The Snowdon Forest area is regarded as “mostly ecologically intact and supporting important habitats of indigenous fauna“. It was assessed by the ecological auditors, Wildland Consultants Ltd, as having “very high value for ecological context”.
There is one potential positive effect of the monorail project, which could be increased control of pests in the area. Otherwise some of the main impacts on the ecology could be:
- Permanent loss of 22 hectares (54 acres) of native forest habitat and 4.35 hectares (10.7 acres) of non-forest habitat
- Edge effects mean that damage could extend to 68 hectares of forest (168 acres)
- Clearance of around 19,555 trees, including around 76 very large red beech trees in significant lowland red beech forest.
- The effect of cutting two corridors through the bush, opening up a potential wind tunnel which could cause much more extensive damage to the bush and the habitats it supports.
- The risk of having to cut down large red beech trees which are a habitat for nationally endangered long-tailed bats and other fauna. Red beech trees can be hundreds of years old so they cannot be replaced.
- Invasion of weeds along the route.
- Permanent damage to tussock grasslands.
More information can be found in the ecological audit commissioned by DoC and in the terrestrial ecology report included in the monorail proposal. Riverstone’s assessment of environmental effects has a shorter section on the ecological effects.
DoC’s ecological audit found the following impacts:
“Potential adverse effects include:
• Considerable earthworks to construct monorail and access tracks – to be converted to a bike trail following construction.
• Clearance and edge effects of at least 68ha of wildlife rich forest, approximately 19,555 trees, including around 76 very large red beech trees in significant lowland red beech forest.
• Significant adverse effects on rare unmodified low altitude red tussock valley grasslands – about 4.5ha.
• Significant adverse effects on threatened species including the nationally endangered Long-tailed bat, threatened mohua, and kaka, and other forest birds. (Around 5,500 large trees would be cleared). As bats roost in clusters of trees, DOC says, if such a cluster were felled the effects on the bat population could be catastrophic.
• Impossible to accurately assess the impacts due to use of an envelope approach over a200m wide corridor rather than precise routes..
• Increased weeds and pests.
• Sedimentation pollution runoff, to effected small streams and rivers including the Mararoa and Kiwi Burn Rivers.
• Potentially significant landscape effects, described by the technical landscape audit as significantly compromising the outstanding natural values of the landscapes of the Snowdon Forest part of Te Wahipounamu South West New Zealand World Heritage Area..
• Loss of the popular family tramp to the Kiwiburn hut – (hut is to be relocated).”