Biodiversity

Introduction

This section provides an assessment of biodiversity in the ACT, including threatened and important species, conservation of ecosystems and species, native vegetation, and invasive plants and animals. The following indicators are assessed:

• B1: Threatened species and ecological communities
• B2: Extent and condition of conservation areas
• B3: Representation of threatened species and ecological communities in conservation areas
• B4: Extent and condition of native vegetation
• B5: Distribution and abundance of terrestrial invasive plants and animals

For background information on biodiversity in the ACT see Background: Biodiversity. 

Biodiversity is also discussed in Climate change, Water, and Fire. The impacts of the Orroral Valley bushfire on the ACT’s biodiversity is also discussed in 4. Bushfires in the ACT.

Key findings

Key actions

That the ACT Government: 

Indicator assessments

Data summaries

General

• The main pressures on biodiversity in the ACT are climate change, invasive plants and animals, vegetation loss, habitat fragmentation, changes to the frequency and intensity of fire, and land use change (particularly greenfield development).

Threatened species and ecological communities

• In 2023, a total of 58 species of fauna and flora (terrestrial and aquatic) were listed as threatened under the Nature Conservation Act 2014.
• These species include eight critically endangered, 21 endangered, 28 vulnerable and one regionally conservation dependent.
• From 2019–20 to 2022–23, six additional species were listed as threatened, three species were given a higher threat status and only one species was given a lower threat status.
• There are three ecological communities listed as threatened in the ACT: Natural Temperate Grassland (Critically Endangered), Yellow Box/Red Gum Grassy Woodland (Critically Endangered), and High Country Bogs and Associated Fens (Endangered).
• There are two key threatening processes listed in the ACT: the Loss of Mature Native Trees (including hollow-bearing trees) and the Unnatural Fragmentation of Habitats which was listed in December 2019.

Conservation

Extent of conservation areas

• In 2023, there were around 146,800 hectares of conservation areas in the ACT, protecting over 60% of the total ACT area. This not only represents a significant proportion of the ACT’s natural environment but is also a much higher proportion than any other jurisdiction in Australia.
• Namadgi National Park and Bimberi Wilderness Area account for over 75% of the conservation area and around 47% of the total area of the ACT. Nature reserves (including Canberra Nature Park) account for around 14% of the conservation estate, water supply 4% and special purpose reserves around 6%.
• From 2019–20 to 2022–23, around 670 hectares were added to nature conservation areas in the ACT.
• No new offset areas were created from 2019–20 to 2022–23 with the area remaining at around 1,865 hectares, including 870 hectares protected by nature reserve.

Condition of conservation areas

• It is not currently possible to determine the condition of conservation areas in the ACT.
• Assessments have been undertaken for selected ecosystem types as part of the ACT Government’s Conservation Effectiveness Monitoring Program. Results show that aquatic and riparian ecosystems, bogs and fens, and lowland grasslands are in poor condition compared to a reference (or pre-European) state, but in moderate condition compared to management goals. Upland grasslands were found to be in good condition.
• It is also not currently possible to assess whether offsets have ensured no net loss of biodiversity following land development. Assessments for offsets will likely take many years, particularly given that management interventions need to be undertaken over long periods of time to attain the desired ecosystem and biodiversity outcomes.
• Climate change will continue to threaten conservation areas, especially where changes to temperature and rainfall, and the occurrence of fire, exceed the tolerances of ecosystems.

