Restoring precious urban bushlands

Catherine McChesney (Ecological Scientist), Ryan Glowacki (Bushland Manager)

Wanju Wanju Nidja Noongar Boodjar ‘Welcome to Noongar Country’

Kings Park (Kaarta Koomba) and Bold Park were once part of a vast and highly diverse coastal plain ecosystem, freely accessed and cared for by the Whadjuk people.

Today, they are two of Perth’s largest remnant bushlands, dominated by Western Australia’s iconic banksia and tuart woodlands and forests, now recognised as Threatened Ecological Communities.

Remarkably, these two bushlands continue to support a rich diversity of local flora, fauna and fungi, despite two centuries of degradation following European settlement. Together, they contain at least 457 native plant species, with 225 of these species being unique to one or other of the bushlands even though they are less than 10 km apart, demonstrating the extraordinarily high species diversity of the Swan Coastal Plain.

Large areas of bushland located close to city centres are rare in the world, and Kings Park and Bold Park play an increasingly important role in improving our quality of life: park visitors gain much needed health and well-being benefits by engaging with nature, and on top of that, the bushlands help us out by improving air quality, reducing the urban heat island effect and storing carbon.

They are ideally located to inspire conservation of biodiversity, which is critical at a time in history when we are facing the twin global crises of climate change and biodiversity loss.

Strong community support for the conservation of Kings Park and Bold Park bushlands has led to significant restoration activities by enthusiastic volunteers and a Bushland team since the late 1990s.

The Friends of Kings Park Bushland Carers meet regularly with the Bushland team to help restore sites across Kings Park bushland. Photo: Geoff Chidlow

The Friends of Bold Park Bushland have been working hard at the Eastern Gateway Restoration Precinct since the late 1990s. Photo: Melissa Mykytiuk

The aim is to restore diverse, representative, regionally integrated and self-sustaining native ecological communities (to the extent that is possible in an urban setting) and in doing so, honour Whadjuk heritage.

It is hoped that by improving the condition of the bushlands, they will become better refuges and ecological linkages for biodiversity, while also helping to restore people’s relationship with nature and guaranteeing the enjoyment of these special places by future generations.

The inner-city Kings Park bushland (267 ha) has more than 80 restoration sites ranging from less than 1 ha to 40 ha.

Two significant restoration projects commenced in the late 1990’s: the WMC Resources – Mt Eliza Escarpment Restoration Project and the Alcoa – Kings Park Jarrah Tuart Restoration Project. Both were incredibly ambitious projects, with blankets of weeds being converted to native limestone heath on the steep and unstable slopes of Mt Eliza escarpment (Mooro Kaarta), and a former rubbish tip site being restored to eucalyptus - banksia woodland on the sandy plateau.

Since the early 2000’s, restoration sites have been progressively prioritised across Kings Park’s large plateau and this work is ongoing. The Friends of Kings Park Bushland Carers work alongside the Bushland team across a range of these sites.

Bold Park, which supports 437 ha of undulating woodlands, heaths and coastal dunes, has a greater diversity of ecological communities than Kings Park, but it also has more bushland in degraded condition. Accordingly, restoration is focused within nine main precincts that are larger than most of the Kings Park sites.

They include a 6 ha precinct of tuart - banksia woodland selected and actively restored by the Friends of Bold Park Bushland, as well as a precinct at Reabold Hill (a high point on the Swan Coastal Plain at 85 m with spectacular coastal and city views) and several areas of woodlands and heaths burnt by wildfire, the largest at 76 ha from a summer fire in 2000.

Restoration of urban bushlands comes with many challenges, including fragmentation, historic disturbances (including limestone quarrying, timber extraction and livestock grazing), ongoing invasion by weeds and pests, arson and accidental fires, and the impacts of recreation.

Science-based adaptive management is adopted and, while the specific activities undertaken at restoration sites vary depending on the causes and amount of degradation, physical and biological site characteristics and accessibility to the public, the overall approach is underpinned by a common set of key strategies.

These include avoiding native vegetation clearing, minimising disturbance and adhering to hygiene protocols, early detection and attempted eradication of new invasive species, the control of established priority weeds and pests, replanting of local native plants from propagules collected on site and providing habitat for fauna and fungi.

Ongoing monitoring of Kings Park and Bold Park bushlands shows that restoration has resulted in many improvements, but it is also clear that neither bushland has reached the point of self-sustainability.

Since restoration began, native plant abundance and species richness has increased in both bushlands which is an excellent outcome.

