Kakadu National Park

Mining has long been viewed as one of the principal threats to the site and several reports about the uranium issue have been produced (World Heritage Committee, 1998; Environment Australia, 1999). Restoration of historic small-scale mining has been undertaken elsewhere in Kakadu (IUCN, 1992) and is ongoing in the south of the park (UNESCO, 2003; DNP, 2012). The Koongarra Project Area (1,228 ha), one of the three mining leases surrounded by the park, was added to the World Heritage site in 2011 (World Heritage Committee, 2011), following sustained advocacy from the senior Djok Traditional Owner and Australian environmental NGO’s.

Energy Resources of Australia’s Ranger uranium mine, situated on an excised statutory project area surrounded by Kakadu closed in 2021. A program of remediation and rehabilitation has begun that is guided by a comprehensive closure plan (Ranger Mine Closure Plan, 2023). The land is required to be rehabilitated back to a state in keeping with the adjacent park by January 2036. It remains uncertain whether this is possible in that time frame. Detailed rehabilitation planning, and remediation and revegetation works have been undertaken since the closure (IUCN Consultation, 2024). The major ongoing risk to the site from mining is leakage of contaminants from contained waste deposits. These are required by Australian federal law to be isolated from the wider environment for ‘not less than ten thousand years'. This risk is subject to supervision and regulation but as an untested scenario, confidence in the success of the rehabilitation of the Ranger uranium mine site must be tempered by the possibility of ongoing contamination of the National Park through leakage from the mine site, particularly the tailings storage facility (IUCN Consultation, 2020b). The Australian Government has committed to monitoring the ongoing contamination risk on the values of Kakadu from the Ranger mine, with a detailed supervision and monitoring regime working with the mine’s operators. Continuing current remediation works by Energy Resources Australia, and monitoring by the Office of the Supervising Scientist is essential to reducing the risk of leakage and localised contamination.

In 2019, the Australian Government committed AU$35 million towards the remediation of Jabiru township with a package of measures to shape the long-term future of the town (IUCN Consultation, 2024). Parks Australia and the Office of the Office of the Supervising Scientist have commenced a project to remediate the Koongarra site on behalf of the Director of National Parks in consultation with Traditional Owners. In 2024, the project received $2.2 million in funding from the Australian Government (IUCN Consultation, 2024). Given long term commitments to both the remediation work, and to the research that is required to evaluate remediation success or failure, important risks to manage are the funds and structures required for these tasks.

In 2024, a lease extension to Energy Resources Australia for the Jabiluka Project Area (7,300 ha) was refused, and this decision is currently under judicial review. The Australian Government and Mirarr Traditional Owners are working to seek incorporation of the Jabiluka Mineral Lease area into Kakadu National Park and the associated World Heritage property (IUCN Consultation, 2024).

Tourism in Kakadu provides a rare and essential source of income and employment for local communities. Tourism also contributes to the park’s operational budget. The closure of the Ranger Mine in 2021 brings changes to the Kakadu regional economy, with tourism needing to become the key sustainable economic base for local communities. Tourism in Kakadu is carefully managed to sensitively showcase the natural and cultural values to visitors, provide economic and employment opportunities for locals and improve management programs for threatening processes through increasing operational funds. Potential impacts of more tourism opportunities and higher visitor numbers include increasing the transmission of invasive species, increasing risk of fire, and damaging landscape values through more roads, infrastructure and waste. With tourism as a key economic driver for the local Traditional Owners, the potential impacts must be managed carefully into the future through the Australian Government’s Kakadu Management Plan and statutory environmental impact assessment processes. A Tourism Master Plan 2020-2030 has been prepared and is being implemented (Parks Australia, 2020).

In 2020-2021, tourism to the site (and any associated impacts) was severely curtailed due to international and national constraints imposed in response to the COVID-19 pandemic. Post-pandemic, visitor numbers have returned to pre-pandemic levels (IUCN Consultation, 2024). Improvements have been made to the way that the assessment team that administers the regulation of activities in the park, interacts with Northern Territory and Australian Government bodies responsible for building and maintaining tourism infrastructure. Environmental Impact Assessments are routinely submitted and reviewed by the park staff and receive approval from the appropriate authority. This has resulted in greater transparency and efficacy in the way that major works projects are managed in the park and has mitigated the impact of tourism overall (IUCN Consultation, 2024).

