Otira Pest Control Programme
Otira is a fantastic place to see rata when it is in bloom. It's also an area where possum control has been done since the 1960s. Otira has become a showcase for the southern rata/kamahi forests that have been, and are being, badly damaged by possums in the rest of Westland.
All of the area that is pest controlled falls within Arthur's Pass National Park.
What are we protecting?
The Otira Pest Control Programme is primarily undertaken to protect the health of the forest. The Otira Forest is of high significance for conservation, it includes a range vegetation dominated by southern rata and kamahi but including the podocarps such as rimu in the mid altitudes, montane totara above 500m, the native cedar (kaikawaka) in the very cold spots, the fuchsia in the slips and stream sides, and the broadleaf often seen growing as an epiphyte in other trees as it tries to avoid its arch enemy, the deer.
The Otira area also holds populations of whio, kiwi and kaka; large birds that are becoming uncommon elsewhere. The full ranges of common forest birds are present throughout the area. Protection of forest habitat for these animals is vital to their long term survival.
What are the threats?
Increases in possum densities in the Otira Valley threaten vulnerable species to various degrees. Possums operate on a "eat the good stuff first" basis. They target the species they most like to eat first, then move on when the ready supply has been exhausted. This is why different species of trees are affected differently.
Rata, kamahi fushcia and wineberry have disapeared from many places due to being browsed by possums.
Why use 1080 pest control?
Due to mountainous terrain and the size of the area requiring treatment, aerial 1080 is considered the most practicable method of possum control for this area.
Regular monitoring of tagged trees in the Otira Forest shows that the most vulnerable species in these forests; fuchsia and wineberry, are being maintained in good condition with very few browsed by possums. Possum numbers need to be kept low to sustain healthy populations of these species.