East Harbour Regional Park Article September 2021

Deer, although a beautiful animals, need a large amount of plant matter to survive. They disproportionately browse on desirable species such as kamahi, mahoe, broadleaf and Coprosma species, and sustained browsing by deer and goats can ultimately change forest composition through the removal of these species. They have already wiped out native species such as Kirks Tree Daisy and Raukawa.

There are negative knock-on effects.  Clearing out forest undergrowth opens it up to the elements, which in turn causes loss of soil nutrients and undermines water retention. Loss of these species also reduces fruits that support native birds and insects that would otherwise inhabit a leafy forest floor, leading to a decline in both plant and animal biodiversity. Due to historic high numbers of deer there are already very few preferred broadleaf species throughout much of the forest. Even low numbers of deer can inhibit the growth and recovery of those that remain.

A strategy to maintain low numbers of deer in the park to support a healthier forest over recent years has led to the current approach of two professional hunting blocks (spring and autumn) with a little help from a recreational hunting ballot (late summer/the roar).

We need to better understand the spread and population size of deer in the park. We did consider helicopter thermal imaging but after consultation with deer control professionals Greater Wellington Regional Council and Hutt City Council are currently planning to undertake faecal DNA sampling. This involves a grid survey of the park for deer scat that will be sent for DNA analysis. I am hoping this will be followed by a shorter deer cull if funding permits. Once we have the baseline data this should give us a much better picture of deer in the park, how many individuals there are and their home ranges. We can then re-establish a new set of targets to keep deer to low densities throughout the park and use the information to inform our ongoing culling methodology.