Landscape ecology of house mouse outbreaks in south‐eastern Australia

Abstract

Summary 1.House mouse Mus domesticus outbreaks in the grain-growing areas of south-eastern Australia occur irregularly and may be local or widespread, covering thousands of square kilometres. All natural and agricultural habitats are occupied when house mouse numbers are high, and the question we addressed was whether we can distinguish source and sink habitats within these agricultural landscapes so that management practices can be better targeted. 2. Live-trapping on replicated grids in 15 habitats, including eucalypt woodland, cypress pine woodland, areas of permanent water and crop habitats, was carried out from 1983 to 1988 at 9-week intervals. 3. Agricultural cropland (including crops, fallow and pastures), farm buildings, seepage areas and natural woodland could be source habitats. Farm buildings, seepage areas and saltbush areas all had high mouse densities entering the 1983-84 outbreak and were refuge habitats for mice. 4. Cropland habitats quickly became the source area in spring 1983, and woodlands were initially sinks that lagged 2-4 months behind the population growth shown in crops. 5. Adult female mice in cropland habitats were more often in breeding condition compared with mice in natural woodland. Mice also had higher indices of residency in cropland than in natural woodland. 6. Synthesis and applications . In non-irrigated cereal production areas of south-eastern Australia, house mice move from refuge habitats in seepage areas and farm buildings into crops, build up in numbers in cropland habitats, and then invade woodland habitats, which by themselves cannot generate outbreaks of this pest species. Monitoring for incipient outbreaks should concentrate on refuges in seepage areas and crops and their associated fence lines as source habitat indicators. Population control in these habitats in spring would reduce the likelihood of population outbreaks in autumn, leading to reduced rodenticide use and a concomitant reduction in environmental hazards.

Episodic outbreaks of small mammals influence predator community dynamics in an east African savanna ecosystem

“…Greater complexity in a system generates less predictable responses of consumers to primary productivity spatially and temporally (Bonnet et al ), and productivity increases with species richness (Hooper et al ), so in principle, a lower rainfall threshold should be required for a species‐rich system to generate an outbreak, which is what we observed. Doubtless this complexity contributed to the low predictive power of our statistical models, a problem also encountered by Krebs et al () and Singleton et al () when quantifying house mouse outbreaks in Australian agricultural systems.…”

Influence of fire history on small mammal distributions: insights from a 100‐year post‐fire chronosequence

“…A similar result was found when M. domesticus models were tested on independent data. Mus domesticus populations are dynamic, and the abundance of this species changes dramatically in semi‐arid Australia owing to rainfall patterns (Singleton et al. , 2007).…”

Population dynamics of house mice without mammalian predators and competitors

“…In other ecosystems worldwide, house mouse population densities have been estimated as high as 150-500 ha -1 on subantarctic islands lacking other terrestrial mammals (Parker et al 2016;McClelland et al 2018), in fluctuating populations in arid Peru (Arana et al 2006), and during outbreaks on grassy California hillsides (Pearson 1963). Mouse plagues in Australian wheat-growing areas can exceed 2000 ha -1 (Singleton et al 2007). Hence, the maximum mouse densities we recorded at Maungatautari (up to 46 ha -1 in Q block and 23 ha -1 in M block) were high when compared with most New Zealand forest ecosystems, but not with other ecosystems globally.…”

“…Innes et al 1995;Witmer et al 2007;Ruscoe et al 2011), food supply or other factors (Pech et al 1999;Singleton et al 2007) may become limiting as mouse density increases following mesopredator and competitive release. This effect has been demonstrated in grassland/shrubland habitat, where lack of mouse population growth after experimental removal of higher- order mammalian predators was attributed to food limitation in locations with scarce grass seed (Norbury et al 2013).…”

“…Mice also become numerous when food is plentiful (King 1983;Wilson & Lee 2010). Extensive mouse plagues in the wheat-growing areas of south-eastern Australia follow rainfall and other possible prerequisites, such as reduced rates of predation and disease (Pech et al 1999;Krebs et al 2004;Singleton et al 2007).…”