I came across an interesting journal article the other day
about introducing a behavioural economics perspective to megafauna extinction. This journal is interesting not only to me as
an Economics and Geography student, but also because it suggests the value of
an inter-disciplinary perspective to environmental geography. In the 2005 paper ‘Megafauna Extinction: A Paleo-economic Theory of Human Overkill in the
Pleistocene’, Bulte et al argue that previous scientific models of overkill
concentrated only on megafauna as prey for humans, while ignoring the entire
opportunity set facing the human hunters, which is the presence of substitute
foods and behaviours. One of these is hunting small animals or minifauna.
Bulte et al have
designed a model which suggests that counter intuitively, hunting minifauna was
essential to the overkill hypothesis. Minifauna supported human populations and
allowed humans to reach critical densities which were large enough to wipe out
megafauna. Besides, hunting minifauna enabled more chance encounters with megafauna.
Complementing last week’s post, they suggest that the harsh environmental conditions
of the late Pleistocene may have triggered humans to engage in minifauna
hunting rather than more benign activities like agriculture. Minifauna did not go extinct because they
breed much more quickly than slow-breeding megafauna.
This echoes modern
day poaching behaviour in Africa. Poachers often hunt both rhinos and
elephants, and not only the more valuable rhino ivory alone, because the
probability of encountering rhinos is much smaller, making sole rhino hunting a
loss-making activity. Thus, poachers also hunt the relatively more abundant
elephants, taking rhinos as a bonus. Thus, elephant hunting is what economists
call a ‘complementary’ activity to rhino hunting, in the same way as hunting
minifauna was complementary to hunting megafauna for early humans.
This comment has been removed by the author.
ReplyDeleteHi! I do agree that we should consider the effect of hunting minifauna on the overkill hypothesis when considering megafauna extinction. However, I think that regardless of the behavioural incentives facing early human hunters, the proposition that they mainly hunted minifauna and in the process of doing so, hunt megafauna (by extension from your analogy) still poses Man as 'superpredators' and does not exonerate Man from the blitzkrieg hypothesis.
DeleteDo you happen to know if there were any changes in the extinction rates for minifauna across the pleistocene and if there were any evidence of human impact on minifauna biodiversity?
Hi Fung,
ReplyDeleteMy aim in posting this paper on Man hunting minifauna is not to exonerate Man from the blitzkrieg hypothesis. I just intend to show that species should not be viewed in isolation as ecosystems and extinction events are extremely complex! While minifauna is not within the scope of my blog, I do know what minifauna extinction certainly happened as climates changed. However, the late Pleistocene extinction event was unusual in its rapidity and species selection (i.e. megafauna was most affected). Perhaps I should do a blog post to explain this species selectivity soon!