Representation of threatened fauna in conservation areas

• Species that have all, or close to all, of their known and potential habitat in ACT reserve areas include the Northern Corroboree Frog (Pseudophryne pengilleyi), Broad-toothed Rat (Mastacomys fuscus mordicus), Smoky Mouse (Pseudomys fumeus) and Southern Greater Glider (Petauroides volans). The Pink-tailed Worm-lizard (Aprasia parapulchella) also has around 82% of its known and potential habitat in reserve areas.
• Around a third of Key’s Matchstick Grasshopper (Keyacris scurra) and Spotted-tailed Quoll (Dasyurus maculatus maculatus) habitat is not reserved. The Golden Sun Moth (Synemon plana) and Perunga Grasshopper (Perunga ochracea) also have around 20% of their habitats outside of reserve areas.
• Several species have large areas of habitat on National Land including 50% for the Grey-headed Flying Fox (Pteropus poliocephalus), 42% for the Grassland Earless Dragon (Tympanocryptis lineata), 28% for the Golden Sun Moth, 28% for the Perunga Grasshopper and 22% for the Striped Legless Lizard (Delma impar).
• For species with large proportions of non-reserved habitat, this is due to their dependence on grassland and woodland habitats which are not as well protected in conservation areas as other ecosystems such as forests.
• Some of the ACT’s threatened species only occur in managed sanctuaries, including: the Eastern Quoll (Dasyurus viverrinus), New Holland Mouse (Pseudomys novaehollandiae), Eastern Bettong (Bettongia gaimardi), Southern Brown Bandicoot (Isoodon obesulus obesulus), Brush-tailed Rock-wallaby (Petrogale penicillate), and Koala (Phascolarctos cinereus). This means that 100% of their known habitats are in managed reserves.
• Four of the ACT’s threatened aquatic species have around 90% to 100% of their potential distribution in ACT conservation areas, including the Two-spined Blackfish (Gadopsis bispinosus), Trout Cod (Maccullochella macquariensis), Macquarie Perch (Macquaria australasica) and the Murray River Crayfish (Euastacus armatus). Silver Perch (Bidyanus bidyanus) has no wild distribution in the ACT.

Representation of threatened flora in conservation areas

• Over 60% of the known threatened plant sites in the ACT are located in reserves or on other land managed by the ACT Parks and Conservation Service. An additional 13% occur on national land, which is managed by the National Capital Authority, and 22% occur on non-reserved lands in areas such as urban open space, road reserves, railway reserves and cemeteries.
• Seven of the ACT’s 13 threatened flora species have all or most of their locations in reserves. However, there are five species with a substantial proportion of known locations outside ACT reserve areas, including Black Gum (Eucalyptus aggregata), Small Purple Pea (Swainsona recta), Canberra Spider Orchid (Caladenia actensis), Button Wrinklewort (Rutidosis leptorrhynchoides) and Murrumbidgee Bossiaea (Bossaiea grayi). The Tarengo Leek Orchid (Prasophyllum petilum) only occurs at Hall cemetery.

Representation of threatened ecological communities in conservation areas

• Of the three ecological communities listed as endangered in the ACT, the High Country Bogs and Associated Fens community is the most fully protected in ACT reserve areas.
• For Natural Temperate Grassland, whilst 100% of upland grasslands are within reserve areas, only 60% of lowland grasslands are in ACT conservation areas with another 28% on National Land and around 11% on non-reserved land.
• Yellow Box/Red Gum Grassy Woodland has 77% of its representation on ACT reserved land. This has increased significantly since 2019 due to the inclusion of secondary grassland in area assessments, rather than actual changes in reserve extent. Another 22% of Yellow Box/Red Gum Grassy Woodland are on National Land.

Representation of vegetation classes and communities in conservation areas

• The vegetation class most underrepresented in the reserve system is Southern Tableland Grassy Woodlands which only has 36% of its extent protected — a 5% increase from 2019 due to the creation of additional reserve areas.
• Other vegetation classes underrepresented in the reserve system include Upper Riverina Dry Sclerophyll Forests (63% protected in reserves) and Tableland Clay Grassy Woodlands (69% protected in reserves).
• The least protected vegetation communities in the ACT are woodland, grassland and open forest communities.
• There were increases in the reserved area for four of the least protected vegetation communities between 2019 and 2023, including Red Box tall grass-shrub woodlands (increase from 21% to 41% reserved), native grassland (21% to 37%), Yellow Box – Apple Box tall grassy woodland (30% to 39%) and Snow Gum grassy mid-high woodland (23% to 30%). Although the increases were mostly small and still leave much of these communities unprotected, they are important to help protect these vegetation communities in the future.

