Fencing for Conservation: Restriction of Evolutionary Potential or a Riposte to Threatening Processes?

The conflict between increasing human population and biodiversity conservation is one of the IUCN’s key threatening processes. Conservation planning has received a great deal of coverage and research as a way of conserving biodiversity yet, while theoretically successful, it has never been tested. Simple lines on maps to illustrate conservation areas are unlikely to be successful in the light of human encroachment. It may be that some form of overt display is necessary to ensure the protection of reserves. This may be signage, presence of guards/rangers or physical fencing structures. The need for some form of barrier goes beyond restricting human access. The megafauna of Africa pose a genuine threat to human survival. In southern Africa, fences keep animals in and protect the abutting human population. Elsewhere, fencing is not considered important or viable. Where poverty is rife, it won’t take much to tip the balance from beneficial conservation areas to troublesome repositories of crop-raiders, diseases and killers. Conversely, in New Zealand fences are used to keep animals out. Introduced species have decimated New Zealand’s endemic birds, reptiles and invertebrates, and several sites have been entirely encapsulated in mouse-proof fencing to ensure their protection. Australia faces the same problems as New Zealand, however surrounds its national parks with cattle fences. Foxes and cats are free to enter and leave at will, resulting in rapid recolonisation following poisoning campaigns. How long will these poison campaigns work before tolerance, aversion or resistance evolves in the introduced predator populations?

How can we best protect the world’s biodiversity in the face of the growing human population? This question is the central theme of contemporary conservation biology. The protection of biodiversity from overuse by fencing it off from the surrounding landscape is one of the conservation tools available to us. Fences have become common features of our environment and firmly entrenched in our lives, as we use them to surround our farms, houses, and anything we want to keep to ourselves or protect. Within the last few hundred years, conservationists have started using fences to protect biodiversity from overuse and poaching, as well as to protect people from wild animals, especially large carnivores and megaherbivores such as elephants and rhinos. The methodologies for, and approaches to, the use of fences by conservationists vary, and range from the intensive fencing practices in places such as South Africa, to the complete avoidance of fences in other places such as parts of East Africa. In other areas such as Australia and New Zealand fences are used, at enormous costs, not to protect biodiversity from people, but to protect vulnerable native species from invasive alien species such as foxes and cats. Some may argue that biodiversity conservation is not possible without fences, while others argue that the fencing in of biodiversity simply creates zoos and restricts evolutionary potential.

Fencing for Conservation: Restriction of Evolutionary Potential or a Riposte to Threatening Processes? reviews some of the issues regarding fencing for conservation and summarises the current state of knowledge and practice, describing numerous case studies from around the world. As such it will be of interest to students and researchers of conservation biology, invasion biology, ecology and wildlife management.