Restoring native bushland to its pre-disturbance state is complicated. When that disturbance comes after decades of mining on threatened wetland and bushland, it’s fair to say environmental restoration requires a little extra planning.
Since 2013 Lake Macquarie Council has been actively working to regenerate a 40.9 hectare site at Jewells after sand mining operations closed in the late 1970s leaving behind a vastly changed landscape.
The success of its efforts, possible under a Biodiversity Stewardship Agreement with the NSW Biodiversity Conservation Trust (BCT), has restored 27 species, 10 that were not present before regeneration efforts.
Lake Macquarie Council signed a BioBanking agreement for Fencott Drive Wetland Reserve which later transferred to a Biodiversity Stewardship Agreement, to restore the site after it was identified as a green corridor of strategic conservation value. As part of the agreement a Total Fund deposit was set and has funded most of the work and management provided by Lake Macquarie Council.
Past sand mining and attempts to revegetate the site left it dominated by tea trees and invasive weeds.
Ecological burn stimulates dormant seed bank
However, Lake Macquarie Council Senior Natural Assets Officer Dominic Edmonds said conservation management efforts had delivered impressive results, with a recent 5.7 hectare ecological burn stimulating the soil seed bank that had been lying dormant for years and reinvigorating native vegetation.
“The remediation of the sand mine involved seeding the site with tea tree and that had become dominant and was deteriorating with age. It was essentially a monoculture where we didn’t have a lot of diversity,” Mr Edmonds said.
“We thought there was enough diversity present above ground to indicate there was a good soil seed bank. To stimulate that soil seed bank, we did a moderate intensity burn so that we could get the heat down into quite a disturbed sandy soil profile.
“About two and half years ago we began extensive preparation work and culled about 90 per cent of the older tea tree, leaving the younger, healthier leptospermums in place, so they could still recruit post fire and get back to a more natural species composition.
“Then 18 months ago we undertook a moderate intensity burn through most of the site.”
Mr Edmonds said there were areas of swamp sclerophyll forest, riparian zones, and spots where threatened species required fire exclusion, but it was planned for ahead of the burn.
“It was all taken into consideration and thankfully it was really successful,” he said.
Mr Edmonds said ongoing monitoring takes place every three months, with rich data coming from three quadrats within the burn area as well as 15 photo monitoring points across the site. That data shows a 69 per cent increase in species richness post-fire.
“We have recorded 27 new species within the monitoring quadrants that weren’t present before the fire,” he said.
“Also 10 species have been recorded post-fire that weren’t previously recorded in the area at all. So that’s really exciting results.
Those new species include Macarthuria neocambrica, Pseudanthus orientalis and Amperea xiphoclada (broom spurge).
There are plans to do more burns in at four new burn sites within the Biodiversity Stewardship Agreement area.
“We have another site similar but will wait until the previous burn reaches maturity and can provide some habitat, before we look to undertake the next stage,” Mr Edmonds said.
“We have two other areas on site that are in scribbly gum forest and have had good previous fire intervals. We’re looking to undertake that burn probably next winter, weather pending, and hopefully we will see great results from that.”
Lake Macquarie Council is looking at establishing new BSA sites as part of its conservation framework to complement development in the local government area.
"That's likely to involve purchasing land specifically for this purpose, rather than using existing Council reserves that are already considered conserved or reserved," Dominic said.
NSW Biodiversity Conservation Trust Senior Ecologist, Mike Lawrie, said the Agreement partially sits on Swamp Sclerophyll Forest and Sydney Freshwater Wetlands ecological communities, both of which are listed as endangered under the NSW Threatened Species Conservation Act.
"The condition of much of the vegetation within the BSA site was degraded, primarily by invasive weeds such as lantana," he said.
"Works undertaken by Lake Macquarie Council has seen some great results for biodiversity improvement and we look forward to helping with its continued management and restoration through sustained, long-term bush regeneration and fire management."
Fencott Drive Wetland Reserve
Fencott Drive Wetland Reserve includes part of the Jewells wetlands and is on the traditional Country of the Awabakal People. The wetlands are recognised as areas of high conservation value by their inclusion on state and national registers of important wetlands.