Greater stick-nest rat

The greater stick-nest rat (Leporillus conditor), also known as the housebuilding rat[4] and wopilkara,[5] is a species of rodent in the family Muridae. They are about the size of a small rabbit and construct large nests of interwoven sticks. Once widespread across southern Australia, the population was reduced after European colonisation to a remnant outpost on South Australia's Franklin Islands. The species has since been reintroduced to a series of protected and monitored areas, with varying levels of success.[6]

Greater stick-nest rat
CITES Appendix II (CITES)[2]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Muridae
Genus: Leporillus
Species:
L. conditor
Binomial name
Leporillus conditor
(Sturt, 1848)[3]

Taxonomy

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A description of the species was given in a report of the explorer Charles Sturt, and published in 1848.[3][7] The species was placed as genus Mus, and later assigned to Leporillus, and so allied to the murid family of rodents. The type was collected in vegetation on the Darling River, around 45 miles from Laidley Ponds, the disposition of this specimen is unknown.[7]

Description

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The species has a broad and short head, with wide and rounded ears. The length of the head and body combined in 190 to 260 millimetres, and a tail noticeably shorter than that, measuring from 148 to 180 mm. The weight ranges from 190 to 450 grams. The pelage is a uniform grey-brown colour at the upper-side, the buff to grey beneath is paler and the two colours blend where they meet. The visible parts of the foot are whitish at the inside and greyish brown at the outside, this is from 42 to 48 mm in length. The female possesses four teats, two pairs at the inguinal region.[8]

Behaviour

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The behavioural description is of a passive and gentle species, largely active at night, with a herbivorous diet largely composed of succulent leaves. The 'nest' of L. conditor is sited at a cave, rocky outcrop or over a shrub, the construction reaching a metre in height and around two metres in width. The larger part of the nest is tightly woven from sticks, the inner part is built from softer grassy material.[8]

Ownership of nests appears typically to be passed down through relatively sedentary, genetically related female lines, with males typically distributing throughout the landscape at sexual maturity.[9]

Mainland populations were reported in historical accounts to prefer building nests over slight depressions in the ground or above the burrows of other animals, which were used as escape routes. Some animals were known to weight their nests with small rocks.[10][11][12] Nests were reported to be strong and secure enough to repel dingos and other predators.[12]

Breeding may occur throughout the year, although most often recorded during the austral spring, April to May, and they produce a litter of between one and four young.[8]

The population on Reevesby Island is highly associated with the invasive exotic weed African boxthorn, which provides shelter from predators due to its thorny foliage, and food in the form of leaves and fruit.[13]

Distribution and habitat

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The species' natural habitat is dry savanna, with perennial shrubland, especially of succulent and semi-succulent plant species including the chenopod and pig-face genera.[14]

It was formerly widespread in semi-arid habitat on the mainland,[15] where the soils were shallow with calcareous underlying strata.[16] Before the sharp decline in population in the late nineteenth century, the species was found south of a line from Shark Bay to the meeting of the rivers at the Murray–Darling basin and above the 28° southern latitude.

The drastic reduction in the range of this mammal is associated with the collapse of mammalian fauna in Australia between about 1875 and 1925, which is often linked to the decline of aboriginal land management and burning practices, widespread land clearance and agriculture, the introduction of foreign grazing animals including sheep, cattle and rabbits, and invasions by exotic predators like the European red fox and feral cats. The susceptibility of this species to a theorised epizootic event, an unidentified disease spreading from Western Australia, was estimated to be high in modelling of mammal's relative immunity.[17]

The drastic contraction of the distribution range continued until the species could only be found on the Franklin Islands in the Nuyts Archipelago, and from this population the species was reintroduced to protected areas on the mainland and other islands.[8]

Reintroductions and conservation programs

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There are introduced or reintroduced populations established on St Peter Island in the Nuyts Archipelago, Reevesby Island and Salutation Island.[18]

A reintroduced population at Arid Recovery, a fenced reserve at Roxby Downs in South Australia, persisted for over 20 years,[19] but is now believed to be locally extinct, following periods of drought, high temperatures and degradation of food plants by over-abundant burrowing bettongs.[20]

