Greater Blue Mountains Area

The extreme fires in the GBMA and across south-eastern Australia over several months in 2019/20 reflect climate changes that have affected fire regimes that have led to increasing dry fuel loads. The NSW government released an immediate response plan in January for recovery actions and wildlife protection (Department of Planning Industry and Environment, 2020). A wider conservation response to the fires across Australia was prepared by Dickman et al. (2020) to outline priority actions and a blueprint for responding to such large-scale ecological disaster. The GBMA has one of the world’s most fire-prone ecosystems. Initial estimates in early 2020 showed that potentially up to 82% (853,977 hectares) of the site was affected by fires that burned at greatly varying intensities for more than 3 months from end October 2019 to early February 2020 (State Party of Australia, 2020). A more detailed analysis using the Fire Extent and Severity Mapping (FESM) method, has shown that it is about 71% (IUCN Consultation, 2020c). Some areas burnt with lower intensity and provided critical refugia for some species. Impacts on species will not be fully understood until further monitoring is done. The fires were followed in February by torrential rain which also significantly impacted the property, with flash flooding resulting in increased sediment, debris and ash runoff and erosion of some watercourses and unsealed access routes across the site.
Of the 587 fires that have occurred within the Greater Blue Mountains Area over the last 15 years, 67% (393) were contained to less than 10 ha and only 25 fires (<5%) were larger than 1,000 ha. During the 2019-20 fire season there were 41 ignitions (primarily as a result of lightning) across the World Heritage site. 20 of those remote ignitions were successfully contained by NPWS Remote Aerial Response Teams (RART) to an average fire size of less than 1.2 ha. This action contributed significantly to reducing the impact of the larger fires (IUCN Consultation, 2020c).
Many species that are attributes of the Outstanding Universal Value of the site were impacted by the fires (State Party of Australia, 2020). An evaluation of species impacts will draw together information on the status of species prior to the fires, the degree to which their range is within the fire extent and past fire impacts and traits which provide insights into the vulnerability of each species to fire. These traits will also help to identify actions which are required to support the recovery of each priority species. Actions have commenced to reduce the impacts from introduced carnivores and herbivores and weeds on fire-affected native plants and animals. The NSW Government is developing and implementing targeted ongoing monitoring programs to assess impacts and monitor recovery of species. Main ongoing threats relate to the impact of altered or inappropriate fire regimes on the ecological, biological and evolutionary processes within the eucalypt-dominated ecosystems (e.g. Barker and Price 2018), and the impact of inappropriate fire regimes on the quality of habitats for in-situ conservation of the biological diversity of primitive species with Gondwanan affinities and of rare or threatened plants and animals.
The Final Report of the NSW Bushfire Inquiry has been released (https://www.nsw.gov.au/nsw-government/projects-and-initiatives/nsw-bushfire-inquiry) with all 76 recommendations supported by the NSW Government Outcomes from the state inquiry, will help  inform the NSW Government response in terms of future fire management approaches. The Royal Commission into National Natural Disaster Arrangements report was released to the Australian Governor-General on 28 October 2020 (https://naturaldisaster.royalcommission.gov.au/).

The Wollangambe, Wolgan and Colo Rivers are affected by polluted water from collieries. The Colo (and its major tributaries that include the Wolgan and Wollangambe, see DECCW, 2008) is a dedicated Wild River (Benson et al., 2012; Hansen, 2010). In July 2015, coal fines from the Clarence Colliery collapsed into the Wollangambe River, resulting in pollution within the World Heritage site. The mining company was prosecuted and required to pay an environmental compensation, in addition to covering clean-up works. The State Party investigated the incident and remediation works, and concluded that there have been no long-term impacts on the OUV of the site (State Party Report, 2019; UNESCO, 2019). More recent research (Wright et al., 2017) reports that pollution from the mine extends at least 22 km downstream in the Wollangambe from the outflow of coal mine wastes. The resulting water pollution is causing major impairment of the aquatic ecosystem, with reduced abundance, taxonomic richness and loss of pollution-sensitive macroinvertebrate groups. Water pollution from the mine includes thermal pollution, increased salinity, and increased concentrations of a wide range of heavy metals that appear to have been mobilised into riparian vegetation (Wright et al. 2017; Belmer and Wright, 2018). Further assessment of the implications of heavy metal mobilisation to the terrestrial environment from waterways is recommended because if heavy metal contaminants are leaving the water column of their receiving waterways and mobilising to the terrestrial environment, serious long-term legacy pollutant impacts may persist (Belmer and Wright, 2018). There has also been serious ongoing heavy metal pollution (zinc and nickel) from Canyon Colliery that flows into the Grose river in the WHA (see Wright, 2020).

