Sunday, 19 February 2012

Threats and opportunities of the bushmeat trade

Snared giraffe, Serengeti NP Jan 2011. A major target right now
Following my post a while back about Dennis Rentsch's work on the bushmeat trade around Serengeti, Matt asked me to cover this issue in a bit more depth. (Though if you want to see how it's possible to have a sustainable harvest of around 100,000 wildebeest per year from Serengeti, with a net value of $2.5-$8.5 Million per year check the original post here!) And there've been a number of interesting papers recently that have started to fill in some details. It's not a subject I've much experience of, so I'm skimming the surface a bit, but I think it might at least highlight some of the issues involved.

We'll start with the caveats. Understanding the bushmeat trade is tricky - in most places it's illegal, and people aren't always going to talk freely. And if they do talk, there's a good chance they won't tell you the truth either - they might either say they do less hunting than they really do to play down the impact, or they might go down the macho route and tell you they're excellent hunters and never come back without a pile of buffalo, etc... Dennis's work took an alternative strategy, instead of asking the poachers to tell him what they hunted, asking the villagers to tell him how much bushmeat they consumed and working back to the harvest that way. Others have worked on data using poacher arrests, viewing this as an index of poaching activity - though there's no way to tell what proportion of poachers get away with it (what poacher, when arrested, will really tell you how often they've been poaching before and not been caught?!). The only comparison between these three methods is Dennis' and that suggests that measuring consumption gives a poaching pressure that parallels that from arrest records, but neither of these fit with pressure as assessed by poacher interviews. That suggests to me that Dennis' work is probably the most accurate, but he's not yet published these studies, so for now you can only read about it here. The vast majority of other work is based on poacher surveys, and we also know that when you compare what poachers say the meat is with what the DNA tells you, you get remarkably little agreement too.All of this suggests to me that we need to take the research based on poacher surveys with a large pinch of salt. So, with that in mind,  I'm going to focus more on the declines that are reported to be associated with bushmeat, rather than the more poacher-based surveys.

 Let's start at the source. Bushmeat across Africa seems to be increasingly coming from inside protected areas. This is presumably increasing as the number of animals available outside protected areas is declining almost everywhere, presumably from a combination of illegal hunting and habitat destruction. Now, whilst a lot of bushmeat hunting uses fairly non-selective hunting methods - snares being very popular - that doesn't mean the hunters don't have target species in mind. In fact, surveys suggest they try to be quite selective,
Poacher, or traditional hunter-gatherer? Hadza nr Eyasi
but as their favoured targets decline they'll swap to other species and trends vary. Recently, for example, there's been a surge in giraffe snaring across Tanzania and southern Kenya - though no-one I've spoken to seems to know where the meat is heading as it's not much consumed locally. This focused effort can lead to very big declines in target species - giraffe are one of very few species currently on the decline in the Serengeti ecosystem. Tim Caro (of zebra stripes fame!) reports from Katavi that poachers target giraffe, hippos and warthog, all of which are in decline in the ecosystem. And the stories in West Africa are even worse - primates and duikers are the primary focus in many of the forests and outside of protected areas the forests are largely empty, even in remote areas. This is clearly unsustainable in many cases with demand far outstripping natural regeneration rates: bushmeat hunting is a major concern across much of Africa, particularly in the west. Overall, the numbers involved are pretty staggering. 100,000 wildebeest per year in Serengeti alone, 385,000 tonnes of bushmeat in Ghana each year, Cameroon 78,000 tonnes, CAR 13,000 tonnes, DRC over 1million tonnes, Equatorial Guinea 10,000 tonnes, Gabon 11,000 tonnes, Congo 16,000 tonnes, etc. (latter figures from here). We know rather less about the totals for southern and eastern Africa, but we do know it's growing in both areas (the comparative estimates are that only 0.1% of protein in the average diet comes from bushmeat in southern Africa, whereas it's closer to 8.5% in west Africa - though I really doubt these figures are accurate, I only trust the west being bigger than the south).

Close contact with raw bushmeat is inevitable.

Those figures are enormous and impossible to understand alone. So, a little bit of context: the same central/west African countries have a human population of just over 100 million. So 150 million tons of bushmeat gives around 15kg of bushmeat per person, per year. Not so much, when for many it will be their main source of meat. Compare that with the (legal) harvest of deer in one US state in 2010 - 418,000 animals killed, with a mean body mass of c.90kg, gives a harvest of 37,000 tonnes per year, in a state with a population of 9.8 million. (I couldn't find national figures - if anyone has some I'd be fascinated! I couldn't be bothered to trawl through all the individual state reports...) That's still nearly 4kg per person, in a country that consumed 41.5 million tonnes of domestic meat in 2006, an average of 106kg of meat per person.

