A new study is helping shed light on the country's urban possum population - with researchers hoping the data will help conservation efforts to control the invasive pests.
Researchers tracked possum populations at three sites in Dunedin to get a sense of how tightly packed possums might be in an urban setting.
Charlotte Patterson, a researcher at the University of Otago and the study's lead author, says with the country's ambitious goal of being predator-free by 2050, it's vital we learn more about possum populations all over the country.
"There's been lots of studies of possum density in other environments because it tends to be quite an important thing to measure and it influences other parts of population dynamics, but there's been no studies done in the urban environment in New Zealand," Patterson told Newshub.
She says researchers found one forest area in the city, Jubilee Park, had a density of around three possums per hectare. And while this is low compared to more rural areas - where there can be as many as 20 possums per hectare - it's enough to cause harm to native wildlife.
Patterson says possums are "very bad for the forest".
"They feed on many native species and they can do so to the point where they actually cause specific trees to die off. They're also quite harmful as predators of chicks, adult birds, invertebrates, lizards potentially, and they also compete with birds for food resources."
Although other parts of the urban area had relatively low densities, the study confirmed cities are an important habitat for possums, which those working to control the pests will need to take into consideration in the future, Patterson says.
"This shows that the possum density can change a lot just in a small space just in the urban environment, which probably reflects the availability of resources like forest and food resources.
"This is important because we're becoming more interested in conservation in the urban environment. Predator Free 2050 and things like that are making us more engaged in trapping in those urban areas so we need to understand some of the fundamental biology of possums in urban areas in order to actually make decisions about trapping in the future."
Patterson says she hopes the study can highlight the capacity of urban areas to have "quite substantial possum populations" and to "provide some really robust data for information on future studies of possums in these areas".
