Pest-exclusion fence

A pest-exclusion fence is a barrier that is built to exclude certain types of animal pests from an enclosure. This may be to protect plants in horticulture, preserve grassland for grazing animals, separate species carrying diseases (vector species) from livestock, prevent troublesome species entering roadways, or to protect endemic species in nature reserves. These fences are not necessarily traditional wire barriers, but may also include barriers of sound, or smell.

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. Fences are usually designed with the target pest species (the species to be excluded) in mind, and the fences are made to effectively exclude those species. This results in a wide variety of designs for pest exclusion fences (see examples below). Often the fence is encircled in electric wire to ensure that animals can not climb over the fence.

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.