Subsidence from long wall coal mining close to the boundary of the GBMA threatens cliff collapse, water pollution, lowering of water tables, desiccation of peat swamps and the loss of surface water (Independent Expert Panel for Mining in the Catchment, 2019). The Temperate Highland Peat Swamps on Sandstone (THPSS) are a Threatened Ecological Community (TEC) (New South Wales Scientific Committee 2007; New South Wales Government Office of the Environment and Heritage, 2014; Commonwealth of Australia, 2014) and their water retention and ecological function (including providing base flow to downstream catchments) is shown to be impacted by mining, along with impacts of climate change and extreme fire (Cowley et al. 2019). In the THPSS swamps studies by Cowley et al. (2019) 70% of the water in the 4 of 5 swamps came from the surrounding bedrock aquifer, indicating the major impact subsidence can cause by removing water. The high floristic diversity of the swamps has been previously underestimated (Tierney et al. 2018). The threats are greatest in the Gardens of Stone area on the Newnes Plateau (containing many upland swamps that are listed as threatened under the EPBC Act, with fauna including two threatened species, the Blue Mountains Water Skink and the Giant Dragonfly; flows in the Wolgan River that runs through the GBMA may also be affected) (Department of Sustainability, Environment, Water, Population and Communities, 2013; Goldrey et al., 2010). The 2020 Centennial Angus Place Extension Report (ERM 2020) notes that "development of fractures within the sandstone bedrock underling watercourses across the Study Area caused by mining subsidence could significantly increase local hydraulic conductivity. This can significantly reduce, or in some cases effectively eliminate baseflow. This loss of flow can lead to the progressive drying of downstream swamps which can result in a range of impacts including loss of wetland plant species, drying and desiccation of the swamp peat, increased potential for incision, and erosion of the swamp surface during high flow events".

Control measures for invasive species are outlined in national park management plans, which are implemented in cooperation with neighbours. Invasive fauna include foxes, cats, carp, deer, dogs, goats, horses, pigs, rabbits, and cattle. The greatest threat is from introduced predators (foxes and cats) (Pascoe, 2011; Pascoe et al., 2011). Fire-affected landscapes leave native animals more exposed to predation by feral cats, dogs and foxes. Native animals are competing for scarce food with feral deer, pigs and goats. After the 2019/20 fires, feral animal control is underway to protect native animals while their habitat recovers. Invasive plants are well adapted to colonise burnt areas and may become more prevalent and out-compete native species. Targeted post-fire weed control to support the recovery of native flora is being planned and implemented (IUCN Consultation, 2020c).

Visitation is managed to minimise impact while supporting the visitor experience and appreciation of values. Tourism development due to increasing visitor pressure and infrastructure is discussed in the GBMA strategic plan. The development of the Emirates Resort inside the Wollemi National Park was negotiated as a land swap of previously disturbed farmland within the park for high conservation freehold land. The process has been stalled because the land swap is subject to negotiating an Indigenous Land Use Agreement and this has not been finalised. The section of the Resort on park is subject to a 21-year lease to allow the land swap to be resolved.

Temperate highland peat swamps on sandstone (THPSS) are unique state and federally protected ecological communities comprising multiple swamp communities (Blue Mountains Swamps and Newnes Plateau Shrub Swamps) (New South Wales Scientific Committee, 2007; Hensen, 2010; New South Wales Government Office of the Environment and Heritage, 2014; Commonwealth of Australia, 2014). These habitats provide the function of carbon sinks, refuge for unique, often endemically isolated biodiversity and act as safeguards for water quality and unremitting flow regimes (Keith et al., 2014). Urban runoff within THPSS catchments is affecting the condition of their aquatic ecosystems (Belmer et al., 2018). However, at the scale of the World Heritage site, this threat is rather localized.

Habitat die-off and uncontrollable wildfire is predicted to continue, in response to climate change and associated drought and extreme weather (Blue Mountains World Heritage Institute, 2006; IUCN Consultation, 2017). Torrential flooding exacerbated the impacts of the recent fires had a significant impact on infrastructure of the GBMA. There is concern that climate change could result in increased incidences of flora and fauna disease outbreaks including zoonoses (Bender et al., 2018). Climate change is already impacting on Threatened Highland Peat Swamps on Sandstone (THPSS) placing them under greater stress (Hensen, 2010). Climate change and associated drought and fire may impact on rainforest and wet schlerophyll communities also (Hamill and Tasker, 2010). Canopy dieback has been observed in the Greater Blue Mountains Area in 2019 (IUCN Consultation, 2020b).

Degradation of habitat compromises the health of wildlife, and the recent bushfires and extreme weather patterns increase the risk of diseases in wildlife populations that have their habitats and natural movement patterns disrupted (Bender et al., 2018). A number of diseases have been recorded in several species in the World Heritage site. Chlamydia has been confirmed in Eastern Rosella and King Parrots from multiple submissions from the Blue Mountains area (Australian Registry of Wildlife Health). Other diseases present include chytridiomycosis in frogs (Scheele et al., 2019; NSW Threatened Species Scientific Committee). Increased incidence of plant pathogens, Phytophthora cinnamomi and myrtle rust (Austropuccinia psidii) are also likely. The root rot pathogen Phythophthora cinnamomi causes vegetation dieback and may become more widespread due to climate change and habitat that is less resilient. It is spread by human activities (including on boots, bikes and vehicles) and moves from ridge tops down slopes and water courses (Blue Mountains World Heritage Institute, 2012; National Parks and Wildlife Service, 2012; Newby, 2014). A general survey of Wollemi National Park for Phytopthora cinnamomi found the pathogen was present in samples collected over extensive areas (McDougall and Summerell, 2003; Daniel et al., 2006; DEC, 2006). The disease in its east coast manifestation has a selective impact removing susceptible species so altering the makeup of the ecosystem.