Native vegetation

Extent

• It was not possible to determine changes in the extent of native vegetation over the reporting period. This was also found to be the case for the 2015 and 2019 ACT State of the Environment reports which noted the lack of comprehensive documented information on vegetation loss. The cumulative impact of approved vegetation clearing has also not been documented or assessed.
• Most of the ACT’s current native vegetation losses are from urban development and from environmental pressures such as climate change, bushfires and dieback.
• Between 2015 and 2020, 14,455 mature native trees were lost across urban Canberra, a 6.2% decrease. These trees are critical for many fauna species.
• Between 2019 and 2023, revegetation in the ACT included 28,000 trees and shrubs planted in the Lower Cotter Catchment, a further 2,940 planted in the Stony Creek Nature Reserve, and 3,500 planted in the Murrumbidgee River Corridor. In addition, 40 hectares of revegetation was undertaken on rural land in 2022.

Condition

• It was not possible to determine changes in the condition of all native vegetation over the reporting period. This was also found to be the case for the 2015 and 2019 ACT State of the Environment reports which noted a lack of comprehensive documented information on the condition of vegetation in the ACT.
• As a result of the 2003 and 2020 bushfires in the ACT, only 18% of assessed native vegetation in 2023 was found to be within the required tolerable fire interval, 62% was below minimum tolerable fire interval (fire interval too short to maintain vegetation in its optimal state), 14% above the maximum tolerable fire interval (fire interval too long) and 6% was classed as long unburnt.
• Bushfires have also meant that the Juvenile growth stage is the most common for the ACT’s native vegetation, accounting for 35% of the total assessed communities. The Adolescent growth stage accounted for 27% of assessed native vegetation, with Mature at 18% and the Senescent growth stage at 20%. While all growth stages are represented across the ACT, 62% of assessed vegetation is dominated by the younger Juvenile and Adolescent growth stages.
• The dominance of early and young growth stages in the ACT has significant implications for biodiversity, especially for fauna that require the habitat features of older growth stages including established overstorey canopies, deep litter layers and tree hollows.
• Climate change has led to an increased occurrence of tree dieback in the ACT, particularly for Blakely’s Red Gum (Eucalyptus blakelyi) and subalpine snow gums (Eucalyptus debeuzevillei and Eucalyptus niphophila) in the Brindabellas.
• The Unnatural Fragmentation of Habitats was listed in 2019 as a key threatening process in the ACT. Despite this, comprehensive information on the status and trends of vegetation and habitat fragmentation in the ACT was not available for this report.

Invasive plants and animals

• Invasive plant and animal species continue to pose a major threat to biodiversity, ecosystem health, primary production, social amenity and human health.
• Data on management outcomes clearly demonstrates the value of invasive species management to control established populations and to eradicate new outbreaks where possible.
• Management results also show the risk of invasive plant and animal populations re-establishing themselves in the absence of ongoing control.

Invasive plants

• In 2019, there were an estimated 700 introduced plant species in the ACT, 79 of which were introduced from elsewhere in Australia. In 2022–23, there were 28 new and emerging invasive plants identified as posing a threat to native ecosystems.
• From 2019–20 to 2022–23, nearly 35,000 hectares of invasive plant control was undertaken in the ACT for the ten most extensively managed invasive plant species. African Lovegrass accounted for the largest area treated at over 7,000 hectares, followed by Serrated Tussock (over 6,500 hectares), and St. John’s Wort (5,800 hectares).

Invasive animals

• It was not possible to comprehensively determine the distribution and abundance of invasive animals in the ACT for this report.
• There are an estimated 64 introduced vertebrate animal species in the ACT including 17 mammals, 33 birds, two lizards, one frog and 11 fish.
• The invasive animal species of most concern for the protection of the ACT’s native ecosystems and biodiversity are feral pigs, deer, foxes, rabbits and horses.
• Rabbit control is the most common management undertaken, occurring in all but one of the ACT’s reserves. Ongoing control has been effective in reducing the densities of rabbits by around 90% in areas of Canberra Nature Park and Namadgi National Park.
• Annual Eastern Grey Kangaroo culls are undertaken to protect the ACT’s grassy ecosystems from overgrazing. Between 2009 and 2022, over 24,000 kangaroos were culled.
• From 2019–20 to 2022–23, kangaroo culling numbers reduced across many sites. This is because of the effectiveness of previous kangaroo management and in response to higher sustainable kangaroo densities due to increased rainfall since 2020.
• The use of fertility control was incorporated into the kangaroo management program for the first time in 2022 with the aim of limiting population growth and reducing the need for future culling.

