Survey guidelines for Australia’s threatened non-flying mammals

2.2Grouping mammals according to body size and survey methods

The methods used to detect non-flying mammals during field surveys can be grouped according to the target species’ body size and the nature of their ecology. In general, direct evidence (such as an animal in the hand or visual observation by an experienced investigator) provides the most unequivocal evidence of species presence, and most survey methods are designed around these approaches. Survey methods designed to detect mammalian fauna by direct evidence include capture techniques, diurnal observation, and spotlight survey. Signs of fauna activity, such as diggings in the ground, scratches on tree trunks, burrows, nests, dens, scats and tracks can provide indirect evidence of a species’ presence, especially if the sign is species-specific. Where signs are detected, but are not sufficient to distinguish between species, then direct survey methods targeting the locations where signs of fauna activity were detected are required to provide a definite species identification.
There are a large number of biological and ecological factors that influence how visible a species is in the field and in turn how easily it is detected, including:

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  body size and other morphological characteristics (for example, fur colour, distinctive markings, brightness of eye shine)
  
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  behaviour (for example, vocalisations, displays, flight, home range size, diet and foraging activity, ease of capture, use of nests, dens or burrows)
  
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  sociality (for example, whether individuals are solitary or gregarious)
  
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  activity patterns (diurnal, nocturnal, crepuscular, seasonal, climatic or longer term environmental effects such as rainfall, which relate to breeding and hibernation)
  
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  habit (ground-dwelling, arboreal or scansorial)
  
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  habitat (for example, structure and density of vegetation, or physical attributes of the topography such as steepness of slope, rocky outcrops or boulders, gullies or caves)
  
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  abundance (common or rare within an area).
  

Taking into account the above factors, species that are likely to be the most visible in the field are those that are large and conspicuous, possibly gregarious, active during the day, ground-dwelling, inhabit an open terrain (for example, grasslands) and relatively common. Examples of this type of species in Australia are found within the large kangaroo species (Macropus genus). In contrast, the majority of the non-flying mammal species listed under the EPBC Act are small or medium in body size, nocturnal, inhabit rugged, remote or densely vegetated habitats, and by the nature of their limited abundance and restricted distributions are considered rare. Of the large-sized species listed, which includes the Barrow Island euro, Macropus robustus isabellinus, the rock wallabies Petrogale spp., the wombats and the quolls, detection is limited by the rugged habitats in which the species live or (in the case of the quolls and the wombats) their nocturnal activity patterns.

All of the non-flying mammals listed on the EPBC Act have been grouped into one of four classes (Table 1) according to body size and habit, which directly relate to appropriate survey methods for detection. Three body weight classes (small, medium and large) are defined. Arboreal species are grouped as a distinct class, because although this group includes both small and medium-sized species, the appropriate survey methods for detecting arboreal mammals are similar. The average adult body weights are taken or calculated from male and female averages provided in published literature that is referenced in the species profiles. The body weight classes are not exclusive and have been used as a guide to group species according to appropriate survey methods, hence some species fall outside the defined weight range. For example, the chuditch or western quoll, Dasyurus geoffroii, and northern quoll, D. hallucatus, weigh on average less than the large-sized species minimum weight of 3000 grams, yet have been included with the other quolls in the large-sized class because of similarity in appropriate survey methods (Table 1).

The four non-flying mammal classes used in this report are:

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  large-sized ground-dwelling mammals – includes species with an average adult body weight greater than 3000 grams
  
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  medium-sized ground-dwelling mammals – includes species with an average adult body weight between 300–3000 grams
  
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  arboreal mammals with an average adult body weight between 50–500 grams
  
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  small-sized ground-dwelling mammals – includes species with an average adult body weight between 10–300 grams.
  

Large-sized ground-dwelling mammals include two wombat species, one kangaroo, ten wallabies, the quokka, Tasmanian devil and four species of quoll (Table 1). These species are almost entirely ground-dwelling, however, quolls can climb trees and rock wallabies inhabit very rugged terrain that differs from most of the other listed ground-dwelling species. All of the species are primarily nocturnal. However, they generally become active at dusk and all can exhibit activity during daylight hours to some degree, particularly during the winter months (see species profiles for details).

