I called my last POLEX message about bushmeat in Ghana, “Have your animals and eat them to”. I thought it was a great title, but it turns out it wasn’t mine.

About a year ago John Robinson and Liz Bennett from the Wildlife Conservation Society sent me their article called Having your wildlife and eating it too: an analysis of hunting sustainability across tropical ecosystems, published in Animal Conservation. When I wrote my message I’d forgotten that, but the title clearly stuck in the back of my mind.

In any case the Robinson and Bennett piece helps put the Ghana article in a broader perspective. Robinson and Bennett reviewed studies from all over the African, Asian, and Latin American tropics to see where hunting threatens wildlife the most. They conclude that hunting in moist forests is likely to be much less sustainable than hunting in dry forests, humid grasslands, forest fallows, and mixed patches of pasture and forests.

There are several reasons for that. Antelope, deer, and other ungulates have lots of meat and thrive in grassy open areas. Many of these species reproduce pretty fast; so you can catch 15-20% of them each year without running out. Opener areas also have many large rodents, particularly in Latin America, and they multiply even faster.

In contrast, monkeys and sloths are more important in moist forests, where much of the food is up in the trees. They have less meat and breed slower than rodents or ungulates. Many of the leaves in these forests have compounds that protect them from animals. Whereas each square kilometer of grasslands where it rains more than 500 millimeters per year can support a mammal population weighing 15 to 20 tons, a square kilometer of rainforests rarely supports more than three tons.

In theory, opening up forests by logging or shifting cultivation could actually increase animal stocks and the availability of meat. Studies show deer and antelope populations decline right after logging, but then increase markedly. However, don’t jump to conclusions because logging is often associated with other activities that endanger wildlife such as permanent agriculture and commercial hunting, so populations could easily decline. You are also likely to lose the largest animals and those that breed most slowly.

So whether you look just at West Africa or all across the tropics the message seems similar. Hunting threatens some species and ecosystems much more than others. Bushmeat policies should consider that.