Environmental Engineering Reference
In-Depth Information
7
The Evolution of Foraging
A reliable quantii cation of the resulting impact on the biosphere is impossible, as
we lack any realistic assessments of total populations engaged in specii c foraging
activities, but there can be no doubt that in parts of several biomes (in the richest
tropical rain forests and in boreal forests), it remained marginal for millennia. The
relative richness of the coastal aquatic zoomass meant that some maritime regions
were among the most intensively exploited environments. Cold and hot deserts
and their neighboring transitional zones to more vegetated environments were at
the other end of the diversity spectrum: a paucity of both collectible plants and
larger species whose hunting could supply enough meat for small bands of foragers
kept the population densities very low, and with no possibility of converting such
lands to permanent farming, these areas were also among the last places where
foraging persisted into the twentieth century and could be studied by modern
anthropologists.
That the continuous gathering of preferred plant species and the hunting of
favorite large, slowly reproducing animals could exert notable local and regional
effects on the exploited ecosystems is self-evident. But the idea that hunting alone—
by relatively small populations equipped with simple wooden and stone weapons—
could be the only, or at least the primary, reason for a relatively rapid extinction of
large terrestrial mammals at the end of the Pleistocene remains controversial. While
it is easy to advance arguments in favor of this interpretation and to construct theo-
retical models claiming to prove the case, it is another matter to produce convincing
evidence and to explain the many realities that do not conform to that interpreta-
tion. In contrast, there is no doubt about the extensive and recurrent impact of
deliberately or accidentally set i res on the biosphere's productivity.
The extent of foraging in traditional agricultural societies was highly time- and
place-dependent: rewarding opportunities for hunting animals and collecting wild
plants were rather rapidly exhausted on the treeless alluvial plains that became the
