The Avifauna of Bungalbin, Western Australia – an Arid Region with Minimal Human Impact
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Australian Field Ornithology 2020, 37, 1–14 http://dx.doi.org/10.20938/afo37001014 The avifauna of Bungalbin, Western Australia – an arid region with minimal human impact Michael D. Craig1, 2* and Glenn I. Moore1, 3 1School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Nedlands WA 6009, Australia 2Department of Veterinary and Life Sciences, Murdoch University, Murdoch WA 6150, Australia 3Department of Aquatic Zoology, Western Australian Museum, 49 Kew Street, Welshpool WA 6106, Australia *Corresponding author. Email: [email protected] Abstract. The Bungalbin area in the Great Western Woodlands of Western Australia has remained relatively free of anthropogenic impacts and we report on the occurrence and abundance of 94 bird species recorded in the area up to 1993. This rich avifauna reflects not only the low anthropogenic impacts in the area but also its position between the Bassian and Eremaean biogeographic zones and the diversity of vegetation types present. The most important habitats for birds were Salmon Gum Eucalyptus salmonophloia woodlands, areas of Tammin Mallee E. leptopoda, and Acacia aff. aneura shrublands. The area is likely to be regionally significant for the threatened Malleefowl Leipoa ocellata as well as containing good populations of several uncommon species. However, the area is under threat from mining and this list will provide an important baseline to compare with contemporary surveys, to inform future management of what is a relatively pristine part of the arid zone of Australia. Introduction Western Australia (also known as the Goldfields), is one of the areas least affected by anthropogenic impacts in the In the more than 200 years since European settlement, southern arid zone, and has no history of livestock grazing. anthropogenic impacts, such as introduced herbivores This area lies north of the Western Australian Wheatbelt, (European Rabbits Oryctolagus cuniculus and livestock), where extensive clearing of land for growing grain and introduced predators (Cats Felis catus and Red Foxes grazing sheep has dramatically altered the avifauna Vulpes vulpes) and altered burning regimes, have (Saunders & Ingram 1995), and south of the pastoral zone, changed the ecology of arid Australia irreversibly. While where the introduction of livestock and artificial watering many mammal species have been lost (McKenzie et al. points has significantly altered the vegetation and avifauna 2007; Pedler et al. 2016), the avifauna of the arid zone (Davies et al. 2010; Eldridge et al. 2016). Furthermore, has been less severely affected. Although many species before the 21st century, the area had almost no history of have declined in range and abundance (Saunders & Curry human exploitation, and the lack of artificial watering points 1990; Smith et al. 1994), and some subspecies have been and permanent fresh water has meant that the number of lost (Garnett et al. 2011), so far no species of bird has feral animals was extremely low (Dell et al. 1985). This been lost (Morton 1990; Recher & Lim 1990). The basis lack of permanent fresh water also means that the number for this dichotomy is unclear, but Morton (1990) postulated of kangaroos is unlikely to have changed significantly that birds have survived better than mammals for two since European colonisation. The area has also escaped primary reasons. Firstly, no bird is entirely herbivorous in large-scale wildfires that have become prevalent in many the sense that it eats only green vegetation, thus reducing parts of Australia’s arid zone (Gosper et al. 2018, 2019a,b) direct competition with rabbits and introduced livestock. and contains a rich mosaic of habitats characteristic of the Secondly, birds have much greater dispersal capabilities southern arid zone of Australia (Dell et al. 1985; Fitzsimons than mammals and hence are more likely to recolonise et al. 2014; Fox et al. 2016). An understanding of the an area after drought or other disturbances, reducing the avifauna of this area could help us to better understand probability of local extinctions. However, the avifauna of how to conserve birds in the arid zone (see also Fox et al. the arid zone remains vulnerable and it is predicted that 2016). continuing degradation of arid-zone ecosystems will lead The vertebrate fauna of the area was surveyed by to an accelerated loss of avian species parallel to earlier the Western Australian Museum (WAM) as part of the losses of mammal species (Recher & Lim 1990). The Biological Survey of the Eastern Goldfields, as the region main threats are continued overgrazing by livestock, feral was then known (Dell et al. 1985). During three trips from animals, increased numbers of kangaroos (Macropodidae), September 1979 to December 1981, 67 species of birds inappropriate burning regimes (often resulting from weed were recorded and their abundance estimated in eight invasion) and climate change (Smith et al. 1994; Miller vegetation types. During the course of fieldwork with et al. 2010; Smith 2015; Mutze 2016; Connell et al. 2017). researchers from the University of Western Australia, we One of the difficulties in understanding the decline visited the region repeatedly from May 1988 to November of birds in the arid zone, and managing landscapes to 1993 and recorded all birds sighted in a manner similar to prevent these declines, is the paucity of information about Dell et al. (1985). The purpose of this work was to provide the avifauna at sites relatively unaffected by anthropogenic baseline data for a relatively unaltered area of the arid impacts. The Bungalbin area, north of Southern Cross zone. These data could be used both to compare long- in the northern part of the Great Western Woodlands of term changes in the avifauna of the Bungalbin area and 2 Australian Field Ornithology M.D. Craig & G.I. Moore to compare with areas more heavily impacted by humans. This would then facilitate the identification of the species of greatest conservation concern and potential reasons for their decline. The questions we asked were: (1) What is the abundance of species in the area? (2) Have any significant changes in the avifauna occurred since 1981? and (3) Which habitats appear to be most utilised by birds? Methods Study area The area of observations included in this study covers part of the area called Bungalbin by the Kapurn people, the traditional owners of the country, and extends from the central Helena and Aurora Ranges ~3.5 km north- north-east of Bungalbin Hill (30°21′S, 119°40′E) in a north- easterly direction to a granite outcrop called Kurrajong Rock (30°11′S, 119°53′E) ~45 km north-east of Bungalbin Figure 1. Aerial photograph of the study area showing its Hill (Figure 1). The observations cover an area several location in Western Australia (inset) and outlined in pale kilometres either side of a line drawn between these two grey in the main photograph (taken in January 2004). points and the northern half of the Helena and Aurora In the south of the study area lie the Helena and Aurora Ranges. Bungalbin Hill itself, at the south-western end of Ranges, which are covered primarily with Sandplain the Helena and Aurora Ranges, is ~97 km north-north-east Mallee Eucalyptus ebbanoensis Mallee (JK18) interspersed of Southern Cross in the Great Western Woodlands. with tiny patches of Yilgarn Banksia Banksia arborea Tall Shrubland (JK21). Surrounding the Helena and Aurora Although no long-term weather monitoring occurs Ranges, in a reddish colour, is Salmon Gum E. salmonophloia at the site, data from the two closest weather stations, Woodland (JK44) and to the north-east of that, showing as a mix of pale and green, is Tammin Mallee E. leptopoda Windarling (45 km north-west; open 2004–2017) and Mallee (JK35) interspersed with small patches of Swordfish Koolyanobbing (60 km south-south-west; open 1967–1974 Banksia Banksia elderiana Tall Shrubland (JK39). Between and 2000–2017) (data from www.bom.gov.au), provide a the two, moving from woodland to mallee lie narrow strips basis from which climatic conditions can be deduced by of Mixed Eucalyptus Low Woodland (JK46), York Gum averaging data from these two weather stations. The E. loxophleba Mallee (JK8a) and Spinifex Wattle Acacia study site experiences warm winters and hot summers coolgardiensis Tall Shrubland (JK37). To the north-east where January is the hottest month of the year (mean again, looking reddish, lies a mix of Mixed Eucalyptus Low Woodland (JK46) surrounding large patches of Salmon minimum 19.4°C, maximum 35.4°C) and July is the Gum Woodland (JK44) and moderate-sized patches of coldest month (mean minimum 4.7°C, maximum 17.0°C). York Gum Mallee (JK8a). North of these woodlands and The average annual rainfall is 278 mm and is relatively mallees, looking primarily green, lies Acacia aff.aneura Tall evenly distributed throughout the year with slightly more Shrubland (JK10) around Pittosporum Rock surrounding rain falling in summer (November–April) than in winter tiny patches of Granite Complex (JK15) and these are also (May–October). Winter rain consists mainly of small falls the primary vegetation types around Kurrajong Rock to the east. In between Pittosporum and Kurrajong Rocks, associated with the passage of cold fronts that are fairly darkish red in colour, lies the Hunt Range vegetated with regular in occurrence. Summer rainfall derives mainly from Cleland’s Blackbutt E. clelandiorum Low Woodland (JK41). thunderstorms or former tropical cyclones and tends to be Imagery: ZoomEarth sporadic and unreliable. There are five landform types in the study area (see E. ebbanoensis Mallee (JK18) and Yilgarn Banksia Banksia Figure 3 in Dell et al. 1985). The Helena and Aurora arborea Tall Shrubland (JK21). The Granite Outcrops are Ranges are a Banded Ironstone Formation, and the Hunt vegetated by Acacia aff.aneura Tall Shrubland (JK10) and Range between Pittosporum Rock and Kurrajong Rock is a Granite Complex (JK15).