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- Impact assessment for the Beetaloo GBA region (stage 3)
- 4 Assessment results
- 4.4 Potential impacts on protected fauna
Six protected matters were prioritised for more detailed assessment based on the importance of the Beetaloo GBA extended region to the continued persistence of each species (Huddlestone-Holmes et al., 2020). ‘Persistence’ is the survival and maintenance or extension of occupied area of a species in its current habitat, in the Beetaloo GBA extended region over a time frame much longer than the unconventional gas resource development life cycle. Those assessed were:
- 4 bird species: the Australian painted snipe (Rostratula australis), crested shrike-tit (northern) (Falcunculus (frontatus) whitei), Gouldian finch (Erythrura gouldiae), grey falcon (Falco hypoleucos)
- 1 marsupial: greater bilby (Macrotis lagotis)
- 1 aquatic reptile: Gulf snapping turtle (Elseya lavarackorum).
The Beetaloo GBA region changes from tropical in the north to semi-arid in the south. Tropical savanna species are found in the north (for example, the Gouldian finch) and typical Australian desert species are found in the south (for example, the greater bilby). As the region becomes more widely surveyed, more species are expected to be added to biodiversity records. As water controls the ecology and movements of the 6 protected fauna quite differently, these species were selected to better understand the potential impacts of unconventional gas resource development. Any decline in persistence is assumed to be material.
Pathways between activities and fauna endpoints of ‘potential concern’ are primarily related to activities that create a disturbance at the surface ( civil construction decommissioning and rehabilitation transport of materials and equipment and seismic acquisition ). The pathways of ‘potential concern’ connect these activities with key stressors, namely invasive plants and insects and vegetation removal that result in mortality of native species and habitat degradation, fragmentation and loss . Common processes within these pathways that are of ‘potential concern’ are competition and predation , and ecosystem burning . The aquatic Gulf snapping turtle may be affected by surface water contamination processes while the Gouldian finch, crested shrike-tit (northern), greater bilby and grey falcon may be affected by increases in invasive carnivores as a result of artificial water sources
Gulf snapping turtle
The Gulf snapping turtle lives near permanent water bodies, occupying deep water pools along permanently flowing spring-fed rivers. However, it is also dependent on riparian vegetation that fringes its aquatic habitat to provide stable banks, where the species breeds by laying eggs in the soil, and to provide habitat for the plants that provide its food. It has been noted that densities of Gulf snapping turtle are lower adjacent to riparian vegetation that is degraded by invasive plants and/or fire. As the food plants of the turtle occupy fire-sensitive riparian vegetation, fire is seen as a process that opens the canopy and facilitates weed invasion during seasonal flooding. Therefore, the Gulf snapping turtle is vulnerable to disturbances that impact both freshwater condition and availability, and the condition and availability of riparian vegetation.
Potential impacts for the Gulf snapping turtle due to unconventional gas resource development relate to civil construction , decommissioning and rehabilitation , and transport of materials and equipment ( Figure 13 ) activities. The aquatic habitat of the species is potentially affected by surface water contamination generated by the stressors of accidental release (directly or via a pathway through soil contamination), overland flow obstruction , soil compaction and vehicle movement (via a pathway through soil erosion and sedimentation). Riparian vegetation on which the species depends is potentially affected by habitat degradation, fragmentation and loss generated by the stressors of invasive plants and insects (directly or via a pathway through ecosystem burning), vegetation removal and vehicle movement (via a pathway through ecosystem burning).
Australian painted snipe
The semi-aquatic Australian painted snipe is also considered to be water dependent but does not live in water. It shelters among vegetation adjacent to wetlands and forages during twilight hours in shallow, brackish or freshwater wetlands including lakes, swamps, claypans, inundated or waterlogged grassland and saltmarsh and artificial wetlands. It forages by probing the soft mud with its bill, consuming seeds and invertebrates.
