Pest-exclusion fence
A pest-exclusion fence is built to exclude certain types of animal pests from an enclosure. This may be to protect plants in horticulture, to preserve grassland for grazing animals, or to protect endemic species in nature reserves.
Design techniques
Animals can be excluded by a fence's height, depth under the ground and mesh size. It is also important to choose a construction material that cannot be climbed; furthermore, sometimes it is necessary to create a subsurface fencing element to prevent burrowing under the fence.[1][2]
Examples
- The 1.9m-high fence at the Orokonui Ecosanctuary in Waitati, New Zealand is designed to keep out all introduced mammals such as possums, rats, stoats, ferrets and even mice. It uses stainless steel mesh that continues down to form a skirt at ground level that prevents animals from burrowing under it. On the top is a curved steel hood that prevents climbers like cats and possums from climbing over the top.[3]
Use in New Zealand
Prior to human settlement New Zealand had no land-based mammals apart from three bat species. The introduced mammal species have since caused huge ecological changes to the biota of New Zealand. Pest-exclusion fences are increasingly used for conservation of indigenous species by excluding all mammals.
Locations of predator-proof fences include:
- Cape Brett
- Deans Bush, Christchurch
- Karori Wildlife Sanctuary
- Maungatautari Restoration Project
- Orokonui Ecosanctuary
- Shakespear Regional Park
- Styx Mill Reserve, Christchurch, New Zealand (under construction)
- Stewart Island, New Zealand
- Tawharanui Peninsula