Whether it’s being used to keep wild animals safe from us, or us safe from them, scientists from the Zoological Society of London (ZSL) and the Wildlife Conservation Society (WCS) are urging conservationists to use fencing as a last resort.
The debate about fencing has divided wildlife officials, conservation organizations and scientists, with supporters arguing that it’s necessary to reduce wildlife conflicts with humans, protect endangered species and keep livestock safe from predation or the spread of diseases.
In March 2013, lion biologist Craig Packer of the University of Minnesota fueled the debate when he and 57 co-authors published a study in the journal Ecology Letters arguing in favor of fencing as a tool to help save Africa’s lions after studying lion densities at 42 reserves.
They argued that lions had already lost 75 percent of their habitat and that the population of humans in Africa would only continue to grow leading to further loss, while they predicted that nearly half the unfenced lion populations may decline to near extinction over the next 20–40 years.
The study was later countered by other scientists, who believe fencing can do more harm than good. Opponents raised concerns about how fencing can alter habitats and migration routes, along with raising serious questions about how we decide which species is the most important to save. They also raised concerns about the subsequent problems that come with trying to manage landscapes to benefit a single species.
After weighing the pros and cons of large-scale fencing, scientists from the ZSL and WCS are weighing in and arguing in a new paper published in the journal Science that it should only be used as a last resort.
“In some parts of the world, fencing is part of the culture of wildlife conservation – it’s assumed that all wildlife areas have to be fenced. But fencing profoundly alters ecosystems, and can cause some species to disappear. We’re asking that conservationists as well as other sectoral interests carefully weigh up the biodiversity costs and benefits of new and existing fences,” said ZSL’s Rosie Woodroffe, lead author of the study, in a statement.
While they agree that fencing can have benefits and has helped some wild animals, they believe that segregating wildlife can drastically impact the landscape and make some species more vulnerable to extinction by isolating populations. In some cases fence wire has also ironically become a tool for poachers who steal it and use it to make snares.
Unfortunately, the loss of top predators can be particularly harmful as the impact trickles down through the ecosystem. When it comes to large migratory animals, they don’t just need access to vast areas to support their populations, they need to be able to move freely. Fencing has already been blamed for the drastic decline in wildebeest populations by blocking their migration routes between wet and dry areas.
Along with concerns about habitat fragmentation, the scientists also raised concerns about the need for wildlife to be able to relocate on their own as climate change impacts their environments and access to food and water. They believe fence removal in some places may be necessary in the future.
They also hope that with other measures that will benefit both humans and animals, priorities will be placed on keeping open spaces as connected as possible before anyone decides to turn to fencing.
“A variety of alternative approaches – including better animal husbandry, community-based crop-guarding, insurance schemes, and wildlife-sensitive land-use planning – can be used to mitigate conﬂicts between people and wildlife without the need for fencing. WCS projects working with local people and government agencies have shown that human–elephant conflict can be dramatically reduced without using fences in countries as different as Indonesia and Tanzania,” said co-author Simon Hedges of WCS.
One thing everyone seems to agree on is that whatever is done, it’s going to be expensive.
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