The outcome of a series of translocations to the fenced Mount Gibson Sanctuary in Western Australia is undetermined.[6] However, in August 2024 the population was assessed as "close to local extinction" following dry summer conditions in 2023-24.[21]

Reintroduction attempts began at a fenced landscape within NSW's Mallee Cliffs National Park in September 2020,[22] with the species observed as persisting during formal monitoring in 2023.[23] The species was reintroduced to Dirk Hartog Island in May 2021, with early monitoring suggesting ongoing survival.[24][25][26]

A high proportion of reintroduction attempts for the species have not been successful.[27] Attempts to reintroduce the species failed at Faure Island and Heirisson Prong in Western Australia, at Yookamurra Sanctuary and Venus Bay Conservation Park in South Australia, and at Scotia Sanctuary and Sturt National Park in NSW.[28][29]

Most failures have been blamed on inadequate habitat, food or release protocols, or excessive predation by monitors, raptors or feral cats.[6] Hyperdispersal and stress responses due to the presence of predatory goannas were blamed for the failure of the reintroduction on Faure Island.[6]

The catastrophic loss of animals at Sturt National Park — where 75% of the reintroduced rats died within just five days of release — was provisionally blamed on the site's microclimate differing from the rats' origin point, Reevesby Island.[30] This was speculated to have contributed to dehydration, stress and malnutrition among the animals, despite the provision of supplementary wet food.[30] However, it was also acknowledged that the reintroduction site hosts high densities of the predatory crest-tailed mulgara, which had been reintroduced to the site first, on the assumption the predators would not be a threat to the rats.[30]

The species is currently being bred in captivity at Monarto Safari Park and Adelaide Zoo, with progeny provided to reintroduction projects.[31] Individuals from a captive population at Taronga Zoological Park have been used in research to improve the knowledge of health data of those in captivity.[32]

