Common wombat (Bass Strait)
Vombatus ursinus ursinus
States and territories: Bass Strait, Tasmania.
Regions: Flinders Island.
Habitat: Open woodland.
Habit: Ground-dwelling (burrows).
Avg. body weight: Species average is 26 kg (McIlroy 1995), but the Flinders Island wombats are the smallest subspecies.
Activity pattern: Nocturnal/partly diurnal.
Diet: Herbivore: native grasses, sedges, rushes and the roots of trees and shrubs (McIlroy 1995).
Breeding: The species is reported to be capable of breeding at any time of the year (McIlroy 1995).
Description
Wombats are ground-dwelling herbivorous marsupials that forage mainly at night and rest in burrows during the day. A number of burrows (number varies) are constructed throughout an individual’s home range area, with reports of up to 13 different burrows used over several weeks (McIlroy 1995). Signs of burrow entrances and piles of large distinctively square/rectangular shaped droppings are reliable signs of wombat activity within an area.
The Bass Strait wombat survives on Flinders Island in Bass Strait. The extinction of wombats on other Bass Strait Islands prior to 1910 has been attributed to hunting by sealers and settlers, and loss of habitat to agriculture (Bryant & Jackson 1999). Bass Strait wombats are slightly smaller than wombats from the mainland (Bryant & Jackson 1999), which are on average 26 kilograms and head-body length 98.5 centimetres (McIlroy 1995). No genetic studies have been published on this species (DEWHA 2009).
Survey methods
On the basis of previous surveys, the following survey techniques are recommended to detect the presence of the Bass Strait wombat in areas up to 5 hectares in size:
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daytime searches for potentially suitable habitat resources, such as open woodland (description of the survey technique and recommended effort is outlined in Section 3.1)
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daytime searches for signs of activity, including community records, burrows, tracks and scats (description of the survey technique and recommended effort is outlined in Section 3.2)
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possibly spotlight surveys (description of the survey technique and recommended effort is outlined in Section 3.3.3), or observation surveys conducted at potentially active burrows to identify wombats emerging to forage (description of the survey technique and recommended effort is outlined in Section 3.3.4).
Trapping surveys are not considered necessary to determine the presence of the Bass Strait wombat from a subject site. If aerial surveys are undertaken, they should be conducted in association with ground-based daytime searches.
Similar species in range
There are no species similar in appearance to the Bass Strait wombat within the species’ known range.
References
Bryant, S. and Jackson, J. 1999. Tasmania's Threatened Fauna Handbook: What, where and how to protect Tasmania's threatened animals. Threatened Species Unit, Parks and Wildlife Tasmania.
DEWHA 2009. Common Wombat (Bass Strait) Vombatus ursinus ursinus. Department of Environment, Water, Heritage and the Arts.
www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=66650 (last accessed 4/11/09)
McIlroy, J.C. 1995. Common Wombat Vombatus ursinus. In ‘The Mammals of Australia’. (Ed. R. Strahan) pp. 204-205 (Reed Books: Sydney).
St. John, B.J. and Saunders, G.M. 1989. Plan of Management for the Hairy-nosed Wombat in South Australia. Unpublished report for the National Parks and Wildlife. Department of Environment and Planning South Australia.
Dayang, heath rat
Pseudomys shortridgei
States and territories: Victoria, South Australia and Western Australia.
Regions: South-western Victoria, adjacent parts of South Australia, possibly Kangaroo Island, the Fitzgerald River National Park and three sites in the southern wheatbelt of Western Australia (Menkhorst et al. 2008).
Habitat: Species-rich dry heathland that has been burnt within the last five to 15 years and stringybark open forests with a heathy understorey up to 25 years post fire; also heathland with the highest densities 30 years post fire, mixed scrub and mallee in Western Australia (Menkhorst et al. 2008). Microhabitat preferences include floristically diverse sites that are capable of supplying year-round food, especially grasses, sedges and underground fungi during autumn and winter.
Habit: Ground-dwelling (Menkhorst et al. 2008).
Avg. body weight: 70 g (Menkhorst et al. 2008).
Activity pattern: Nocturnal (partly diurnal).
Diet: Generalist herbivore: flowers, fruit, stems and leaves; also supplemented with insects and the fruiting bodies of underground fungi (Watts and Braithwaite 1978).
Breeding: Breeding occurs between September and February but varies with ephemeral habitat (Cockburn et al. 1981).
Description
The dayang is a relatively large native rodent, distinguished by its grey-brown colour, brown feet, blunt face, and hairy, non-annulated tail (Menkhorst et al. 2008).
The dayang primarily inhabits heathlands that have been patchily burnt to create a mosaic of age classes including areas of high productivity. In Victoria the optimum age post fire is between 10 and 20 years, while in Western Australia it is in long unburnt heath (that is, 30 year post fire) with no individuals recorded in recently burnt heath (that is, less than 10 years post fire) (Menkhorst et al. 2008). The dayang colonise relatively recently burnt areas, temporarily increasing in abundance. When the habitat returns to the previous unproductive state, dayang disperse again to colonise another newly burnt area (Menkhorst et al. 2008). In addition to dispersal, the population density decreases at sites as the time since burning increases, because juvenile survival decreases in mature heathlands (Cockburn et al. 1981). Changes in burning regimes may be related to the decline in this species distribution, particularly as a result of increased fire frequencies and large-scale fires resulting in uniform vegetation ages (Menkhorst et al. 2008).
