The Influence of Ship Rats (Rattus Rattus) on the Habitat Preferences of the House Mouse (Mus Musculus)

• Main Author: Hancock, Benjamin
• Other Authors: Linklater, Wayne, Moles, Angela
• Format: Master Thesis
• Language: English
• Published: Victoria University of Wellington 2008
• Subjects: Rat; Mouse; Ecology; Rattus rattus
• Online Access: http://researcharchive.vuw.ac.nz/handle/10063/863

As methods and successes of Rattus rattus (ship rat) control progress, particularly in island environments, the importance of managing Mus musculus (house mouse) increases. M. musculus can negatively impact on a variety of native fauna and flora, potentially creating long term cascading effects. M. musculus populations benefit with the reduction in R. rattus abundance and recover sooner from pest control programs. This three-part study investigated the habitat utilisation of M. musculus and how their relationship with R. rattus influences their habitat preferences. Firstly, hypotheses about the habitat preferences of M. musculus were tested over a landscape scale to determine the features of the environment most important to their distribution. Then the direct effect of R. rattus presence on M. musculus habitat-use was investigated in arena trials. Lastly, in the same arenas, canopy cover was tested as an indirect cue for M. musculus to evaluate the presence of R. rattus. Across 32 sites, M. musculus were the most abundant in warm dry habitats. North facing slopes and rank grass cover were the features of the environment that had the strongest relationship with abundance. In arenas M. musculus foraging activity was 52% lower in patches of short grass when R. rattus scent was present but foraging in rank grass and bare ground was not altered, suggesting activity was suppressed not competitive displacement. There were no significant changes in M. musculus foraging behaviour between different canopy treatments. Although a trend of nocturnal foraging activity dropping 26% when high canopy cover was over short grass compared to short grass patches with lower or no canopy treatments may indicate a risky habitat. M. musculus use of dense ground cover was common theme in this study and in the literature. R. rattus do influence the habitat selection of M. musculus though this was with direct presence more than indirect cues.