References

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  1. ^ Woinarski, J.; Burbidge, A.A. (2016). "Leporillus conditor". IUCN Red List of Threatened Species. 2016: e.T11634A22457522. doi:10.2305/IUCN.UK.2016-2.RLTS.T11634A22457522.en. Retrieved 12 November 2021.
  2. ^ "Appendices | CITES". cites.org. Retrieved 14 January 2022.
  3. ^ a b Sturt, C. (1848). Narrative of an Expedition into Central Australia (transcript). Vol. 1. London: T & W Boone. p. 120.
  4. ^ "Stick-nest rat, house building rat (Leporillus conditor) / Australian National Parks and Wildlife Service". Trove. 18 October 2020.
  5. ^ "Greater Stick-nest Rat - profile | NSW Environment, Energy and Science". www.environment.nsw.gov.au. Retrieved 18 October 2020.
  6. ^ a b c d Short, Jeff; Copley, Peter; Ruykys, Laura; Morris, Keith; Read, John; Moseby, Katherine (8 October 2019). "Review of translocations of the greater stick-nest rat (Leporillus conditor): lessons learnt to facilitate ongoing recovery". Wildlife Research. 46 (6): 455–475. doi:10.1071/WR19021. ISSN 1448-5494. S2CID 203389727.
  7. ^ a b Musser, G. G.; Carleton, M. D. (2005). "Superfamily Muroidea". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 894–1531. ISBN 978-0-8018-8221-0. OCLC 62265494.
  8. ^ a b c d Menkhorst, P.W.; Knight, F. (2011). A field guide to the mammals of Australia (3rd ed.). Melbourne: Oxford University Press. p. 208. ISBN 9780195573954.
  9. ^ Onley, Isabelle (8 May 2022). "Meet the territorial females and matriarchs in Australia's backyard". The Conversation. Retrieved 10 May 2022.
  10. ^ "Our Curious Animals". Chronicle (Adelaide, SA : 1895 - 1954). 24 January 1935. p. 64. Retrieved 8 September 2020.
  11. ^ "A RAT-HOUSE". World's News (Sydney, NSW : 1901 - 1955). 19 July 1952. p. 30. Retrieved 8 September 2020.
  12. ^ a b "JERBOA RAT". Courier-Mail (Brisbane, Qld. : 1933 - 1954). 3 March 1934. p. 21. Retrieved 8 September 2020.
  13. ^ "How this tiny native rat on the brink of extinction is thriving on an island infested with snakes". ABC News. 26 July 2024. Retrieved 29 July 2024.
  14. ^ "The Action Plan for Australian Rodents". Department of the Environment. 1 April 1995. Retrieved 24 December 2015.
  15. ^ Ellis, M. (1995). A discussion of the large extinct rodents of Mootwingee National Park, western New South Wales. Australian Zoologist. 30:1-4.
  16. ^ Josephine Flood (2004) Archaeology of the Dreamtime, J.B Publishing, Marleston p. 206 ISBN 1-876622-50-4
  17. ^ Abbott, I. (December 2006). "Mammalian faunal collapse in Western Australia, 1875-1925: the hypothesised role of epizootic disease and a conceptual model of its origin, introduction, transmission, and spread". Australian Zoologist. 33 (4): 530–561. doi:10.7882/az.2006.024. ISSN 0067-2238.
  18. ^ "Greater stick-nest rat - Leporillus conditor - ARKive". Archived from the original on 22 January 2010. Retrieved 14 March 2010.
  19. ^ "Arid Recovery - Greater Stick-nest Rat". aridrecovery.org.au. Retrieved 23 September 2024.
  20. ^ "Arid Recovery Annual Report 2022-2023" (PDF). Arid Recovery Annual Reports. Archived from the original (PDF) on 1 September 2024.
  21. ^ Sinclair, Anderson, Callander, Bourne, Sitters, Joseph, Kanowski (2024). "Eco-Health Report 2023: Mt Gibson Sanctuary" (PDF). Australian Wildlife Conservancy.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  22. ^ "Stick-nest building mammal back in the Mallee". AWC - Australian Wildlife Conservancy. 28 October 2020. Retrieved 11 November 2020.
  23. ^ Ladd, Holding, Booth-Remmers, Hornstra, Joseph, Holland, Kanowski (2023). "Eco-Health Report 2022-2023: Mallee Cliffs" (PDF). Australian Wildlife Conservancy.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  24. ^ Parks and Wildlife Service, Western Australia - Greater stick-nest rats released onto Dirk Hartog Island | Facebook, retrieved 2 September 2021
  25. ^ "Ground-breaking return of native rodents to Dirk Hartog Island". 2 September 2021. Archived from the original on 2 September 2021. Retrieved 2 September 2021.
  26. ^ Cowen, Saul; Rayner, Kelly; Sims, Colleen; (1 July 2021). Dirk Hartog Island National Park Ecological Restoration Project : Stage Two–Year Three Translocation and Monitoring Report
  27. ^ Onley, I. R.; White, L. C.; Moseby, K. E.; Copley, P.; Cowen, S. (18 August 2022). "Disproportionate admixture improves reintroduction outcomes despite the use of low-diversity source populations: population viability analysis for a translocation of the greater stick-nest rat". Animal Conservation. 26 (2): 216–227. doi:10.1111/acv.12812. ISSN 1367-9430. S2CID 251685412.
  28. ^ "Reintroducing locally extinct mammals to Sturt National Park | Centre for Ecosystem Science". www.ecosystem.unsw.edu.au. Retrieved 3 September 2020.
  29. ^ "These native species were locally extinct but are now reclaiming their desert homeland". ABC News. 21 September 2024. Retrieved 22 September 2024.
  30. ^ a b c "Wild Deserts Newsletter #10 - August 2023". 27 July 2024. Archived from the original on 27 July 2024. Retrieved 22 September 2024.
  31. ^ "Fluffy stick-nest rats born at Monarto Safari Park as part of conservation program". Monarto Safari Park. 18 September 2020. Retrieved 20 September 2020.
  32. ^ Tulk, Melissa L.; Stannard, Hayley J.; Old, Julie M. (2 September 2016). "Haematology and serum biochemistry in captive Australian native murids: black-footed tree-rat (Mesembriomys gouldii) and greater stick-nest rat (Leporillus conditor)". SpringerPlus. 5 (1): 1479. doi:10.1186/s40064-016-3111-7. ISSN 2193-1801. PMC 5010547. PMID 27652053.