Management of biodiversity in the ACT

Context

The ACT has a large body of policies, strategies and plans whose explicit aim is nature conservation. These include well over 100 action and management plans for species and communities, conservation strategies and advice, reserve management plans and Activities Declarations. In spite of this substantial effort, threatened species and habitats continue to decline and new species are being listed as threatened (six new species have been declared threatened in the ACT in this reporting period).

However, rather than being an area of policy failure, this dispiriting result is largely due to broader anthropogenic pressures which are beyond the scope of conservation management. These pressures include climate change, bushfires, urban development and invasive species. This situation illustrates the fact that nature conservation policy cannot be the sole mechanism for preserving the ACT’s biodiversity when there are other policies actively working in conflict with its outcomes.

While this section specifically considers policies and legislation which seek to protect the ACT’s natural biodiversity, it must be recognised that a raft of other policy areas, such as planning, regulation and management of land use, have a direct impact — typically a detrimental one — on the achievement of conservation outcomes at the local and regional level. National and international inaction on climate change also makes it difficult for ACT conservation policies to accomplish their objectives.

Policy framework

The primary piece of legislation for biodiversity conservation in the ACT is the Nature Conservation Act 2014, which legislates the protection of native flora and fauna in the ACT and allows for the declaration of threatened ecological communities and species and preparation of reserve management plans for conservation areas. It covers a number of strategies, plans and other statutory instruments, some of which are outlined below.

The Nature Conservation Strategy 2013–23 sits beneath the Act and aims to guide a coordinated and integrated approach to nature conservation. Its vision for nature conservation in the ACT is “biodiversity rich, resilient landscapes stretching from the inner city to the mountains, where well-functioning ecosystems can meet the needs of people and the environment”. It aims to strengthen connectivity, resilience and community capability to build the adaptive capacity of natural ecosystems and people to a changing climate. It identifies both key environmental values and the major threats they are facing. The Nature Conservation Strategy 2013–23 has been delivered through successive five-year implementation plans which provide an effective way of building ongoing adaptation into delivery.

The Aquatic and Riparian Conservation Strategy and Action Plans 2018 provides guidance on the conservation of aquatic and riparian areas and component species. It focuses on reserved areas, particularly where threatened species occur, and therefore does not apply to urban waterways. The Aquatic and Riparian Conservation Strategy and Action Plans 2018 includes recommendations to address a range of key threats to aquatic and riparian species and ecosystems as well as action plans for threatened aquatic species. The management and enhancement strategies identified within it aim to increase the resilience of aquatic and riparian areas to threats such as climate change.

The Invasive Plants Operations Plan 2020–25 guides the management of weeds in the ACT. Its goals are to prevent invasive plant entry into the ACT; quickly find, contain, and eradicate any new incursions; and effectively minimise the impacts of widespread invasive plants. It provides a framework for prioritising species and areas for targeted management, and explicitly acknowledges the limited resources available for effective management. In addition, the Invasive Plants Operations Plan 2020–25 recognises the varying impacts of different weeds and the different management approaches required to successfully manage each species.

The ACT Pest Animal Management Strategy 2012–2022 has set the framework and approach for managing the undesirable social, environmental, and economic impacts of pest animals across conservation, rural and urban lands in the ACT. The ACT Pest Animal Management Strategy 2012-22 aims to prevent incursions by new animal species, reduce impact on native animals, and ensure the community is engaged in pest animal management.

