Category Archives: Western Australia

Integrated predator management on the south coast of Western Australia

Key words: predators, feral cat, adaptive management, natural area management, threatened species

Allan Burbidge

The Western Ground Parrot (‘kyloring’ to Noongar people) may be the ‘canary in the coal mine’ warning of imminent fauna collapse on the south coast of WA. Over the past decade, this species has undergone a dramatic decline, with the population currently estimated at 140 individuals. This is causing alarm bells to ring, as there is concern that a range of other threatened animals on the south coast may be at risk from the same threatening processes – species such as Gilberts Potoroo, Red-tailed Phascogale, Dibbler, Noisy Scrub-bird, Chuditch, Western Bristlebird and Malleefowl. Considerable progress in fire management strategies for these species has been made by WA’s Department of Environment and Conservation (DEC) over the last few decades, and fox baiting under the Department’s Western Shield program has been in place since 1996. Despite these programs, however, the Ground Parrot population decline continued, leading to the hypothesis that control of foxes has resulted in an increase in the feral cat population (i.e. mesopredator release), with a corresponding increase in predation on native fauna.

Releasing a collared cat (Photo: Emma Adams/WA DEC)

Field trials of Eradicat® baits have been completed under a research permit in Fitzgerald River National Park. Half of the collared cats were killed by these baits, and bait uptake by non-target species was minimal. In 2011 this trial has been extended to include Cape Arid National Park where 19 cats have been fitted with collars, providing direct evidence of bait uptake. Monitoring of predator activity provides additional information on the success of cat baiting. Should this strategy prove effective, the benefits in the wider landscape will be significant.

Feral cat with bandicoot (Photo: WA DEC)

Several clear lessons arise from this work. First, it requires meaningful and ongoing interaction between researchers and managers to carry out robust field-scale adaptive management projects. Second, we have found that institutional barriers such as inappropriate funding timelines can waste the time of project leaders required to continually secure funding and retain skilled staff. Finally, while there is notional support for adaptive management, it is difficult to convince people to support its implementation adequately.

Putting a radio-collar on feral cat (Photo: Emma Adams/WA DEC)

Funding for this project has come from the Department of Environment and Conservation, State NRM, South Coast NRM Inc, Exetel Pty Ltd, Birds Australia and many volunteers. Numerous people have been active in this project including Sarah Comer, Cameron Tiller, Allan Burbidge, Abby Berryman and Deon Utber.

Further reading:
Comer, S., Burbidge, A. H., Tiller, C., Berryman, A., and Utber, D. (2010). Heeding Kyloring’s warning: south coast species under threat. Landscope 26(1), 48-53.

Contact: Sarah Comer (Department of Environment and Conservation, 120 Albany Highway, Albany, Western Australia 6330; tel (08) 9842 4500; email sarah.comer@dec.wa.gov.au) or Allan Burbidge (Department of Environment and Conservation, PO Box 51, Wanneroo, Western Australia 6946; tel (08) 9405 5100; email allan.burbidge@dec.wa.gov.au)

Fire management at Two Peoples Bay – Mt Manypeaks, Western Australia

Key words: environmental management, threatened species, collaboration, communication

Allan Burbidge

Fire management is a major challenge where there are multiple conservation values and potentially conflicting adjacent community values; the challenge is further exacerbated in landscapes involving rough terrain where access for fire management is difficult. All three factors occur in the Two Peoples Bay – Manypeaks area in south-western Australia, which is mostly conservation estate, with some water reserves, and surrounded by private land. In this often steep and rocky landscape, there are threatened vertebrates such as the Noisy Scrub-bird and Gilbert’s Potoroo, threatened plants and short range endemic relictual invertebrates, all with different habitat requirements, and therefore different management requirements. Superimposed on this are community values which involve the surrounding relatively small private holdings, with homes, timber plantations, stock and agricultural infrastructure

Bushfire on Mount Manypeaks (Photo: Ed Hatherley)

Fire management by the State conservation agencies in the area during the 1970s focussed on fire exclusion, as it was believed that this was optimal for the locally endemic and newly rediscovered Noisy Scrub-bird. However, this resulted in dangerous fuel levels, posing a threat to this species and other conservation values. Despite the need to reduce the threat, only minimal use of prescribed fire was able to be applied to manage fuel levels, because of the area’s difficult terrain and the requirements for many species for long interfire intervals.

