
For more information contact the Swampcare Bushcare Officer – Ed Bayliss Hack on 4780 5623 or by ebaylisshack@bmcc.nsw.gov.au
Swampcare is a hands-on way our community can come together to protect our unique Blue Mountains Swamps.
Blue Mountains City Council have been fortunate to have secured John Gooderham, author of The Waterbug Book (CSIRO Publishing), to deliver waterbug identification training workshops on the 29th and 30th October 2018 (probably at Old Ford Reserve, Megalong). These workshops are for Council staff, Bushcare/Landcare/Swampcare/Streamwatch volunteers, teachers and other community members.
If you would like to participate in the training, please contact Amy St Lawrence by Thursday 11 October to express your interest. Places are limited but we’ll do our best to accommodate everyone. You can complete either the Monday or the Tuesday workshop, or if super keen (and places are available), both!
Council’s Healthy Waterways team can then assist workshop participants to complete their own waterbug surveys with their Bushcare/Landcare/Swampcare/Streamwatch groups or schools, with data collected to be entered into the National Waterbug Blitz – https://www.waterbugblitz.org.au/
Do you have a swamp in your backyard or interested in swamp restoration?
Then come join us for this very special event in Hazelbrook, where you will learn the basic principles about swamp restoration whilst giving this swamp a helping hand.
The swamp is located off Rocklea Street, which is the very north end of the urban area and is still in its early stages of being restored, so there is plenty of primary work to be done on a variety of weeds – Erica, buddleia, privet, crofton weed.
A FREE delicious lunch and morning tea has been kindly donated by Hominy Bakery.
Bookings are essential so please RSVP via the link on this page or contact Stephanie at schew@bmcc.nsw.gov.au. by Thursday 20 September.