Although Kakadu currently has a low proportion of weeds, with less than 8% of the 700-plus plant species recorded in the park recognised as weeds, many of the park’s landscapes are being impacted by invasive weeds, some heavily impacted.

Highly invasive species such as annual and perennial mission grass occupy large areas of the north-east and central parts of the park and are likely to continue to spread in lowland woodland environments. These species cause a dramatic increase in the intensity of fire, and such weed-fuelled high-intensity fires may threaten many natural values. Climate change modelling for the tropical savannas indicates these impacts will worsen through grassy-weed fuelled fires under warmer temperatures (DNP, 2017).

Since 2020, targeted action against gamba grass in Kakadu has been delivered through a collaboration between a local Natural Resource Management group and Djurrubu Rangers - an on-Park Indigenous ranger group - and through the preparation and implementation of the recent ‘Gamba Grass Eradication Plan 2023-2026’, with a AU$4 million grant funding committed through the ‘Threatened Species Action Plan 2022-2032’. Additional funding from the Australian Government to support development and implementation of the gamba grass eradication plan is welcome and will help to ensure the gamba threat to Kakadu is managed, with benefits for the management of other grassy weeds, especially the mission grasses.

Aquatic grassy weeds such as para grass and olive hymenachne occur on wetland and floodplain areas and have the potential to invade and alter vast areas. Salvinia is spreading in wetland environments and is now present in the Yellow Water visitor area and adjacent waterways used for recreational fishing. Although mimosa is largely under control due to significant effort over many years, it remains an ever-present threat to floodplain areas (DNP, 2017), with plants persisting, and seeding detected in some locations in 2022 (IUCN Consultation, 2024).

Many of these weed species can outcompete native plants, transform vegetation structure and dynamics, deplete soil nutrients, affect food and shelter resources for native animals, reduce the traditional foods of Indigenous people 'bush tucker' (Adams et al., 2018), and compound fire impacts through fuelling fires of increased intensity and frequency (Rossiter et al., 2003; Rossiter-Rachor et al., 2009; Setterfield et al., 2010, 2013; Adams and Setterfield, 2013; Ens et al., 2015). The weed west indian pinkroot (Spigelia anthelmia) was recorded for the first time in Australia in 2019, in the Ranger mine area (Supervising Scientist 2019), and has potential to cause significant impact in Kakadu. Therefore while weeds in the park are generally well managed (Adams et al., 2015), the highly invasive nature of some species and the cost of managing them over such a vast area, means the threat to World Heritage values of invasive plant species remains high.

In managing weeds in the park, general activity permits issued for miscellaneous works contain standard conditions aimed at mitigating the risk of weed introduction and spread. Special conditions are attached to higher-risk activities (such as importing earth material or plants from outside the park) that include the need for certification that imported materials are weed-free. Where possible, earth material and plants are sourced from within the park. Furthermore, a decommissioned wash-down bay at the north entrance to the park is planned to be replaced in the forthcoming precinct upgrades (IUCN Consultation, 2024).

Weeds, fire, feral animals, and climate change will all interact to impact the natural and cultural values of Kakadu National Park. Therefore weed management, fire management, feral animal control, and mitigating the impacts of climate change must all be addressed coherently with management actions integrated across all aspects of park management.

Fire management in the park occurs in consultation and conjunction with the Binninj/Mungguy people who have managed Kakadu for generations. Active and strategic management of fire in Kakadu's sandstone environments (and by managers in adjacent Indigenous Protected Areas) has resulted in improvemed fire regimes, with a reduced incidence of extensive and high intensity fires in this 'stone country' (Murphy et al., 2015).

The 2022 - 2024 prescribed burning seasons saw a continuation of high numbers of Traditional Owners employed in fire management in the park, with most engaged in ground burning; and the highest number (27) of Traditional Owners involved in aerial burning in the 2024 season (data from Kakadu annual fire reports, IUCN Consultation, 2024).

