Roger Lembit, Ecologist
The National Parks of the Blue Mountains, which form the Greater Blue Mountains World Heritage Area, have been the site of extensive and unprecedented bushfires, which have raised concern internationally about the status of these parks.
This article seeks to identify some of the effects of the fire on World Heritage and other significant values, the extent to which the integrity of the GBMWHA has been impacted and possible measures which can be taken to mitigate impacts and to ensure future management builds from the lessons of these fires and addresses coming challenges.
Background
The Greater Blue Mountains World Heritage Area (GBMWHA) covers over 1,000,000 hectares across several National Parks including Wollemi, Gardens of Stone, Blue Mountains, Kanangra-Boyd and Nattai.
The GBMWHA is dominated by temperate eucalypt forest, but also includes rainforest, woodland, heath and swamps. The area supports exceptional biodiversity including a high number of rare and endemic plants. It is also highly valued for its Aboriginal heritage and its outstanding geological features, such as sandstone cliffs, slot canyons and waterfalls.
The GBMWHA was inscribed on the World Heritage List in November 2000. The area was listed as it supports outstanding biodiversity values (see Appendix), with around 100 eucalypt species occurring in sclerophyll ecosystems in an extraordinarily diverse area rich in natural and cultural values.
The GBMWHA incorporates the largest integrated system of protected areas in New South Wales and provides outstanding opportunities for the conservation of natural communities and processes. It includes the most extensive aggregations of temperate eucalypt wilderness in south-eastern mainland Australia.
Impacts on World Heritage Values
The 2019-20 bushfires have burnt through around 80% of the GBMWHA as at 6th January 2020. While on-ground post-fire assessments are yet to occur, it is inevitable that there has been considerable impact on the biological and geological elements that contribute to these values.
Many of the eucalypt species are resprouters and would normally regrow after a fire. Populations of the obligate seeder, Blue Mountains Ash (Eucalyptus oreades), have been affected. This includes populations of this species that were previously affected by the October 2013 State Mine Fire. The status of resprouter species is also of concern. Intense fires have been observed to result in the death of up to 20% of mature, rough-barked eucalypts. Some of the eucalypts recorded from the GBMWHA are of restricted distribution and these fires may have imperilled the long term viability of these populations.
Montane bogs and fens of the Boyd and Newnes Plateaux have burnt. These swamps have developed since the last Ice Age and may have existed in their present form for less than 15,000 years. Some areas within these swamps are likely to have suffered from intense heat and consumption of peat layers built up over thousands of years. An unusual raised bog on the Boyd Plateau is also within the burnt area.
The GBMWHA also supports stands of rainforest vegetation and refugia (small areas) for rainforest species. These include elements of warm temperate, cool temperate and dry rainforest. Some areas supporting cool temperate rainforest trees and shrubs had not been burnt for 90 years or more. These include patches of Possumwood (Quintinia sieberi) in sheltered areas below cliff faces in the Kanangra Walls area. River-flats along the Kowmung River and tributaries also supported rainforest species including regenerating Red Cedar (Toona ciliata) trees. It is likely some of these trees have been affected, although, for some, their existence in sheltered habitats may have protected them. Some may have the capacity to resprout.
Another area of warm temperate rainforest dominated by Sassafras (Doryphora sassafras) occurs on Mount Coriaday in Wollemi National Park. The Kerry Ridge bushfire passed through this area. The Mount Coriaday rainforest supports primitive species such as Native Mulberry (Hedycarya angustifolia). Floyd (1990) felt that this rainforest was being replaced at its southern edge by Blackwood (Acacia melanoxylon) and stated that “The rainforest is at a critical stage in its history and could easily be eliminated by any increase in burning”.
Of the primitive and relictual plant groups plants listed in the Appendix, representatives of the genus Lomatia are likely to have been burnt. Long unburnt Boyd Plateau populations of Lomatia myricoides are likely to have been affected. Another primitive species which occurs on the Boyd Plateau is the Mountain Pepper (Tasmannia lanceolata). Its fire response, at the northern part of its range, is poorly known.
A number of threatened plant species would have populations affected by the fire. The exact extent and intensity of the fires is not clear, but it seems that all populations of the Kowmung Hakea (Hakea dohertyi) are within burnt zones. This Hakea is an obligate seeder and appears to have closer affinities to Hakeas which occur further south into Victoria and Tasmania. The rare Kanangra Wattle (Acacia clunies-rossiae) occurs entirely within Blue Mountains and Kanangra-Boyd National Parks. While many plants survived the 1997 bushfires which burnt through a significant section of this Acacia’s habitat, it is unclear what effect these recent fires may have had, given the prolonged period of dry weather preceding the fire.
A number of threatened fauna species may have been severely affected by the fires. The Kowmung River and Gospers Mountain fires have burnt across important habitat for the Greater Glider, a species which is listed as threatened under the Commonwealth Environment Protection and Biodiversity Conservation Act. Frogs that inhabit the Boyd Plateau Montane Bogs and Fens would also have suffered. Sections of the Boyd Plateau and the northern part of the Newnes Plateau support Koala habitat. If the fires have crowned in these areas, these Koala populations may no longer be viable.
