Heather beetle released into Tongariro National Park

Ruapehu Bulletin, Volume 13, Issue 623, 13 February 1996, Page 14

Heather beetle released into Tongariro National Park

Weed control in Tongariro National Park entered a new phase last week with the release of a beetle that will eat the most serious weed in the park, exotic heather Calluna vulgaris. Two hundred and fifty adult beetles of the species Lochmaea suturalis were released from small holding cages into heather bushes at two sites in the park, chosen because they are both dominated by heather and represent different climatic conditions which increases the chance for the beetle to become established. The two sites, one on the western side of the Park and one on the eastern side will also allow for close moritoring of the beetle' s survival and effects. Before the beetle could be released, conservation minister Denis Marshall had to approve its introduction into the park, and the Ministry of Agriculture had to approve its release from quarantine. This follows support from the New Zealand Conservation Authority, the Tongariro/ Taupo Conservation Board, the Forest and Bird Society and many other agencies and individuals. "I'd like to personally acknowledge the support and commitment to this project by a large number of people" said Mr Marshall. "Opposition against the original planting of heather in Tongariro National Park was

one of the earliest environmental issues in the country and was debated in Parliament in 1927. It's good to see the continuing enthusiasm for protection of the park." Dr Harry Keys, advisory scientist for the Tongariro/Taupo Conservancy of the Department of Conservation, said the release is a milestone in the history of weed control in Tongariro National Park. Any effect of the beetle is not likely to be seen for several years. The beetle is being introduced to control calluna (or ling) heather which is the most widespread and invasive weed in the national park and it is still spreading within, and far beyond, the park. "It has caused major reductions in the biomass of indigenous plants, reduced insect diversity and interfered with natural processes of plant regeneration and succession in tussock and shrub-lands. There is a potential for local extinction of some insect species and rare plants in the area," said Dr Keys. More than 10 years of research, workshops, consultation and publicly reviewed environmental and importation impact assessments have indicated that biological control was the only viable and practical control option for the heather problem as a whole. Extensive scientific testing confirmed that calluna heather is the sole host of the beetle. This means that there is negligible risk of damage

or direct impacts to native or other non-target plants. As heather is not a specific host of any native insect or animal they will not be threatened by its control. The heather beetle is not poisonous, does not bite people or animals and does not have an offensive odour. The beetle and its larva browse on heather foliage. The intent of the beetle release is that browsing will reduce heather's competitive advantage and that of new generations of heather. This would allow natural succession of indigenous plant species to suppress the heather and reduce its rate of spread into adjoining areas, both within the national park and in neighbouring properties.