Adding to the single fire officer role in 2023 were two new ongoing positions (fire manager and fire officer) as well as three seasonal fire coordinator roles to build a ‘fire team’. This has increased Traditional Owner engagement in fire management and improved coordination and communication.

In lowland wetlands, the cessation of traditional Indigenous floodplain burning practices in the past (McGregor et al., 2010), is thought likely to have contributed to the widespread increase in aquatic grasses and in particular the invasive para grass, on the floodplain (Bayliss et al., 2006). In more recent times, there have been efforts to reintroduce traditional fire management to areas such as the Kakadu wetlands (MacGregor et al., 2010). The decline of the small mammal fauna in the Kakadu National Park and elsewhere in northern Australia has been attributed, at least in part, to an increase in widespread and intense late season wildfires and consequent decline in the area of longer-unburnt habitat (that supports greater vegetation structural diversity, more shelter sites (e.g. hollow logs) and provides more fruit and other resources) (Woinarski et al., 2001, 2004, 2010; Griffiths et al., 2015; Lawes et al., 2015). There is now also strong evidence of the impacts of fire compounding impacts of feral cats as a threat to native mammals and many other species (McGregor et al., 2014, 2016; Woinarski et al., 2019); and most of Kakadu's threatened and declining mammals have preferences for less frequent and less severe fires than those prevailing more recently (Woinarski and Winderlich, 2014).
When carefully and skilfully managed, fire is potentially the park’s best landscape-scale management tool. A strategic burning program has been in place in the park since 2016 to carry out extensive prescribed burns in the early dry season, and some prescribed burning in the wet season. This creates mosaics of burnt and unburnt vegetation, reduced fuel along roadsides and other easily accessible areas, and creates a network of and firebreaks that help to reduce the extent and therefore damage of late season fires. The program has had success in reducing the extent and severity of fire in the park (DNP Annual Report, 2019-20), which should create conditions to support the recovery of species.

In contrast to 2019 which saw extensive fires in the park, in 2021-2023 there was a reduction in the overall proportion of the park burnt compared to previous years (KNP fire data, IUCN Consultation, 2024). A prescribed burning program in the wet season has been implemented annually since 2021 to remove grassy fuel and has contributed to a finer-scale mosaic of fire histories across the Park. In 2024, the National Environmental Science Program funded an important multi-year research program on wet season burning to better understand traditional knowledge of wet season burning and inform the production of best-practice methods, and application of this to management approaches. Despite sustained fire management during the reporting period, challenges remain.

The extent of longer-unburnt (3+ years since fire, 5+ years since fire, 10+ years since fire) habitat, a critical resource for many of the site's threatened, endemic and relict species, has not increased during the reporting period (KNP annual fire data). Longer-unburnt (3+ years since fire) habitat, has been less than 10% of the lowland woodlands from 2020-2023: far less than the 25% recommended, for example, for maintenance of bird assemblages in the region (Woinarski and Legge, 2013). The habitat requirements of many of the site's threatened and endemic species, and the fire regimes that they depend upon, are not being met.

Some of the best results in fire management in the history of the park were achieved in the period 2016-2018 inclusive due to the large scale, highly detailed and strategic program and, it is hoped that this programme will lead to the recovery of many species (IUCN Consultation, 2020a). Overall fire regimes in the Stone Country have been demonstrated to be in a more benign state now than at any time over the last three decades, most likely due to extensive use of prescribed burning (Murphy et al 2015; Evans and Russell-Smith, 2020). Similarly, while ongoing challenges remain, numerous other improvements have been made over the life of the park (Russell-smith et al., 2017).

Unplanned, destructive fires, and high fire frequency, remains a critical driver of environmental impact on the natural and cultural values of the park. Management of fire regimes, incorporation of cultural values and strategies into fire management, and adequate resourcing of fire management practices are critical to maintaining the park's world heritage values. Fire, feral animals, weeds and climate change will all interact to impact the natural and cultural values of Kakadu National Park. Therefore fire management, weed management, feral animal control, and mitigating the impacts of climate change must all be addressed coherently with management actions integrated across all aspects of park management.

The management objective for invasive animals in Kakadu is to limit, as far as possible, their adverse effects on the environment while taking into account the views and economic interests of its Aboriginal Traditional Owners.