Potential habitat for the Australian painted snipe in the Beetaloo GBA region consists of small and shallow ephemeral wetlands. These appear infrequently in the region in response to rainfall. The species is nomadic and does not occupy an area if suitable wetlands are not available. It leaves once wetlands dry.
Potential impacts for the Australian painted snipe due to unconventional gas resource development relate to civil construction , decommissioning and rehabilitation , transport of materials and equipment , waste and wastewater management , and seismic acquisition ( Figure 13 ) activities. The majority of pathways involve invasive plants and insects as the key stressor. vegetation removal is also an important stressor for the species. The pathways from invasive plants and insects and vegetation removal conclude either in mortality of native species or habitat degradation, fragmentation and loss . Competition and predation and ecosystem burning feature as processes in some of these pathways. Pathways involving stressors related to water availability and condition such as surface water availability and surface water contamination are not considered to be of ‘potential concern’ for the Australian painted snipe.
FIGURE 13 Level of concern for causal pathways from activities to endpoints for the Beetaloo GBA region
Endpoints are on the x axis and activities on the y axis. The colours of the squares show the level of concern for the pathway, and the size of the squares shows the percentage of the endpoint area potentially impacted. Where a square has multiple colours, it indicates that there are different levels of concern spatially for the endpoint. Activities are ordered from surface to subsurface and endpoints are ordered from subsurface to surface.
Source: Geological and Bioregional Assessment Program (2021g)
Element: GBA-BEE-3-547
Gouldian finch
The Gouldian finch, although a terrestrial species, is reliant on daily access to water to drink. This reliance on water influences its movement, ecology and activities throughout the year. In addition, the Gouldian finch has distinct nesting and foraging habitat. It breeds in the hollows of eucalypt species on rocky hills and feeds on grass seed. As a result it has a complex life cycle that involves the use of discrete environments across the annual cycle. The Gouldian finch is vulnerable to disturbances that impact the availability and condition of specific aspects of the terrestrial vegetation in which it nests and feeds.
Potential impacts for the Gouldian finch due to unconventional gas resource development relate to civil construction , decommissioning and rehabilitation , transport of materials and equipment , and waste and wastewater management activities ( Figure 13 ). The majority of pathways involve invasive plants and insects as the key stressor. vegetation removal is also an important stressor for the Gouldian finch. The pathways from invasive plants and insects and vegetation removal conclude either in mortality of native species or habitat degradation, fragmentation and loss . Important processes in these pathways are competition and predation , and ecosystem burning . vehicle movement can also result in ecosystem burning. Overall, confidence that these pathways are of ‘potential concern’ or ‘low concern’ is medium based on available literature and local assessment of potential invasive plant species, although the knowledge base for thresholds of material change is limited.
Artificial water sources from civil construction and waste and wastewater can increase competition and predation through facilitating spread of invasive carnivores resulting in mortality of native species . This pathway is of ‘low concern’ but confidence is low owing to a lack of local studies or data and an inadequate knowledge base to define and evaluate a material change.
Crested shrike-tit (northern)
The water requirements of the crested shrike-tit (northern) are unknown. It may require daily access to water like the Gouldian finch or it may be able to obtain all (most) of its water requirements from its prey. The species is arthropodivorous, that is it feeds on invertebrates, mostly insects and spiders, in the foliage, branches, trunk and bark of trees. The potential geographic range of the crested shrike-tit (northern) overlaps with that of the Gouldian finch. Both species are characteristic of savanna woodlands in the north of the Beetaloo GBA region. The crested shrike-tit (northern) occurs in woodland and open woodland dominated by a range of Eucalyptus and Corymbia species. It also breeds in this habitat, constructing a cup-shaped nest from fibre, bark and other materials, near the top of a eucalypt, bloodwood or paperbark tree.