Shade cloth plant guards are used to protect young plants from rabbits in Bold Park. Tube stock planting is undertaken more often than direct seeding in Kings Park and Bold Park bushlands because it yields better establishment rates. It is also an enjoyable, hands-on activity for volunteers who want to get involved in the restoration process. Photo: Jason Thomas

Perennial Veldt Grass and woody weeds have declined across Kings Park and priority weeds such as Pelargonium, Geraldton Carnation and perennial Veldt Grass have declined in Bold Park’s restoration precincts. Veldt Grass is highly flammable and its reduction is an important component of the fire management program, with a current Fire Ecology research project demonstrating the importance of weed control following a fire to improve biodiversity outcomes and reduce bushfire risk.

But it is not all good news. The longterm decline in iconic resprouting banksias (B. attenuata and B. menziesii) in Kings Park is particularly concerning and a research project into causes of their decline has been undertaken and efforts are being made to increase replantings.

Many resprouting shrubs (plants with lignotubers) have also declined in both Kings Park and Bold Park and research into improving propagation success has recently commenced through financial support from the Friends of Kings Park Fund.

Weeds continue to be a major issue and their management accounts for the greatest proportion of restoration resources. To ensure effective use of resources, regular monitoring is used to prioritise weed threats and guide the weed control program.

The last decade was particularly tough for Perth’s bushlands, with declining rainfall and increasing temperatures, including one of the hottest summers on record over 2010 – 2011.

Two decades of work in Kings Park and Bold Park has shown that restoration can help push back against threatening processes, but interventions to reverse degradation are still very much needed, particularly given the drier and hotter conditions predicted for this region.

The current decade – the UN Decade on Ecosystem Restoration – is a critical moment to engage with Whadjuk people to listen and learn about healing country and to expand the science-based conservation and restoration effort across Perth’s bushland network.

Our unique biodiversity and our future generations depend on it.

Restoring Bold Park bushland

One of the larger restoration precincts in Bold Park (the Oceanic Precinct) takes in the west side of Zamia Trail but not the east side. The difference in condition between the restored (west) and unrestored (east) sides is immediately obvious to those who take a walk along the trail. A tuart - banksia canopy with scattered Zamias (Macrozamia fraseri) occur on both sides, but the understoreys are very different.

An aerial view showing an abundance of perennial Veldt Grass and other weeds such as Rose Pelargonium (Pelargonium capitatum) on the left (unrestored side) compared to dense native vegetation (with tube stock just visible) on the right (restored side). Photo: Ben Nuske

An understorey dominated by the highly invasive weed perennial Veldt Grass (Ehrharta calycina) on the unrestored side (east of Zamia Trail). Photo: Marty Brotherson

An understorey with a diverse range of native species on the restored side (west of Zamia Trail). Photo: Marty Brotherson

Restoring Mt Eliza escarpment

A significant restoration project on Kings Park’s Mt Eliza escarpment commenced in 1998 with initial financial support from WMC Resources, resulting in dramatic improvements to both the scarp’s stability and its native biodiversity. Historic disturbances from limestone quarrying, timber extraction, path construction and planting of exotic species all led to the geological instability and degradation of the scarp.

Prior to restoration, sites like this were common on the scarp, with an abundance of non-native pine trees (Pinus spp.), Century plant (Agave americana) and the highly invasive Bridal Creeper (Asparagus asparagoides), and very few native plant species. Photo: Ian McLean

Following the careful removal of large quantities of weeds, a range of bioengineering techniques were used to reduce the risk of erosion and rock fall. Here, jutemat had been laid on exposed slopes for temporary stabilisation, and a mix of native limestone heath species were being planted to provide long-term soil stabilisation following root development. Ropes and harnesses were used to ensure safety on a very steep slope. Photo: Tony Scalzo

Native limestone heath covers the slope in 2013, after 15 years of restoration. Photo: BGPA collection

Restoring a former tip site in Kings Park bushland

A former tip site, operating as the main area for rubbish disposal in Kings Park until 1990, was restored to eucalyptus - banksia woodland with support from Alcoa of Australia and Rocla Quarry Products (now Hanson Heidelberg Cement Group). Significant site works preceded revegetation, including refuse removal, levelling and deep ripping, removal of contaminated soil, infill with clean yellow sand and herbicide application.

The former tip prior to site works, showing soil bunds and heavy weed invasion. Photo: BGPA collection

In 1998, Banksia sessilis brush was laid in strips to improve soil conditions, and volunteers and staff joined together to plant native seedlings; direct seeding was undertaken shortly after. Photo: BGPA collection

The former tip site in 2021, after 23 years of restoration. Photo: Ryan Glowacki

The stats

5.7 million annual visitors to Kings Park and Bold Park

150 hectares under restoration

2200 hectares of Veldt Grass control in 20 years

200+ hectares of post-fire management since 2000

200 kilos of local native seed collected

1.24 million local native tube stock planted

617 volunteers have contributed 18,434 hours to bushland restoration since 1997