Survey methods
On the basis of previous surveys, the following survey techniques are recommended to detect the presence of the dayang in areas up to 5 hectares in size:
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investigation of key habitat characteristics through vegetation mapping, habitat modelling and aerial photography. Additionally, daytime searches for potentially suitable habitat resources such as heathlands comprising a mosaic of fire affected habitats (description of the survey technique and recommended effort is provided in Section 3.1)
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collection of predator scats, owl casts or remains in predatory bird/mammal nests/dens (description of the survey technique and recommended effort is provided in Section 3.2)
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hair sampling device surveys using a mixture of rolled oats, peanut butter, honey and pistachio nut oil (optional) for bait, conducted according to the description of the technique and the recommended effort outlined in section 3.3.7, as the dayang is included among those species distinguishable from hair samples (see Table 2, Section 3.3.7)
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Elliott A/E trapping surveys as a primary survey technique conducted according to the technique description and recommended effort provided in Section 3.3.9
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possibly pitfall trapping surveys (with trap depth recommended to be 60 centimetres) conducted according to the description of the technique and the recommended effort outlined in Section 3.3.8, as long as the habitat is suitable for the establishment of pitfall traps
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it is likely that camera traps would be extremely useful (see Section 3.3.6). This technique has not been trialled, although this species has been recorded incidentally in the Grampians with camera traps set for the smoky mouse (Nelson et al. 2009).
It is recommended that surveys designed to detect the presence of the dayang consider any historical records of the species from the locality in terms of habitat connectivity. An investigator should target optimum post-fire ages for the various habitats indicated above that occur within, or are connected to a subject site, or which occur within a radius of, for example, 5 kilometres. The purpose of such an approach is to target prime post-fire age habitats where the dayang will be at higher densities, and therefore more easily detected. The large home range of the species and its dependence on dispersal between prime post fire habitat patches means that its presence at a site needs to be considered from a landscape perspective.
Similar species in range
The dayang is sympatric with a number of other rodent species and may be confused in the field. It can be distinguished from the bush rat Rattus fuscipes by the colouration of the tail: the dayang has a tail that is dark brown above and light below, whereas the bush rat has a pinkish-brown tail. The dayang can be distinguished from the swamp rat Rattus lutreolus and the broad-toothed rat Mastacomys fuscus by long grey hairs on the upper surface of its feet compared to the short brown fur on the feet of the other two species (Menkhorst & Knight 2004). The dayang can also be distinguished from the smoky mouse by its tail to body ratio: the dayang’s tail length is less than its head and body length combined, whereas the smoky mouse is greater. Identification should be made by investigators familiar with the species’ appearance, such as from previous experience with live or voucher specimens.
References
Baynes, A., Chapman, A and Lynam, A.J. 1987. The rediscovery, after 56 years of the Heath Rat Pseudomys shortridgei (Thomas, 1907)(Rodentia: Muridae) in Western Australia. Records of the Western Australian Museum 13: 319-322.
Cockburn, A. R., W. Braithwaite and A.K. Lee 1981. The response of the Heath Rat, Pseudomys shortridgei to pyric succession: a temporally dynamic life-history strategy. Journal of Animal Ecology 50: 649-666.
Emison, W.B., Porter, J.W., Norris, K.C. and Apps, G.J. 1978. Survey of the vertebrate fauna of the Grampians-Edenhope area of southwestern Victoria. Memoirs of the National Museum of Victoria 39: 281-363.
Menkhorst, P. and Knight, F. 2004. A Field Guide to the Mammals of Australia. Second Edition. (Oxford University Press: Melbourne).
Menkhorst, P.W. and Beardsell, C.M. 1982. Mammals of southwestern Victoria from the Little Desert to the coast. Proceedings of the Royal Society of Victoria 94: 211-247.
Menkhorst, P.W., Cockburn, A. and Cancilla, D. 2008. Heath Mouse Pseudomys shortridgei. In ‘The Mammals of Australia’ (Eds. S. Van Dyck and R. Strahan). pp. 630-632. (Reed New Holland: Sydney).
Meulman, E.P. and Klomp, N.I. 1999. Is the Home Range of the Heath Mouse Pseudomys shortridgei an anomaly in the Pseudomys Genus? Victorian Naturalist 116(6): 196-201.
Nelson, J., Menkhorst, P., Howard, K., Chick, R. and Lumsden, L. 2009. The status of Smoky Mouse populations at some historic sites in Victoria, and survey methods for their detection. Arthur Rylah Institute for Environmental Research Unpublished report number 2009/17. Department of Sustainability and Environment, Heidelberg, Victoria
Quinlan, K., Moro, D. and Lund, M. 2004. Improving trapping success for rare species by targeting habitat types using remotely sensed data: a case study of the Heath Mouse (Pseudomys shortridgei) in Western Australia. 31: 219-227.
Seebeck, J.H. 1976. Mammals in the Pomonal area, the Grampians. Victorian Naturalist 93: 138-147.
Watts, C.H.S. and Braithwaite, R.W. 1978. The diet of Rattus lutreolus and five other rodents in southern Victoria. Australian Wildlife Research 5: 47-57.
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