Invasive animals in the World Heritage site include Asian water (swamp) buffalo (Bubalus bubalis), cattle (Bos indicus & B. taurus), pigs (Sus scrofa), horses (Equus caballus), donkeys (Equus asinus), cats (Felis catus), dogs (Canis familiaris), rats (Rattus rattus), mice (Mus musculus), house geckos (Hemidactylus frenatus) and European bees (Apis mellifera). Cane toads (Rhinella marina) spread to Kakadu (from an Australian introduction in north-eastern Queensland), arriving at the site for the first time in early 2001, and subsequently became established across the site in large numbers. Their establishment has caused severe declines in Kakadu and elsewhere of many native predators (because of the toad's toxin), including northern quoll (Dasyurus hallucatus), Mitchell's water monitor (Varanus mitchelli), Merten's water monitor (Varanus mertensi), and plains death adder (Acanthophis hawkei) (Doody et al. 2009, 2015; Phillips et al. 2010; Woinarski & Winderlich 2014). These three reptile species are now listed by the IUCN as threatened because of this severe decline. Mitchell's water monitors are listed as critically endangered (Shea et al., 2018) and Merten's water monitors are listed as Endangered (Shea et al., 2018). Nevertheless, populations of toad-vulnerable predators are persisting in the park, with evidence that populations of some of these toad-susceptible native species have begun to recover from the impacts of cane toads with more frequent sightings of Floodplains monitor and northern quoll in some areas (IUCN Consultation, 2024).

For at least some invasive introduced animal species, there has been no substantial and enduring reductions in population sizes and distributional extent (and hence impact) in the site over recent decades. Some introduced pest species (such as feral cats) probably occur ubiquitously across the site, other than on the small offshore islands. Predation by feral cats, operating interactively with the effects of extensive fires on habitat conditions, is a significant threatening process (Department of the Environment 2015; Ziembicki et al., 2015; Stokeld et al. 2018; Murphy et al. 2019), contributing to the decline of many of the site's native mammals, including the probable recent extirpations from the site of some native mammal species such as brush-tailed rabbit-rat (Conilurus penicillatus).
The park managers are undertaking a trial of different methods for feral cat management including a trial of cat grooming traps (FELIXER) in non-lethal mode in 2022-2023, but these efforts have not yet resulted in any sustained reduction of this major threat (IUCN Consultation, 2024).

Feral pigs are now widespread across the site. Their impacts are diverse. They forage extensively on the corms of sedges (primarily Eleocharis dulcis), competing directly with waterbirds such as magpie geese (Anseranas semipalmata) and brolgas (Antigone rubicunda), for which this is a key food resource (Bayliss et al., 2006, Pettit et al. 2011). But pigs are also major predators of (and a significant threat to) aestivating freshwater turtles (Fordham et al. 2006, 2007), many native yams and ground-nesting birds. A study by Stobo-Wilson et al. (2020) indicates that the impact of feral herbivores such as buffaloes, horses, cattle and donkeys on habitat and native species has been largely underestimated.

In 2022, landscape-level feral pig control (aerial culling) was reinstated, and over 10,000 pigs were culled in the northern half of the park, with activities aligned to an important site for the threatened Alligator Rivers yellow chat (IUCN Consultation, 2024).
In 2022, water buffalo, horses and donkeys were also removed from some areas of the park. In 2024 feral pig control (aerial culling) continued in some focal areas including coastal floodplains and vulnerable wetland areas. In 2021, a drone-based annual monitoring program was developed to map and measure feral pig impacts on floodplains to accurately assess the effectiveness of feral pig culling on environmental health (IUCN Consultation, 2024). In 2024, a park wide feral herbivore and pig aerial survey was completed, to inform the preparation of an updated feral animal strategy. From 2022-2024, park staff have been trained in the application of a range of feral animal trapping methods, with successful use of baited traps for small scale feral pig control. Recent successful control activities have resulted from substantial clan-based consultation and agreements on target species and densities.
In 2017, a feral animal working group, made up of Kakadu Traditional Owners, developed a set of feral animal management protocols. These protocols set out the ways in which feral animals are managed in Kakadu, including provisions for economic opportunities for Bininj/Mungguy.