The Eastern Grey Kangaroo: Controlled Native Species Management Plan 2017 sets out the approach for maintaining wild populations of eastern grey kangaroos in the ACT while managing their environmental, economic, and social impacts and ensuring their welfare.

Reserve management plans are prepared for reserves in the ACT under the Nature Conservation Act 2014. The Canberra Nature Park Reserve Management Plan 2021 encompasses management for the 39 nature reserves within Canberra which contain distinctive threatened ecosystems and species, landscapes and cultural heritage. This plan highlights the significant values present in the reserves and provides guidance on appropriate reserve use for various activities as well as the goals, objectives, policies and actions for management over 10 years to 2031.

Management plans for other nature reserves, and action plans for each of the ACT’s threatened species and communities, are also in place. All of the strategies and plans described above are within the purview of the Nature Conservation Act 2014.

The Water Resources Act 2007 aims to ensure that management and use of the water resources of the Territory sustain the physical, economic and social wellbeing of the people of the ACT while protecting the ecosystems that depend on those resources. It also aims to protect aquatic ecosystems and aquifers from damage and, if practicable, to reverse existing damage. The Water Resources Act 2007 enshrines the Environmental Flow Guidelines 2019, which set out the flow requirements needed to maintain aquatic ecosystems. Other water related policy in the ACT includes the ACT Water Strategy 2014–2044 and the ACT and Region Catchment Strategy 2016–2046.

Other pieces of legislation, notably the Planning Act 2023, Heritage Act 2004 and Environment Protection Act 1997, also contain elements which relate to the conservation of biodiversity in the ACT.

Policy effectiveness

Measuring changes in the environment or in the population of a particular species over time is challenging. The resources required to develop a reliable monitoring program can be prohibitive, particularly for rare and cryptic species. A full understanding of population changes also requires a substantial dataset to demonstrate trends over the long term, rather than showing short-term responses to particularly favourable or unfavourable conditions or to extreme events such as fire, flood and drought. Even when positive trends are detected (e.g. increase in threatened species or decrease in feral pests), it is often not possible to tell whether this is due to management activities or to broader environmental factors. Because of this, it is very difficult to determine whether changes in ecosystem health and species abundance are attributable to conservation policy in the ACT.

This section will provide commentary on shortcomings of the ACT’s policy framework to manage specific issues within the nature conservation policy suite based in part on the findings of the Alluvium Policy Review. The planned 2024 review of the Nature Conservation Act 2014 should afford some opportunity to address identified anomalies, but changes will also need to be made to other Acts to ensure that nature conservation legislation in the ACT is truly effective.

Protected areas

As noted above, a central premise of biodiversity protection is the allocation of areas for nature conservation and rehabilitation through land planning frameworks. The ACT has an impressive reserve network with over 60% of its land area in reserves of some kind. While reserved lands are likely to play a critical role in nature conservation in the ACT, the Policy Review highlighted that the ecological condition of most reserves in the ACT is unknown. It is therefore not possible to determine how effective the reserve network is in fulfilling its conservation objectives.

In Australia, European settlement has introduced a range of invasive animals and plants that significantly weaken the protection offered by a reserve. These invasive species, together with a range of other human disturbances, are likely to be exacerbated by urban expansion and population growth (refer to Urban Boundary). In addition to this, changes in vegetation and disturbance regimes (fire, drought and flood) associated with climate change mean that significant management and policy interventions are needed to control threats within the reserve network.

In the ACT, a number of legislative and practical aspects of reserve management make it challenging for threats to the natural values of protected areas to be managed effectively.

