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Wednesday, 8 May, 2002, 12:08 GMT 13:08 UK
Economists model animal survival
Elephant, BBC
Species must pay their way or risk extinction
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By Kim Griggs
in Wellington, New Zealand
A new economic model could improve our understanding of how to help endangered species.

It is only by discovering what motivates human behaviour that we can discover ways to change it

Dr Robert Alexander
The model, developed by New Zealand-based resource economist Dr Robert Alexander and postgraduate researcher Chris Fleming, helps determine how much money particular species cost or benefit humans.

The two men believe their work gives a clearer insight into the socio-economic pressures that push animals to the brink of extinction.

The Massey University researchers say the model could be used to establish whether conservation programmes have any realistic chance of success.

Human behaviour

Understanding the economics of protecting species is crucial, Dr Alexander says, because "the simple and perhaps unpleasant truth" is that species must pay their way or risk extinction.

"People say what causes extinction - and ecologists say it as well - is loss of habitat, excessive hunting, exotic species being introduced, etc.

"And that's all true. But that's a direct cause. What's underneath that, what makes those things happen? The fundamental causes are economic and social.

"It is only by discovering what motivates human behaviour that we can discover ways to change it."

The researchers have built a model that takes these factors into account.

Declining populations

"We believe that people will behave in accordance to what this model says," Dr Alexander told BBC News Online.

Rhino, BBC
The model inputs multiple species
"If the model suggests that the optimal population [of elephants, for example] is significantly lower than the current population, we believe that people will then behave in such a way that they will basically cause the elephants to decline in population."

While the idea of figuring out how much it costs to allow animals to live on the land they occupy is not new, other models have tended to concentrate only single species.

Those models suggest an optimal population much lower than currently exists, a result Dr Alexander first noticed in studies about the elephant.

Predator and prey

"The elephant effectively is being charged with the entire land which it needs, alone, even though that same land is occupied by lions, and rhinos and leopards and all sorts of other valuable species."

The new model developed by the Massey economists allows for multiple species to be included and also the relationships between species, such as that between predator and prey.

"What makes this different is it's the first model - at least as far as we know - that includes multiple species and the land component," says Dr Alexander.

In a paper they have written, the economists illustrate their work using the examples of a single species elephant model, a single species rhino model and a two-species elephant and rhino model.

Community involvement

"The single species elephant model shows elephants declining to extinction, but when rhino are added, they maintain a positive population level," says Dr Alexander.

Wild dog, Dr Robert Alexander
The model will be used on a wild dog programme
Image courtesy of Dr Robert Alexander

"Rhino continue to survive in both models, but the variation in populations is reduced after elephants are added."

Dr Alexander says these outcomes match the real world much more closely.

As an example, Dr Alexander points to The Campfire Project in Zimbabwe, which gives local communities rights over animals such as elephants.

Incentives are better

"Elephants knock down buildings. They are dangerous to your children. They eat your crops. They're a big pest if you are an indigenous person living where elephants live.

"So, if some poacher comes along and wants to shoot the elephant, what incentive do you have to notify the authorities, or try to stop them?"

"But if that's your kids' school, textbooks for your kids' education - if that's worth a couple of hundred Zimbabwean dollars to your household, then you care," Dr Alexander says.

Economic incentives rather than legislation are a more compelling way to change human behaviour, he argues.

Wild dog

"There are a lot of species all over the world that are endangered, that are technically owned by the state, and that are illegal to hunt. But who is there to prevent it?"

Dr Alexander is about to use the model in a South African programme to try and restore the populations of the African wild dog on private land.

The wild dog, now endangered, has been culled for years for killing farmers' stock.

The model will help determine if the value from potential tourism can outweigh the cost of stock killed by the dogs.

See also:

08 May 01 | Sci/Tech
World wildlife warning
24 Aug 01 | Sci/Tech
Dying species 'endangering' Earth
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