Re: Savannah and Grassland

17 Oct 1995 18:15:07 GMT

: Harry Erwin wrote:

: HE> Professor Lee Talbot spoke today in ecology class about
: HE> succession processes. As an aside, he noted that H. sapiens is a
: HE> keystone species for tropical savannah and temperate grassland.

: HE> Homo is the keystone because the alternative source of fire
: HE> (lightning- caused) is rare in temperate grassland and unknown
: HE> in tropical savannah.

: HE> The implications if he is correct are far-ranging. For example,
: HE> the ancestor of whatever hominid species first ventured out on
: HE> the open savannah had to have fire and was using it habitually
: HE> to keep his environment cleared.

: There's a leap here from Talbot's conjecture that homo is keystone
: because of the association with fire to the implication you brought
: up that homo's action was =deliberate= and keyed to preserving a
: more favorable environment. Was this also part of Talbot's
: reasoning?

Talbot went over the modern reasons for using fire. These include habitat
modification, ecosystem modification, hunting, elimination of ticks, being
able to sight enemies from a distance, and honey-hunting.

: Or is there room for the supposition that the use of fire
: led to the habitat effects, but was actually employed for other
: reasons than habitat change?

There's room.

: The idea of homo using fire for other ends and coincidentally
: causing enough wildfires to affect the environment is interesting.
: The idea of homo deliberately setting out to control the environment
: on that level would blow me away, too.

I doubt the rate of accidental wildfires would be high enough to account
for the maintenance of the savannah and temperate grassland ecosystems
over the known regions and time period.

: Evelyne Stalzer

: * RM 1.3 01313 * "What is need, compared to the path?" - Kosh

Harry Erwin
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PhD student in comp neurosci: "Glitches happen" & "Meaning is emotional"