Through a collaborative project with the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Traditional Owners in the south of the park have begun a project co-designing a monitoring program to assess feral animal impacts at waterholes (IUCN Consultation, 2024). In 2023, the Kakadu Board of Management approved a 3-year mustering permit in the south of the park – due to commence in 2025 - with the aim of reducing densities of water buffalo and cattle while providing economic benefits to Traditional Owners. This program builds on other industries that provide Traditional Owner livelihood opportunities in reducing feral animals numbers, such as pet-meating businesses (IUCN Consultation, 2024).

Kakadu has been the site of on-ground research to collect data on gaseous exchange data from feral animal damaged floodplains and wetlands to inform the development of a carbon abatement scheme (blue carbon) centred around feral ungulate (buffalo, cattle) removal. Implementation of this approach may provide economic incentives that lead to income for Traditional Owners when reducing densities of feral herbivores in the park (IUCN Consultation, 2024).

Management of invasive species and developing programs that integrate cultural values for landscape, conservation and economic security requires adequate resourcing. Management of invasive species as a whole is critical to maintaining the park's world heritage values. Feral animals, fire, weeds and climate change will all interact to impact the natural and cultural values of Kakadu National Park. Therefore feral animal control, fire management, weed management, and mitigating the impacts of climate change must all be addressed coherently with management actions integrated across all aspects of park management.

It has been hypothesised that increasing levels of CO2 in the atmosphere is favouring woody plant growth to the detriment of treeless floodplains, important habitat for numerous species and migratory waterfowl (Bowman et al., 2008). While other factors could also be causing woody encroachment, this rapid environmental shift could be a threat to a number of values of the World Heritage site.

Climate change is already affecting the natural values of Kakadu and it will affect all natural and many cultural World Heritage values in the site. Effects of climate change are already evident, and these impacts will be magnified in the coming decades.

Changes to salt and freshwater wetlands through saltwater intrusion have been observed in the park over the past few decades (Hyder, 2008). Saltwater intrusion can lead to the conversion of freshwater paperbark (Melaleuca spp.) swamps and other floodplain vegetation communities into extensions of the mangrove margin. Dieback of some Melaleuca (Bowman et al., 2010) and the extension of mangrove species (Asbridge et al., 2019) has been observed in Kakadu’s northern wetlands. Saltwater intrusion will increasingly cause major changes in the composition, productivity, ecological dynamics and values of the site's significant lowland wetland assemblages (Stephenson et al., 2018).

Extreme weather events have recently caused large scale losses of mangroves within the site and in the broader region (Asbridge et al., 2019; Duke et al., 2017). In 2021, Parks Australia ran a climate change vulnerability workshop in Kakadu with Bininj/Mungguy, park staff and other participants. A vulnerability assessment report was prepared (IUCN Consultation, 2024).

Park managers are implementing a climate change strategy that includes a range of adaptation, mitigation and communication actions to manage the anticipated changes. A challenge identified in 2003 is whether management will be able to cope with unpredictable changes in temperature, storm frequency, flooding, drought and changes in sea water composition to conserve the World Heritage values (UNESCO, 2003) – the strategy adopted in Kakadu is the adoption of management practices that maximise ecological resilience to increase capacity to adapt as climate change manifests (DNP, 2017).

In late-2024, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) with funding from the National Environmental Science Program's Climate Systems Hub, commenced a multi-year project to prepare an adaptation plan for Kakadu by applying the Climate Change Toolkit for World Heritage Properties in Australia. This work will heavily engage parks staff, Traditional Owners (Bininj/Mungguy) and the community to guide planning decisions over the next decade (IUCN Consultation, 2024).

Climate change is often referred to as a threat-multiplier. In Kakadu climate change will increase the impacts of feral animals, destructive fires, change to wetlands, species loss, and it is likely to reduce habitat resilience.

Climate change should not be seen or managed in isolation from other threats such as fire or feral animal impacts, because those impacts will also increase the effects of climate change. All threats to the natural and cultural values of the site must be managed together, and not in isolation. This requires adequate and integrated planning, and the resources necessary to achieve positive outcomes.