The den use of possums (Trichosurus vulpecula) may be density dependent, meaning that individuals change their denning behaviour in response to changes in population density. Increases in den use due to changes in density may result in increases in bovine tuberculosis (Mycobacterium bovis; bTB) transmission among possums, as infection has previously been correlated with den use. In this study, the den use of a possum population was monitored in 2011 before and after a density reduction event. Females increased their den use following density reduction, but males did not.
The introduced brushtail possum (Trichosurus vulpecula) is the most important wildlife host of bovine tuberculosis in New Zealand and is considered to be a major environmental and agricultural pest. Dry grassland ecosystems in New Zealand include some of the least protected and most threatened native biota. Drylands cover 19% of the country, but there is little published information on the population density of invasive brushtail possums in these environments, and previous estimates are not based on quantitative methods.