The medium-sized ground-dwelling mammals include the numbat, greater bilby, boodie, woylie, seven bandicoot species, three potoroos, three bettongs and five species of hare-wallabies (Table 1). With the exception of the numbat, these species are all nocturnal and shelter during the day in nests, burrows, hollow logs or dense vegetation on the ground.
The small and medium-sized arboreal species are a diverse assemblage of seven primarily arboreal mammals (Table 1). They include the red-tailed phascogale, two possum species, two gliders and two rats, the brush-tailed rabbit rat (which is both tree and ground-dwelling) and the golden-backed tree rat, which, based on very limited information, appears to be primarily arboreal (see species profile).
The small-sized ground-dwelling mammal class contains a diverse range of species including a shrew, a pygmy possum, marsupial moles, 10 Dasyuridae species and 14 native rodents. This class includes species from a wide range of ecosystems (for example, the arid zone of central Australia and alpine regions of Victoria and New South Wales). Despite this diversity of habitat, survey methods typically used to detect these species are similar.
The classes have been used here to group species according to similar survey methods and differ from the classes used by Burbidge and McKenzie (1989) and Short and Smith (1994) to define mammal size classes in terms of a critical weight range for medium-sized, non-flying mammals between 35 and 5500 grams. Burbidge and McKenzie (1989) demonstrated that mammals within the critical weight range have disproportionately experienced a far greater rate of extinction in Australia since European settlement than other mammals. When the non-flying mammals listed under the EPBC Act are considered in terms of the critical weight range, 74 per cent fall within this range (note that species with male weights over 5500 grams were not included in the calculation).
Table 1. Threatened non-flying mammal species listed on the EPBC Act as at July 2010 classified according to body weight and habit.