Water bomber on route to fire (Photo: Sarah Comer)

The problem seemed intractable until local managers, researchers, senior agency managers and policy makers were brought together to debate the options in a focussed meeting. After considerable debate, this group agreed that selected prescription burns in the untracked zones of Mt Manypeaks could be carried out and some patchy ignition could be initiated on the upper slopes by aerial ignition, in a way that minimised negative impacts on populations of threatened species. This in itself was a challenge, as virtually everywhere in the 28 000 ha study area provided habitat for at least one threatened species.

Noisy Scrub-bird (Photo: Alan Danks)

This process is ongoing and adaptive, particularly in the sense that wildfires extent and impact can never be predicted, but some key points have emerged. First, no single group had all the answers or expertise to understand the complex situation, underlining the importance for all practitioners to embrace dynamic and ongoing partnerships. Progress only came with co-ordinated and collaborative commitment from researchers, policy makers and managers. Second, we found that generalised models are inadequate for (complex) individual cases, particularly where there are multiple species of interest, and these species have different management requirements. Third, the old linear model of management was simply not functional; new knowledge and assumptions concerning the dynamic nature of the threatened fauna and flora populations demanded dynamic management, preferably in an adaptive management framework.

Mount Manypeaks after fire (Photo: Sarah Comer)

Major players in this process have come from Nature Conservation Division and Science Division staff within the Department of Environment and Conservation, with species specific input from the South Coast Threatened Birds Recovery Team, Gilbert’s Potoroo Recovery Team and the Albany District Flora Recovery Team.  Strong collaboration with other land managers such as Water Corporation and plantation managers is essential for the successful management of the conservation interface with other land uses.

Further reading:
Comer, S., and Burbidge, A. H. (2006). Manypeaks rising from the ashes. Landscope 22(1), 51-55.

Contact: Sarah Comer (Department of Environment and Conservation, 120 Albany Highway, Albany, Western Australia 6330; tel (08) 9842 4500; email sarah.comer@dec.wa.gov.au ) and Allan Burbidge (Department of Environment and Conservation, PO Box 51, Wanneroo, Western Australia 6946; tel (08) 9405 5100; email allan.burbidge@dec.wa.gov.au)

The Ridgefield Multiple Ecosystem Services Experiment: restoring and sustaining function in degraded ecosystems

Key words: carbon sequestration, invasion resistance, nutrient cycling, novel ecosystems, intervention ecology

Mike Perring

Introduction. Multiple, simultaneous, and rapid environmental changes make sustaining and restoring ecosystem functions an increasingly important but challenging task. The Ridgefield Multiple Ecosystem Services Experiment, being undertaken at the University of Western Australia’s Future Farm in the Western Australian wheat belt, tests the application of current ideas in ecology to ecological restoration, and seeks insights into how management interventions can sustain and restore multiple ecosystem functions in an era of rapid environmental change.

Design. Our experiment tests how different woody plant species mixtures affect provision of ecosystem functions and services, including carbon storage, nutrient cycling, invasion resistance, biodiversity maintenance, and prevention of soil erosion. We also consider potential tradeoffs in the provision of ecosystem functions, how different plant species mixtures may respond to simultaneous environmental changes, and how different plant species assemblages may affect other trophic levels, both above and below ground.

Experimental treatments, across 124 23x11m rip line plots, comprise native tree and shrub species, and span a diversity gradient from bare and single-species to mixtures of eight species. Species belong to four different functional groups based on differing nutrient acquisition strategies and morphologies. Plant assemblage treatments are replicated across former grazing and cropped landscapes.

The Ridgefield experimental site with formerly cropped area to the right and grazed blocks in middle and left (December 2010)

In addition to the role of species composition in determining ecosystem functions and services, we will examine the effect of simultaneous environmental changes (nitrogen deposition and weed invasion) on our chosen functions and services, particularly since the presence of exotics creates potentially novel ecosystem states. Our experiment will allow us to understand more about how combinations of plant species, and their associated traits, can be utilized to intervene and manage ecosystems to ensure capacity for ongoing function and service provision in the Anthropocene. In terms of theory, we are also interested in whether the provision of multiple ecosystem functions requires greater biodiversity than provision of single services, if there are tradeoffs among services as diversity levels increase, and how the traits of included species affect functioning.

