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Australasian Plant Conservation

Originally published in Australasian Plant Conservation 21(2) September - November 2012, p 5-6

Better bush for your buck: targeting restoration efforts and exploring restoration methods in the lower Hunter Valley, NSW

Tricia Hogbin

Office of Environment and Heritage, Newcastle, NSW. Email tricia.hogbin@environment.nsw.gov.au

The Cessnock Biodiversity Management Plan was published as a poster in an attempt to highlight key objectives and facilitate implementation of the plan by landholders, community groups, schools and other government agencies

The Cessnock Biodiversity Management Plan was published as a poster in an attempt to highlight key objectives and facilitate implementation of the plan by landholders, community groups, schools and other government agencies. Photo: Tricia Hogbin

An experimental restoration plot for the threatened ecological community Lower Hunter Spotted Gum-Ironbark Forest approximately two years after revegetation

An experimental restoration plot for the threatened ecological community Lower Hunter Spotted Gum-Ironbark Forest approximately two years after revegetation. One of the more effective treatments that involved scalping and ripping can be seen on the right.
Photo: Tricia Hogbin

The native vegetation of the lower Hunter Valley has been extensively cleared since European settlement, with less than 30% remaining. The remaining vegetation is highly fragmented and subject to a range of threatening processes including continued clearing for residential and industrial development and habitat degradation.

Like many highly fragmented landscapes, it is clear that strategic restoration is needed to improve connectivity across the landscape. However, with limited funds available, and a 70,000 hectare project area, it wasn’t immediately obvious where restoration efforts should be targeted. In addition, almost all remnant vegetation within the project area, which spans the valley floor region of the Cessnock local government area, is recognised as threatened ecological communities under the NSW Threatened Species Conservation Act 1995 (DECC 2008), making it important that any restoration efforts be more than a tree planting exercise.

Two ongoing projects are shedding light on where restoration efforts should be targeted in the landscape and the methods that should be used to increase likelihood of success: the Cessnock Biodiversity Management Plan and the Experimental Revegetation of Threatened Ecological Communities in the Lower Hunter project.

Cessnock Biodiversity Management Plan

The Cessnock Biodiversity Management Plan (Office of Environment and Heritage 2011) spatially identifies priority actions for threatened species recovery across the project area and was introduced in Australasian Plant Conservation 19(3) (Hogbin 2011). The plan has since been published as a poster and was distributed widely among the community and made available online (http://www.environment.nsw.gov.au/biodiversity/cessnockmgtplan.htm). The reverse of the poster displays images for all 65 threatened entities occurring within the region.

The objective of the plan is to address the conservation needs of all 65 threatened entities occurring within the project area. Five key landscape corridors were identified based on the location of areas identified as a high priority for conservation. Areas of cleared vegetation within the landscape conservation corridors are identified as providing opportunities for revegetation. Restoration works within these targeted areas will likely contribute to the overall conservation of threatened entities and to landscape function more so than restoration outside of these targeted areas.

Experimental revegetation of endangered ecological communities in the Lower Hunter

This collaborative project with the University of Newcastle’s Centre for Sustainable Ecosystem Restoration aims to build capacity and understanding of how to most effectively restore threatened ecological communities in the Lower Hunter (University of Newcastle 2010). The project is large scale experimental restoration of the threatened ecological communities Kurri Sand Swamp Woodland and Lower Hunter Spotted Gum-Ironbark Forest in cleared pasture. The influence of a range of variables on restoration success is being studied, including scalping, ripping, direct seeding, tube-stock planting, and application of soil ameliorants.

The project will need to be monitored over the long-term to truly appreciate whether or not we can effectively restore threatened ecological communities. However, results for the establishment phase of the trials are already providing insight into how to improve chances of restoration success. For example, results to date indicate that both scalping and ripping can increase emergence and survival for some species (University of Newcastle 2010). Scalping presumably increases survival due to reduced competition from the grass layer for light, water and nutrients and the positive ripping effect is presumably a consequence of ripping de-compacting the soil, leading to greater water, air and root penetration.

A detailed cost-benefit analysis was undertaken to gain greater insight into the cost and value of each variable. This information will help develop realistic budgets for future restoration projects. For example, overall the most expensive components of the restoration were the collection and cleaning of seed (for both direct seeding and tube-stock propagation) and site earthworks. Scalping was the most time intensive and therefore costly of the earthworks, while ripping did not substantially increase costs. The cost of revegetation at a density of ≥ 3150 plants per ha ranged from c. $6,500 for seeded, not scalped and not ripped plots to approximately. $12,000 for planted & seeded plots that were ripped and ameliorated with lime and dolomite.

Conclusion

We now have a good understanding of where to target restoration efforts; the methods needed to increase the likelihood of success; and the likely cost of implementing these methods. The next stage in the project is to facilitate implementation. The Hunter-Central Rivers Catchment Management Authority is already undertaking habitat protection and restoration within one of the identified landscape corridors. A multi-partner project, bringing together a range of stakeholders including state and local government, community and landholders is currently being developed to seek funding to implement habitat restoration and protection across the broader project area.

References

Department of Environment and Climate Change (DECC) (2008). Vegetation of the Cessnock-Kurri region, survey, classification and mapping, Cessnock LGA, New South Wales. Department of Environment and Climate Change NSW, Sydney.

Office of Environment and Heritage (2011) Cessnock Biodiversity Management Plan, State of NSW and Office of Environment and Heritage NSW, Sydney. Available online http://www.environment.nsw.gov.au/biodiversity/cessnockmgtplan.htm

Hogbin, T. (2011) Progressing from single species recovery planning to multi-species recovery across the landscape: a case study from the Hunter Valley, New South Wales. Australasian Plant Conservation 19(3) p 15-16.

University of Newcastle (2010) Experimental Revegetation of Endangered Ecological Communities in the Lower Hunter. University of Newcastle, Newcastle NSW. Available online at http://www.newcastle.edu.au/research-centre/cser/

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