Since 1964, 46 years ago, the Otira Valley on the western side of the Arthur's Pass Highway 73 has been regularly treated with 1080 to control possums. The treatment, a combination of foot and aerial operations, occurs roughly every 3 years when possum numbers increase to a threshhold level where they cause damage to the native vegetation.
Today, February 2, a field day is being held by DOC and nature lovers to celebrate perhaps the most stunning display of southern rata in flower that we have ever seen in the valley. Whole hill sides are covered in the crimson blaze that has moved as a wave up the Otira hill sides.
The upper Arahura Valley, a mere 15 km south as the crow flies, has never had integrated possum control and here the hillsides are a dull green punctuated by the bleached white sticks of dead rata trees. Dead rata can be seen over many of the hill sides away from the Otira 1080 treatment area. The trees simply cannot withstand the constant nibbling by possums and eventually die everywhere that there is no possum control.
The Otira Valley is not only a refuge for healthy rata forest. It is also the centre of a vigorous population of weka and great spotted kiwi. These birds are thriving here. So healthy is the weka population that they are now spreading south into Arthur's Pass summit and the township of Arthur's Pass. Clearly the weka here, just as are the weka found in the Upper Copland Valley of Westland National Park (another rata haven), are benefitting from the successful pest control through DOC's 1080 work.
Anyone driving through Arthur's Pass today or tomorrow is welcome to stop where the vehicles are gathered and the display posters are up and talk to conservation staff and volunteers who will point out the results of the Otira native forest and bird protection programme...and of course photograph whole hill sides awash with scarlet flowering forest!