Still, undeniably a huge conservation issue. But it's not just that - for me the really scaring things about the bushmeat trade is the way the contact with raw or poorly cooked animal meat gives a potential source for infections to jump from species to species. For example, there's very good evidence to suggest that HIV made it's way to humans from monkeys via the eating of undercooked bushmeat, probably more than once (giving a variety of different HIV strains). What's more outbreaks of the very nasty Ebola virus and some other related Hanta viruses probably also come from contact with animals as a result of the bushmeat trade. These are scary diseases indeed. The one you've not (yet) heard about it probably monkey pox, a close relative of the now extinct small pox that has so far only made limited jumps to humans (mostly from squirrels, often popular bushmeat), but if it evolves to pass human to human more rapidly I suspect you'll soon hear about it. So there's an even darker side to the bushmeat trade than you might have imagined. And in case you think you're safe because you live in Europe or North America, bear in mind that Estimates based on a 17day intensive stop and search in a Paris airport suggested perhaps as much as 270 tons of bushmeat is illegally imported into Europe from Africa each year, including several threatened species. Monkeys sold at about $5 each in Congo fetch over $100 in Europe. Chicago seems to be the import hub into the US, in case you where interested! And these American samples at least, did contain several types of nasty viruses.

Not much meat on a squirrel, but you might get Monkey pox!
So what are the opportunities here? Well, there are many countries where hunting is controlled and can provide a sensible source of both income and protein. (See the comparison above with the US deer harvest.) The key is, of course, sustainability. If the trade is adequately controlled, there's a real potential for income here –about $5million per year could come from sustainable harvest of the Serengeti wildebeest, without even seeing a population dip. That's surely something to think about. What's more, there are cultural considerations here – many tribes traditionally hunt wild animals, some, like the Hadzabe in Tanzania, still rely mainly on bushmeat for their protein requirements. By calling all such hunting poaching, we effectively make a way of life, indeed a whole culture, illegal (whilst simultaneously allowing rich (and usually foreign) hunters to shoot the same animals in game reserves next door). This is clearly a problem and control of the bushmeat trade must be seen as the way to go. One option is to see protected areas as a 'no-take' refuge from which surplus animals are allowed to disperse into areas where they can be hunted legally, but for that to work these still needs to be effective control methods. And how to do that, in rural Africa? Well, there's another problem... I'm interested in ideas!

PS for the record, I'm a vegetarian...

References: Macdonald, D., Johnson, P., Albrechtsen, L., Seymour, S., Dupain, J., Hall, A., & Fa, J. (2012). Bushmeat trade in the Cross–Sanaga rivers region: Evidence for the importance of protected areas Biological Conservation DOI: 10.1016/j.biocon.2011.12.018  

Knapp, E., Rentsch, D., Schmitt, J., Lewis, C., & Polasky, S. (2010). A tale of three villages: choosing an effective method for assessing poaching levels in western Serengeti, Tanzania Oryx, 44 (02) DOI: 10.1017/S0030605309990895  

Chaber, A., Allebone-Webb, S., Lignereux, Y., Cunningham, A., & Marcus Rowcliffe, J. (2010). The scale of illegal meat importation from Africa to Europe via Paris Conservation Letters, 3 (5), 317-321 DOI: 10.1111/j.1755-263X.2010.00121.x  

Wilkie, D., & Carpenter, J. (1999). Bushmeat hunting in the Congo Basin: an assessment of impacts and options for mitigation Biodiversity and Conservation, 8 (7), 927-955 DOI: 10.1023/A:1008877309871  

Smith, K., Anthony, S., Switzer, W., Epstein, J., Seimon, T., Jia, H., Sanchez, M., Huynh, T., Galland, G., Shapiro, S., Sleeman, J., McAloose, D., Stuchin, M., Amato, G., Kolokotronis, S., Lipkin, W., Karesh, W., Daszak, P., & Marano, N. (2012). Zoonotic Viruses Associated with Illegally Imported Wildlife Products PLoS ONE, 7 (1) DOI: 10.1371/journal.pone.0029505

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