A Landcare Report in 1995 showed the extent of damage being caused by possums on vegetation in East Harbour Regional Park. Foliar browse was found to be particularly heavy on a range of broadleaf trees and especially on the northern rata. MIRO volunteers started trapping possums around Hawtrey in the rata forest, while Hutt City Council provided householders adjacent to the bush with Timms traps to catch possums on the urban fringes. This became known as the Possum Busters campaign. It continued for a number of years but gradually wound down. MIRO however continued to trap within the Park, moving traps as areas were cleared.
In 2004 when GWRC took over as Park managers, they proposed the set-up of a park-wide network of possum traps and agreed to fund it if MIRO would provide volunteers to service the traps. The network which now extends right across the 2000ha of the northern forest block comprises over 60km of trap-lines and currently there are 477 possum kill traps and rat bait stations. The network continues to be added to as required.
After possums the next predator to be targeted was rats. Attempting to control rats across the Park was not feasible - rather a Mainland Island of approximately 350ha centred on Butterfly Creek catchment was selected (approximately the same size as Karori Sanctuary). GWRC has taken up this task and has set up a grid of rat bait stations 150m by 100m inside the Mainland Island. Contractors are used to apply bait for several months during the breeding season for birds.
A Nursery to assist restoration of the Parangarahu Lakes Area:
In 2004 the lakes block (now known as the Parangarahu Lakes Area) was returned to the Park after the cessation of a grazing lease to a local farmer. The area was to be allowed to regenerate naturally but to speed up the process MIRO proposed the establishment of a nursery to grow eco-sourced trees to attract birds and facilitate the spread of native seed into areas of gorse.
GWRC commissioned a plan to guide the restoration. This plan by Geoff Park identified the tree species required and also identified suitable plots for selective planting in the area.
The MIRO nursery was established in 2005 and the first 800 trees from there were planted in the winter of 2007 in a specially fenced plot near Lake Kohangapiripiri to protect the small trees from hares. In the winter of 2008 the first plot was in-filled to account for losses in the harsh environment and a second plot was started.
MIRO award November 2008
The GWRC Rata Community Partnership Award was presented to MIRO at a ceremony in November 2008.
The award recognises the hundreds of hours the sixty members of MIRO have put into almost eradicating possums from the MIRO area. Over a period of four years, volunteers have brought possum rates down from 27 caught per 100 traps set to 1.8 per 100 traps, which has led to the regeneration of native bush and a growth in the numbers of birds.
At a meeting on 5 June 2009 the members present voted unanimously to apply to the Registrar of Incorporated Societies for incorporation under the Incorporated Societies Act, and to apply to the Charities Commission for charitable status.
By 30 July 2009, MIRO had been incorporared and had been registered as a charitable entity under the Charities Act 2005.