The crested shrike-tit (northern) is very similar to the Gouldian finch in terms of the potential impacts posed by unconventional gas resource development. Potential impacts due to unconventional gas resource development relate to civil construction , decommissioning and rehabilitation , transport of materials and equipment , and waste and wastewater management activities ( Figure 13 ). The majority of pathways involve invasive plants and insects as the key stressor. vegetation removal iis also an important stressor for crested shrike-tit (northern). The pathways from invasive plants and insects and vegetation removal conclude either in mortality of native species or habitat degradation, fragmentation and loss .
Important processes in these pathways are competition and predation , and ecosystem burning . vehicle movement can also result in ecosystem burning. Artificial water sources from civil construction and waste and wastewater management can increase competition and predation through facilitating spread of invasive carnivores, resulting in mortality. This pathway can also happen directly without artificial water sources being involved.
Overall, confidence that these pathways are of ‘potential concern’ or ‘low concern’ is low to medium based on available literature and limited local evidence. The knowledge base for thresholds of material change is also limited.
Greater bilby
The greater bilby is a ground-dwelling marsupial occurring across the western deserts of the Northern Territory and Western Australia. The south-west of the Beetaloo GBA region is at the extreme north-east edge of its range. Bilbies are nocturnal, sheltering during the day in burrows. The species has an omnivorous diet. Invertebrates, especially termites, are relied upon when plant food is scarce. The greater bilby does not require daily access to water.
Although the greater bilby differs from the Gouldian finch in not having a requirement for regular access to water, the pathways of ‘potential concern’ for the bilby are the same as for the Gouldian finch. These pathways relate to civil construction , decommissioning and rehabilitation , transport of materials and equipment , and waste and wastewater management activities ( Figure 13 ). Most pathways involve invasive plants and insects as the key stressor. vegetation removal is also an important stressor. The pathways from invasive plants and insects and vegetation removal conclude either in mortality of native species or habitat degradation, fragmentation, and loss . Important processes in these pathways are competition and predation , and ecosystem burning . vehicle movement is a stressor that can result in ecosystem burning. Artificial water sources from civil construction and waste and wastewater management can increase competition and predation by facilitating spread of invasive carnivores, resulting in mortality. This pathway can occur directly without artificial water sources being involved. The greater bilby is at more risk than the other fauna species from pathways involving predation by introduced carnivores because it is in the weight range of mammals with a heightened probability of extinction from predation by cats and foxes.
Overall, confidence that these pathways are of ‘potential concern’ or ‘low concern’ is medium based on available literature and local evidence, although the knowledge base for thresholds of material change is limited.
Grey falcon
The grey falcon is a predatory bird endemic to Australia. It is well known for being the only species among the world’s 39 species of falcons that is confined to arid and semi-arid regions (although occasional vagrants move outside this area). The grey falcon is unique among the 6 species of protected fauna prioritised for the Beetaloo GBA region in that it uses space at a large scale. The grey falcon is generally nomadic although individuals can occupy specific areas for prolonged periods of time. Non-breeding birds undertake wide-ranging trips of up to several hundred kilometres whereas breeding birds typically remain within a radius of around 20 km of the nest. Grey falcons also make use of human structures (telecommunication towers, repeater stations) as nesting sites and can capture their preferred prey (birds, especially pigeons, doves, parrots and finches) around artificial water sources.
The pathways of ‘potential concern’ for grey falcon are similar to those of the greater bilby. Most pathways involve invasive plants and insects as the key stressor. vegetation removal is also an important stressor. The pathways from invasive plants and insects and vegetation removal conclude either in mortality of native species or habitat degradation, fragmentation, and loss . Important processes in these pathways are competition and predation , and ecosystem burning . vehicle movement is a stressor that can result in ecosystem burning. Artificial water sources from civil construction and waste and wastewater management can increase competition and predation by facilitating spread of invasive carnivores resulting in mortality. This pathway can also be direct without artificial water sources being involved – for example, predation by cats and foxes is an emerging threat for grey falcons.
Overall, confidence that these pathways are of ‘potential concern’ or ‘low concern’ is medium based on available literature and local evidence, although the knowledge base for thresholds of material change is limited.