A contractor sets a self-setting trap to trap possums, rats and stoats in the Dunedin Botanic Garden.
Animal pest control
The Botanic Garden is controlling the animal pests possums, rats and stoats which destroy the garden’s bushes and plants. There are about 50 traps throughout the garden which are baited and mounted to be safe for domestic pets. They’re not in high use areas and their effectiveness is being monitored.
The trapping is being carried out with the support of City Sanctuary, a DCC project that implements community-led predator control in backyards and reserves. It is part of Predator Free Dunedin, the conservation collective aiming to get rid of possums, rats and stoats from Dunedin by 2050.
City Sanctuary is establishing a network of traps in Dunedin reserves and parks that can support species vulnerable to predation, such as riflemen and South Island robins. Now the Botanic Garden joins the trapping taking place in Ross Creek, Woodhaugh, Dalmore Reserve, Chingford Park, Signal Hill and the town belt. The garden’s traps are looked after by City Sanctuary volunteers.
Since 2007, animal pests have been controlled in the garden by shooting. An average of 25 possums a year have been killed, mainly in the rhododendron dell. It is hoping the trapping will boost these pest numbers.
Pest plant control
The introduction of trapping coincides with the garden’s intensified efforts to blitz pest plants such as sycamore, elderberry, blackberry and old man’s beard.
Pest plant control at the garden has been carried out over the past 20 years, with the help of Taskforce Green workers and volunteers. They removed carpets of ivy from the bush in the garden 15 years ago which has cleared the understorey to allow native ferns to thrive. Volunteers also hold weeding days, attacking aluminium weed and hypericum.
The extent of the garden’s pest plant problem was highlighted in a 2015 – 2016 study. This led to a more targeted approach from 2017 when gardening staff began spending one or two days a week during the winter controlling the most troublesome weeds.
Sycamore is one of the aggressive weeds they are targeting. Seedlings are pulled out as they pop up, and large trees are sprayed or ring-barked.