York gum only plot (January 2011)

Participants and potential for collaboration. Participants include: Mike Perring, Kris Hulvey, Rachel Standish, Lori Lach, Tim Morald, Rebecca Parsons and Richard Hobbs. The study provides a platform for the investigation of a wide variety of ecologically and socially important questions, and we encourage interested parties to contact us should they wish to collaborate or conduct trials at the site.

Contact: Mike Perring, School of Plant Biology, University of Western Australia; Tel: +61 (0)8 6488 4692; Email: michael.perring@uwa.edu.au

Translocation of the Corrigin Grevillea (Grevillea scapigera), Corrigin, WA

Key words: Critically endangered, genetic diversity, cryostorage, site preparation, species richness

Bob Dixon

Corrigin Grevillea (Grevillea scapigera) is listed as an Endangered plant under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and as Critically Endangered under the Western Australian Wildlife Conservation Act, 1950. Naturally occurring in heathland and low myrtaceae and proteaceae scrub, the species is known from 13 wild populations, mostly in highly degraded narrow road verges. Attempts were made to obtain, for its restoration, farmland adjacent to the largest known roadside population; but these attempts were unsuccessful. Therefore, translocation of the species to three other distal sites was necessary.

All of the translocation sites, each 0.2 hectare, were previously cleared bushland remnants, at various stages of regrowth and degradation. Compaction was a major problem on two sites [e.g. on an old airstrip, weed invasion particularly Capeweed (Arctotheca calendula) and Onion Grass (Romulea rosea) needed to be addressed; as well as grazing by rabbits].

Bullaring site, vegetation skimmed off, ready for planting in winter 2000.

Works undertaken: Site works included scalping off vegetation (on one site) and partial clearing and ripping (at the other sites); followed by rabbit proof fencing, weed control (ongoing) and the installation of trickle irrigation systems. Initial planting was undertaken with tissue cultured plants, 10 clones representing 87% of the known genetic diversity. Through this process, cryostored clones have been retrieved, grown on and successfully translocated on site. Planting numbers varied from year to year, and totaled several thousand over the life of the project.

Bullaring Oct 2003, the perfect result re-sprouting and seedling recruitment of indigenous species retaining biodiversity on site and resisting weed invasion. (Corrigin Grevillea is the white flowered plant visible in the rows closer to the fenceline.)

Results to date: Plant numbers on all sites, at one time over 1800, have dramatically declined since planting ceased, as this species is a short lived disturbance opportunist – and now total about 400.  However, millions of long lived seeds have been contributed to the soil seedbank. Regeneration from the seedbank has occurred on all sites. (See figures 1-3)  Genetic decline was addressed by planting the more under-represented clones. Restoration of other indigenous species, species richness and cover varies from site to site (See Dixon and Krauss 2008).

Site 1, the most degraded site, is where most of the research is carried out including burning, soil cultivation and smoking to stimulate the soil seedbank.

Lessons learned and future directions: This translocation, based on Dr Maurizio Rossetto’s PhD project, was well researched and coupled with sound horticultural practices. As a result, it has proved very successful and thousands of seeds are in long term storage. Fundamental to plant survival has been fencing to prevent predation by rabbits, water reticulation and the use of quality greenstock. Choosing a good quality weed free site is also essential for achieving a sustainable system. Spraying to prevent seed predation by weevils and caterpillars was also found to be critical to successful seed production.
Stakeholders and Funding bodies: Funding NHT, WWF. A joint project with Department of Conservation and Land Management, Corrigin Shire, Kings Park Volunteer Master Gardeners.

Contact: Bob Dixon, Manager Biodiversity and Extensions, Botanic Gardens and Parks Authority, Fraser Ave., West Perth, Western Australia, 6005. Tel +61 (0)8 94803628: Email: bob.dixon@bgpa.wa.gov.au

Reference: Dixon B. and Krauss S. (2008).  Translocation of the Corrigin grevillea in south Western Australia. Pages 229-234 in Soore, P. S.(ed) Global re-introduction perspectives: reintroduction case-studies from around the globe. IUCN/SSC Re-introduction Specialist Group, Abu Dhabi, UAE.