Why reports of the duiker’s demise were greatly exaggerated

The Blue Duiker was predicted to face intense pressure from hunting, but these fears were unfounded. Bart Jekel.

In the mid-1990s, things looked grim for the blue duiker, a species of small antelope found predominantly in the forests of sub-Saharan Africa.

The blue duiker had long been hunted, primarily for its meat, but several scientific papers deemed the kill-rate to be unsustainable and warned of extinction.

But two decades on, numbers of the blue duiker have, in most regions, remained resilient.

“There have been many of these ‘death foretold’ scenarios, which just haven’t proved accurate as time has passed,” John Fa, a senior research associate with the Center for International Forestry Research (CIFOR), said.

So where did these dire predictions go wrong?

BOUNCING BACK

According to new research by Fa and fellow CIFOR senior associate Nathalie Van Vliet, the inaccuracies arose from a reliance on rigid biological indices that overlooked the variability of natural systems and local hunting practices.

For example, those 1990s estimates of how many duikers could be killed sustainably were based on inexact estimates of hunting “off-takes”, prey stocks and rates of reproduction.

Although this model created simple algorithms to more easily determine whether rates of killing were sustainable, there is now widespread agreement that it was beset with estimation errors.

“We need a softer approach — or what we’re calling a ‘resilience approach’ — to provide more qualitative analysis of the sustainability of bushmeat hunting,” Fa said.

“We see this as more effective than coming in with a clipboard and numbers and simply measuring biological indices that are very data heavy.”

NATURE AND NURTURE

The new research suggests that a broader range of factors — particularly social factors — should be evaluated to determine the health of the ecosystem and coordinate conservation efforts. That is, bushmeat-hunting systems in tropical areas should be regarded as “social-ecological systems”.

The resilience approach accordingly considers a much broader number of drivers, many of which were previously overlooked.

These can include local sources of income and food, infrastructure investments and rates of urbanization, operating at various scales. Even human conflict in countries such as the Democratic Republic of Congo and the Central African Republic will have an impact on off-take and resilience.

“Human action is integral to nature and so any distinction between social and natural systems is superficial,” Fa said.

The resilience approach emphasizes other variables too, notably space and time, such as whether a prey population lives in a valley or on a mountainside, or if it is the dry or wet season.

Given the wide range of variables that can influence sustainability, sophisticated “multi-agent” models are required, the authors argue.

BIGGER PICTURE

In practice, however, and assessments need to go even further, Fa argues: he believes that more stakeholder groups should be involved in the conservation methods prescribed by the resilience approach, particularly local communities.

Indeed, the resilience approach holds that, to be successful, a conservation strategy must have more aims than conservation alone.

This view represents another step in the gradual shift toward a more holistic understanding of land usage, whose many names include the “landscapes approach”.

A more holistic or integrated view understands the hunting system as one of many competing demands in an area — be they social, economic or environmental.

In the case of bushmeat, the demand cannot be overlooked. Bushmeat is a crucial source of food in Central Africa, one of poorest regiions in the world, where 104 million people survive on an average yearly income of US$583.

“Obviously the needs of these people have to be represented and blanket bans on hunting are likely to be ineffective, especially when they are unnecessary,” Fa said.

“When you devise a conservation strategy you need to engage local people, and make sure that they understand the point of the conservation efforts.

“If they don’t get the point, then it won’t work.”

‘Landscape approach’ defies simple definition -

and that's a good thing

In the case of duiker hunting in Central Africa, the ecological and social demands are plainly symbiotic: for future generations of local hunters to continue hunting duikers, the species must survive, and for this to happen they must be hunted sustainably.

While numbers of the blue duiker have remained resilient despite the doomsday predictions of the 1990s, many species remain critically endangered in the region.

Although Fa and van Vliet’s research has undercut the methodology behind some extinction predictions, they are keen to stress that it does not follow that extinction warnings are universally false.

“There are still many legitimate extinction concerns. But that’s not the issue that we are addressing here,” Fa said.

“The point we are making is that in conservation it’s not good to be constantly crying wolf.”