Wainuiomata-Puketaha and the end of extinction

The Wainuiomata-Puketaha eco-sanctuary project and its role in ending the prospect of extinction for NZ’s unique forest species

Wainuiomata-Puketaha and ‘the end of extinction’.

The Wainuiomata-Puketahā eco-sanctuary is Jim’s latest conservation project. It is an example of the large-scale eco-sanctuary which was proposed by Jim in 2010 and advocated by Sir Paul Callaghan in his last address at Victoria University (2012).

Wainuiomata-Puketahā has the potential to revolutionise conservation management in New Zealand by providing an example of the giant pest-exclusion fenced eco-sanctuary and demonstrating that the most endangered species, currently largely restricted to off-shore islands, can be permanently returned to the mainland, and have their populations boosted to the extent that they are no longer threatened with extinction. In addition, it will demonstrate that the ‘nursery and halo’ model resulting from giant fenced sanctuaries can increase the diversity and abundance of many species across large areas and bring substantial tracts of our primordial forests back to life.

**Puketaha from the east ridge**. Photo JR Lynch

The problem

Many of NZ’s iconic forest species (e.g., kakapo, hihi, little spotted kiwi, SI and NI saddleback, red-crowned kakariki, Cook Strait Tuatara) are still highly endangered and are largely restricted to one or two major populations on offshore islands. Others are still on the mainland but are at risk of extinction as they are in low numbers with small or fragmented populations (e.g., kokako, orange-fronted kakariki, robin, rowi kiwi, mohua, rifleman, kaka, pateke). Many species still depend on pest-free offshore islands for their survival, and we have run out of suitable islands with quality habitat. Islands are hard for people to access, and few birds can migrate from them to extend their range. A disease outbreak, pest invasion or climate catastrophe could wipe these fragile population out. Existing pest management techniques are not up to the task of clearing large areas of the mainland of pests and keeping them clear for long periods of time and no technological breakthroughs are in sight. See Jim’s recent TEDx talk on the subject for a full summary of the issue and the solution.

The Solution

We need further ‘insurance’ against extinction of these species. The solution is the pest-exclusion fence, conceived by Jim in 1992, developed at Zealandia and proven over the last twenty years by the 12 larger fenced community and private eco-sanctuaries.

Jim’s vision is to have a network of very large fenced eco-sanctuaries (3,000 plus ha), located adjacent to large (50,000 ha plus) areas of intensively managed forested ‘halo’ zones to maximise the ‘nursery and halo’ effect. These giant sanctuaries would become biodiversity hubs for their localities, and as a bonus, like Zealandia and other sanctuaries, they could become social and economic hubs as well. By starting with six large sanctuaries, up to 20,000 ha of pest free habitat could be created (twice the size of the existing pest-free offshore islands) with ‘halo’ zones approaching a quarter of a million ha in total. This would secure all forest species against extinction and greatly expand the range and abundance of almost all forest fauna species.

Wainuiomata- Puketahā

The Wainuiomata Water Collection Area, known by Māori as Puketahā (hill of calabashes) is a 3,350-ha valley network which has been part of wellingtons water supply for over 140 years. It is unlogged, primordial, lowland, rata-rimu dominant rain forest with many 1,000-plus year-old trees. It is large enough to hold genetically viable populations of every forest fauna species representative of the Wellington area.

The proposal is to pest-exclusion fence (29.9 km) the whole catchment, restore all missing and extant species to the area and maintain it as a biodiversity, social and economic hub. Wainuiomata is ideal habitat for kakapo, hihi and rowi kiwi and could double the existing populations of each. It could increase the populations of ten other threatened species by as much as one third and extend the range and abundance of many others. It is adjacent to 40,000 ha of quality forest in the Remutaka range and could revitalise the whole area, biologically, socially, and economically.

Jim envisages Wainuiomata-Puketahā as the pilot project for a network of giant sanctuaries that would end the prospect of extinction for our endangered forest fauna.

Background

Jim’s conservation work in Wellington City over the last 30 years (see conservation section and Zealandia book section) and the resulting community eco-sanctuary movement that sprung up behind it (see Innes et al 2019), has proven that pest-exclusion fencing can keep substantial areas, (up to 3,000-ha) essentially pest-free for long periods of time and enable the return of highly sensitive endangered species to the mainland. Other research has proven that fenced eco-sanctuaries have a significant effect in building species populations in surrounding areas (the ‘halo’ effect) and creating biodiversity, social and economic value.

Jim and Eve first encountered the Wainuiomata Water Catchment in 1995 when they were collecting rata seedlings for the Forest and Bird home nursery. Jim always thought this special forest had the potential to be a giant sanctuary but thought it too large to fence and was concentrating on getting Zealandia established. Instead, he lobbied GWRC to manage the area for biodiversity. Part of the catchment was deer fenced and a mainland island style pest management programme was instituted for 1,200 ha of the western section of the catchment. The whole catchment became a Key Native Ecosystem (KNE) managed area.

The Proposal

In December 2001 Jim and Eve were visiting the catchment and discussing the area with the GWRC Ranger (Ricky Clarkson) and GW staff. They advised that the pest control was having limited success and sought Jim’s advice as to whether the area could be fenced. An interim assessment indicated that it may be ideal for fencing. Ricky provided a provisional fenceline and Jim’s enquiries to the Kakapo Recovery team regarding its potential as kakapo habitat were encouraging. In June 2022 Jim wrote and presented the proposal (see The Wainuiomata Project. JR Lynch 2020) to the landowners the Greater Wellington Regional Council (GWRC) and local iwi (Taranaki Whānui). DOC were also introduced to the project. It was agreed that a feasibility study would be funded to test the idea.

The Feasibility Study

Jim was contracted to lead the study which began in March 2021 and was completed on time and under budget in November 2022. See ‘Puketahā. Wainuiomata Eco-sanctuary Feasibility Study. JR Lynch 2022). The study concluded that the project was feasible and set out the development pathway, assessed the funds required and identified the risks. The study received a positive reception, and it was agreed by the three partners that it proceed to the funding stage. Funding is now being investigated.