By Kim Griggs
in Wellington, New Zealand
May 8, 2002
Species must pay their way or risk extinction
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
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
"We believe that people will behave in accordance to what
this model says," Dr Alexander told BBC News Online.
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
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
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.
"The single species elephant model shows elephants declining
to extinction, but when rhino are added, they maintain a positive
population level," says Dr 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
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
"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.
"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
The wild dog, now endangered, has been culled for years for killing
The model will help determine if the value from potential tourism
can outweigh the cost of stock killed by the dogs.