Impacts on Integrity
Listing of a place as World Heritage requires the State Party (the Australian Government) to address issues of integrity of the site; the extent to which threats can be managed and degraded areas restored.
Feral predators, such as cats and foxes, are one such threat which can place significant pressure on native animals which survive a fire, particularly when water is scarce, as it is now across the GBMWHA.
The decline of plants with small populations is another issue which impacts on the integrity of World Heritage values.
Review the Plans
The Strategic Plan for the GBMWHA was completed in 2009. The year 2020 will be the 20th Anniversary of the inscription of the site on the World Heritage list. A new Strategic Plan is under review. Further review is desirable, learning from the experience of these bushfires and other issues which have arisen since the current strategic plan was published.
The individual park plans, including Wollemi, Blue Mountains and Kanangra-Boyd have been identified for review some years ago. It is timely for funding to be provided for a comprehensive review and public appraisal of planning for these key parks within the GBMWHA.
Understand the Impact
Bushfires usually don’t burn across the landscape at the same intensity, there will be patches where the fire remains at ground level, whilst in other areas the canopy will be completely consumed. Remote sensing can be used after a fire to characterise the pattern of fire intensity across the landscape. This fire intensity mapping needs to be matched to records of distribution of threatened flora and fauna to determine priorities for pest species management and other threatened species recovery actions.
Understanding the nature of plant species recovery can inform management needs and future priorities in conservation action and planning for bushfire hazard reduction.
It is important that both the NSW Government and Commonwealth Government act to properly fund recovery actions across the GBMWHA, including immediate funding for targeted pest species management and for research relating to fire intensity and species recovery.
References
DECC (2009) Greater Blue Mountains World Heritage Area. Strategic Plan January 2009. DECC, Sydney.
DEE (2019) Webpage http://www.environment.gov.au/heritage/places/world/blue-mountains Australian Government. Department of the Environment and Energy, Canberra.
Floyd (1990) Australian Rainforests in New South Wales Volume 2. Surrey Beatty & Sons, Chipping Norton.
APPENDIX World Heritage Values of the Greater Blue Mountains World Heritage Area
In terms of the World Heritage Convention the GBMWHA has values considered significant according to the following criteria (DEE 2019):
Criterion (ix): be outstanding examples representing significant on-going ecological and biological processes in the evolution and development of terrestrial, fresh water, coastal and marine ecosystems and communities of plants and animals:
The Greater Blue Mountains include outstanding and representative examples in a relatively small area of the evolution and adaptation of the genus Eucalyptus and eucalypt-dominated vegetation on the Australian continent. The site contains a wide and balanced representation of eucalypt habitats including wet and dry sclerophyll forests and mallee heathlands, as well as localised swamps, wetlands and grassland. It is a centre of diversification for the Australian scleromorphic flora, including significant aspects of eucalypt evolution and radiation. Representative examples of the dynamic processes in its eucalypt-dominated ecosystems cover the full range of interactions between eucalypts, understorey, fauna, environment and fire. The site includes primitive species of outstanding significance to the evolution of the earth’s plant life, such as the highly restricted Wollemi pine (Wollemia nobilis) and the Blue Mountains pine (Pherosphaera fitzgeraldii). These are examples of ancient, relict species with Gondwanan affinities that have survived past climatic changes and demonstrate the highly unusual juxtaposition of Gondwanan taxa with the diverse scleromorphic flora.
Criterion (x): contain the most important and significant natural habitats for in-situ conservation of biological diversity, including those containing threatened species of Outstanding Universal Value from the point of view of science or conservation:
The site includes an outstanding diversity of habitats and plant communities that support its globally significant species and ecosystem diversity (152 plant families, 484 genera and c. 1,500 species). A significant proportion of the Australian continent’s biodiversity, especially its scleromorphic flora, occur in the area. Plant families represented by exceptionally high levels of species diversity here include Myrtaceae (150 species), Fabaceae (149 species), and Proteaeceae (77 species). Eucalypts (Eucalyptus, Angophora and Corymbia, all in the family Myrtaceae) which dominate the Australian continent are well represented by more than 90 species (13% of the global total). The genus Acacia (in the family Fabaceae) is represented by 64 species. The site includes primitive and relictual species with Gondwanan affinities (Wollemia, Pherosphaera, Lomatia, Dracophyllum, Acrophyllum, Podocarpus and Atkinsonia) and supports many plants of conservation significance including 114 endemic species and 177 threatened species.
The diverse plant communities and habitats support more than 400 vertebrate taxa (of which 40 are threatened), comprising some 52 mammal, 63 reptiles, over 30 frog and about one third (265 species) of Australia’s bird species. Charismatic vertebrates such as the platypus and echidna occur in the area. Although invertebrates are still poorly known, the area supports an estimated 120 butterfly and 4,000 moth species, and a rich cave invertebrate fauna (67 taxa).
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