Perhaps most significantly, the Nature Conservation Act 2014 does not have ‘primacy’ in reserves, which is a crucial requirement for the long-term protection and preservation of reserved areas. Primacy in the interests of conservation should require that the relevant park management act serves to exclude other potentially conflicting legislation in reserves, or that the other legislation excludes itself from reserves. For example, in Tasmania the National Parks and Reserves Management Act 2002 explicitly provides for pre-eminence of the Nature Conservation Act 2002 within reserves, stating “A statutory power may not be exercised in relation to any land in a national park, State reserve, nature reserve, historic site or game reserve except where – (a) the exercise of the power is authorised by the management plan for that land; or (b) the power is a power under the Nature Conservation Act 2002”. Conversely, in the ACT several important aspects of land management including fire management, littering and dumping, domestic animal management (including animal/carer behaviour) and erection of structures are covered by a range of legislation that cannot be enforced by Parks and Conservation Service staff. This means that offences in these categories are generally not pursued in reserves, which, perversely, is where they should be most actively pursued in the interests of conservation.

Another area where the ACT’s nature conservation legislation departs from the usual practice in other Australian jurisdictions is in the legislation governing the designation of reserves. The Planning Act 2023 is the instrument which provides for reservation of land for a specific purpose (including wilderness areas, national parks, and nature reserves) and the management objectives for those areas. It also defines the mechanism by which reserve management plans are prepared. Siting of the responsibility for reserve gazettal in the planning area seems less than ideal since this area does not include staff positions where there is a requirement for expertise in nature conservation. While the Planning Act 2023 makes provisions for the Conservator of Flora and Fauna to provide input into decisions relating to reserves, the current administrative arrangements where the Conservator of Flora and Fauna sits within the structure of EPSDD and reports to the Director-General EPSDD (who also holds the position of Chief Planner) means that decision-making in relation to such matters is opaque.

While reserves are generally the preferred mechanism for protecting threatened species and habitats, unreserved land, including in urban areas, is likely to play an increasingly important role in biodiversity conservation. As the ACT moves into a future increasingly affected by climate change it seems unavoidable that some vulnerable species will not be able to survive in the region due to climatic factors wholly outside the control of the ACT Government. This is not a reason to abandon threatened species conservation, but overall biodiversity is very likely to decrease in the near future and protection of all surviving native habitat will be important.

Finally, the focus on human use of reserves — even within plans and policies dedicated to nature conservation — has the potential to engender negative impacts on areas or values that would benefit from restricted human access or which are not recognised as having value by the general public. An example of this is the allowance of dogs in nature reserves; this is prohibited under the Nature Conservation Act 2014 but permitted in many reserves through the relevant Activities Declaration^[11]A statutory document under the Nature Conservation Act 2014 which sets out the permitted activities within a reserve.. While there are individual and potentially social benefits to allowing dogs in reserves, it can only have a detrimental effect on nature conservation. Trade-offs among the outcomes need to be described and the risks of trying to balance competing objectives discussed explicitly. In addition, monitoring should be put in place to enable an assessment of policy effectiveness and adjust the management approach if required.

Condition and monitoring

As discussed above, it is not currently possible to determine the condition of conservation areas in the ACT. The introduction of the CEMP in 2018 should address this gap by providing information on ecosystem condition and change over time, but it is still too early for comprehensive data to be available. The condition assessments will integrate the influence of a range of environmental drivers, pressures and the combined effects of management actions. Given the challenges of identifying trends, it is likely that the CEMP may take some time to detect anything except major changes arising from notable climate and weather events.

As discussed elsewhere in this report, adaptive management is critical when considering restoration of degraded systems subject to multiple threats. Condition monitoring is only one step in adaptive management. It is important also to plan evaluation to ensure that there is information on the management activities undertaken, their outputs and contribution to objectives.

This is illustrated by the fact that management activities are currently being undertaken that could be expected to directly improve environmental conditions include revegetation, fish stocking, fish habitat installation, and pest and weed management. Clearly there has been some strategic planning in the detailed design of these activities but they are also activities that have been core business for government agencies for decades. Without clear evaluation of the outcomes from these activities based on reliable data, it is possible that resources are being expended on management interventions which are not producing the desired outcomes. The ongoing declines in condition of ecosystems and threatened species raises the question of whether business as usual is adequate.

The gaps in condition and intervention monitoring are serious deficiencies within the management program that compromise its integrity. It is not possible to design effective interventions without robust information on the condition of the system and the success (or otherwise) of management actions.

Appendix 1: Threatened species in the ACT