|Scientific Name:||Pseudomys novaehollandiae (Waterhouse, 1843)|
No subspecies are recognised for Pseudomys novaehollandiae. Ford (2003) found that the genetic distinctiveness of P. novaehollandiae from P. delicatulus was no greater than that among individuals of P. delicatulus. He suggested that the two may not be separate species and that P. novaehollandiae may be a subspecies of P. delicatulus.
|Red List Category & Criteria:||Vulnerable B2ab(ii,iii,iv,v) ver 3.1|
|Assessor(s):||Woinarski, J. & Burbidge, A.A.|
|Contributor(s):||Wilson, B., Quin, B., Atkin, B., Menkhorst, P. & Quin, D.|
The New Holland Mouse has a small area of occupancy (680 km² across its entire known range, but only around 420 km² if only those sites where the species has been confirmed as present between 1999 and 2009 are included). Its geographic range is severely fragmented and there is a continuing decline in area of occupancy, habitat, number of locations and number of mature individuals. Currently it is assessed as Vulnerable.
|Previously published Red List assessments:|
The New Holland Mouse is a small, nocturnal, terrestrial, burrowing native rodent found in a disjunct and highly fragmented coastal and near coastal locations in southern Queensland, New South Wales, Victoria and Tasmania, including Flinders Island (Hocking and Driessen 2000, Kemper and Wilson 2008) and Hummock Island (Norris et al. 1979). It has been found from coastal areas and up to 100 km inland (Wilson and Laidlaw 2003) and from sea level up to around 900 m above sea level (Menkhorst et al. 2008). Its extent of occurrence (EOO) and area of occupancy (AOO) have been estimated at 108,000 km² and 680 km² respectively (TSSC 2010b). However, including only sites from which the species has been confirmed as present between 1999 and 2009, the EOO was estimated to be ca 90,000 km², and the AOO was estimated to be around 420 km² (TSSC 2010b). The distribution of recent subfossils further suggests that the species has undergone a large range contraction since European settlement (Breed and Ford 2007). At a regional level, there are several areas from which the species has disappeared since European settlement (Wilson 1996).
Native:Australia (New South Wales, Queensland, Tasmania, Victoria)
|Range Map:||Click here to open the map viewer and explore range.|
There is no robust estimate of population size nor that of most subpopulations; however, there are probably fewer than 10,000 mature individuals (Menkhorst et al. 2008). Abundance varies with location and vegetation condition. New Holland Mice peak in abundance in autumn and have lowest abundance in spring (Kemper and Wilson 2008). At Anglesea, Victoria, population density at 10-20 individuals ha-1 during early 1995, with decline to 3-10 ha-1 in June 1995 (Wilson 1991, Lock and Wilson 1999, Lock 2005). The abundance of New Holland Mice varies with location, vegetation and fire history (see the Habitats and Ecology section).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
The New Holland Mouse is a small, nocturnal, native rodent and is an opportunistic omnivore, consuming seeds, stem and leaf tissues, roots, fungi, insects and other invertebrates (Cockburn 1980, Norton 1987, Wilson and Bradtke 1999, Fox and Fox 2006). The introduced House Mouse Mus musculus has been shown to compete for food in some studies, but may be more insectivorous than the New Holland Mouse (Cockburn 1980). New Holland Mice live communally in burrows, emerging at night to feed.
New Holland Mice are mostly associated with early to mid stages of vegetation succession following fire. In a study in Victoria, they occurred most frequently in vegetation that had been burnt 3-4 years previously (Wilson 1991); while in Tasmania Pye (1991) recommended that to maintain a population at Mt William National Park, regular firing of the habitat, either naturally or by regular controlled patch-burn firing at intervals of 7-10 years was required. However, in Tasmania, the species has been found in vegetation of up to 16 years post-fire (DPIW 2010).
The subpopulation of New Holland Mice found in 1993 on the Yanakie Isthmus of Wilsons Promontory National Park, Victoria, was occupying atypical habitat – vegetated sand dunes that had not been burnt for 20-30 years. The dune habitat comprised a mature Banksia – Allocasuarina woodland with an understorey dominated by sedges and low shrubs (Quin 1996, Quin and Williamson 1996). Three years later, New Holland Mice had spread into adjacent open swales with a shrub layer of Coast Tea-tree Leptospermum laevigatum regenerating after being slashed within the previous three years (Atkin and Quin 1999). However, Coast Tea-tree and Coastal Wattle Acacia sophorae invasion of dunes was believed to threaten the ongoing existence of New Holland Mouse on the dunes because the resulting monoculture out-competed the vegetation community they preferred. Quin and Williamson (1996) and Atkin and Quin (1999) provided recommendations for the short-term management of the New Holland Mouse and its habitat and for further determining the impact of successional vegetation changes, including the effects of slashing and grazing, on New Holland Mouse numbers.
There is evidence that populations of the New Holland Mouse are strongly impacted by rainfall. Subpopulations in New South Wales have been shown to increase the length of their breeding season, and thus reproductive output, during times of above average rainfall (Kemper 1976, 1980). Maximum population densities at Anglesea, Victoria were recorded following four years of above average rainfall and declined during below average rainfall and drought conditions (Lock 2005, Wilson et al. 2007) and there is evidence that population fluctuations at Wilsons Promontory have been influenced by rainfall patterns (Wilson et al. 2005). At Anglesea abundance was found to have a strong positive relationship to cumulative monthly residual rainfall exhibiting a 0-9 month lag time (Lock 2005). It is likely that the impact of rainfall is related to its influence on resource availability that can lead to variations in reproductive output such as births, recruitment, and adult survival.
At Anglesea in Victoria, juveniles were captured from January to March (Wilson 1991) and the breeding season at Wilsons Promontory, Victoria was from December to May (Wilson et al. 2005). The longer breeding season of the New Holland Mouse in New South Wales means that females are capable of having up to six litters per season, while Victorian and Tasmanian subpopulations may have only 1-2 litters (Kemper 1990). The longer breeding season also means that first year females can breed, but this is not the case at Anglesea or in Tasmania (Norton 1987, Wilson 1991).
In New South Wales, breeding occurs between August and March with some variation between years. A study in New South Wales found that mean litter size was 4.6 (range 2-6) (Kemper 1980). In Tasmania, breeding is also seasonal and takes place from early November to late March and females are capable of producing at least two litters in a breeding season (Pye 1991).
In a laboratory study, sexual maturity was earlier in females, at 13 weeks, than in males (20 weeks) (Kemper 1976). In the wild, females may live up to two years, occasionally three. Generation length is here assumed to be 1.5 years.
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Generation Length (years):||1.5|
|Movement patterns:||Not a Migrant|
|Use and Trade:||New Holland Mice is not utilized.|
Threats to New Holland Mouse include:
There is no national recovery plan for this species; however, there is a Victorian Action Statement (Seebeck et al. 1996).
There is no species-specific management. New Holland Mice occur in several national parks and other conservation reserves with fire management, sometimes aimed at creating habitat for New Holland Mouse (e.g., Gippsland Lakes Coastal Park).
|Citation:||Woinarski, J. & Burbidge, A.A. 2016. Pseudomys novaehollandiae. The IUCN Red List of Threatened Species 2016: e.T18552A22398752.Downloaded on 19 November 2017.|
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