Family	Scientific name	Common name	EPBC Act status
Large-sized ground-dwelling species (average body weight > 3000 g)
Vombatidae	Vombatus ursinus ursinus	Common wombat (Bass Strait)	Vulnerable
	Lasiorhinus krefftii	Northern hairy-nosed wombat	Endangered
Macropodidae	Macropus robustus isabellinus	Barrow Island euro	Vulnerable
	Setonix brachyurus	Quokka	Vulnerable
	Petrogale lateralis	Black-footed rock wallaby (West Kimberley race)	Vulnerable
	Petrogale lateralis	Black-footed rock wallaby (MacDonnell Ranges race)	Vulnerable
	Petrogale lateralis lateralis	Black-flanked rock wallaby	Vulnerable
	Petrogale lateralis hackettii	Recherche rock wallaby	Vulnerable
	Petrogale penicillata	Brush-tailed rock wallaby	Vulnerable
	Petrogale persephone	Proserpine rock wallaby	Endangered
	Petrogale xanthopus xanthopus	Yellow-footed rock wallaby	Vulnerable
	Onychogalea fraenata	Bridled nailtail wallaby	Endangered
	Macropus eugenii eugenii	Tammar wallaby	Extinct
Dasyuridae	Dasyurus geoffroii*	Chuditch or western quoll	Vulnerable
	Dasyurus maculatus gracilis	Spotted-tailed quoll or yarri (north Queensland)	Endangered
	Dasyurus maculatus maculatus	Spotted-tailed quoll (SE mainland population) Spotted-tailed quoll (Tasmanian population)	Endangered Vulnerable
	Dasyurus hallucatus	Northern quoll	Endangered
	Sarcophilus harrisii	Tasmanian devil	Endangered
Medium-sized Ground-dwelling Species (average body weight range approx. 300-3000 g)
Dasyuridae	Myrmecobius fasciatus	Numbat	Vulnerable
Peramelidae	Perameles bougainville bougainville	Western barred bandicoot (Shark Bay)	Endangered
	Isoodon auratus auratus	Golden bandicoot (mainland)	Vulnerable
	Isoodon auratus barrowensis	Golden bandicoot (Barrow Island)	Vulnerable
	Isoodon obesulus obesulus	Southern brown bandicoot	Endangered
	Isoodon obesulus nauticus	Southern brown bandicoot (Nyuts Archipelago)	Vulnerable
	Perameles gunnii gunnii	Eastern barred bandicoot (Tasmania)	Vulnerable
	Perameles gunnii unnamed subsp.	Eastern barred bandicoot (mainland)	Endangered
	Macrotis lagotis	Greater bilby	Vulnerable
Potoroidae	Bettongia tropica	Northern bettong	Endangered
	Bettongia lesueur lesueur	Boodie or burrowing bettong (Shark Bay)	Vulnerable
	Bettongia lesueur unnamed subsp.	Boodie or burrowing bettong (Barrow and Boodie Islands)	Vulnerable
	Bettongia lesueur graii	Boodie or burrowing bettong (inland subspecies)	Extinct
	Bettongia penicillata ogilbyi	Woylie	Endangered
	Potorous gilbertii	Gilbert's potoroo	Critically Endangered
	Potorous longipes	Long-footed potoroo	Endangered
	Potorous tridactylus tridactylus	Long-nosed potoroo (South-east mainland)	Vulnerable
Macropodidae	Lagorchestes hirsutus bernieri	Rufous hare wallaby (Bernier Island)	Vulnerable
	Lagorchestes hirsutus dorreae	Rufous hare wallaby (Dorre Island)	Vulnerable
	Lagorchestes hirsutus unnamed subsp.	Rufous hare wallaby (central mainland) or mala	Endangered
	Lagorchestes conspicillatus conspicillatus**	Spectacled hare wallaby (Barrow Island)	Vulnerable
	Lagostrophus fasciatus fasciatus	Banded hare wallaby (Marnine Munning)	Vulnerable
Small & Medium-sized Arboreal Species (average body weight range approx. 100-500 g)
Petauridae	Gymnobelideus leadbeateri	Leadbeater's possum	Endangered
	Petaurus australis unnamed subsp.	Fluffy glider or yellow-bellied glider (wet tropics)	Vulnerable
	Petaurus gracilis	Mahogany glider	Endangered
Pseudocheiridae	Pseudocheirus occidentalis	Western ringtail possum	Vulnerable
Muridae	Mesembriomys macrurus	Golden-backed tree rat	Vulnerable
	Conilurus penicillatus	Brush-tailed rabbit rat	Vulnerable
Dasyuridae	Phascogale calura	Red-tailed phascogale	Endangered
Small-sized Ground-dwelling Species (average body weight range approx. 10-300 g)
Croidurine	Crocidura attenuata trichura	Christmas Island shrew	Endangered
Notoryctidae	Notoryctes caurinus	Northern marsupial mole or Karkarratul	Endangered
	Notoryctes typhlops	Southern marsupial mole or Yitjarritjarri	Endangered
Burramyidae	Burramys parvus	Mountain pygmy possum	Endangered
Dasyuridae	Sminthopsis butleri	Carpentarian dunnart	Vulnerable
	Sminthopsis griseoventer boullangerensis	Boullanger Island dunnart	Vulnerable
	Sminthopsis aitkeni	Kangaroo Island dunnart	Endangered
	Sminthopsis psammophila	Sandhill dunnart	Endangered
	Sminthopsis douglasi	Julia Creek dunnart	Endangered
	Pseudantechinus mimulus	Carpentarian antechinus	Vulnerable
	Parantechinus apicalis	Dibbler	Endangered
	Dasycercus byrnei	Kowari	Vulnerable
	Dasycercus cristicauda	Mulgara	Vulnerable
	Dasycercus hillieri	Ampurta	Endangered
Muridae	Pseudomys pilligaensis	Pilliga mouse	Vulnerable
	Pseudomys fieldi	Shark Bay mouse or djoongari	Vulnerable
	Pseudomys australis	Plains rat	Vulnerable
	Pseudomys fumeus	Smoky mouse or konoom	Endangered
	Pseudomys shortridgei	Dayang or heath rat	Vulnerable
	Pseudomys oralis	Hastings River mouse	Endangered
	Notomys aquilo	Northern hopping mouse	Vulnerable
	Notomys fuscus	Dusky hopping mouse or wilkiniti	Vulnerable
	Xeromys myoides	False water rat	Vulnerable
	Zyzomys pedunculatus	Central rock rat	Endangered
	Zyzomys palatalis	Carpentarian rock rat	Endangered
	Zyzomys maini	Arnhem Land rock rat	Vulnerable
	Melomys rubicola	Bramble Cay melomys	Endangered
	Leporillus conditor***	Greater stick-nest rat or wopilkara	Vulnerable

* The chuditch Dasyurus geoffroii and the northern quoll Dasyurus hallucatus weigh on average less than 3000 grams.

** The spectacled hare wallaby (Barrow Island) Lagorchestes conspicillatus conspicillatus weighs on average more than 3000 grams.

*** The greater stick-nest rat Leporillus conditor weighs on average more than 300 grams.