From W. D. Hamilton
Oxford
The plants of the Colombian paramo described by Brian Homewood (“High and dry
in Colombia”, 29 June, p 34) are very like the black and white daisies of James
Lovelock’s model for Gaia. In the paramo, the espeletia (a daisy, as it happens)
makes the local world better for itself through collecting water from clouds and
also better for its ensemble since together the plants build a peaty sponge. By
releasing excess water slowly, the sponge improves the world for plants and
people down in the valley. Unfortunately, as Homewood shows, the beneficiaries
don’t always reciprocate.
This serves to highlight the main problem with Gaia. No one has yet shown why
a mobile and/or distant agent should evolve to repay beneficially. The
whole Gaia idea of evolved stability thus depends on an unstated proposition
that distant influences and mobile agents have a meagre overall influence on
local environments compared to local effects. The fact that it seems to be much
easier to get local people to protect the paramo than it is to get the
government in Bogotá to do so is entirely consistent with this
reasoning.
The same principle of local human involvement is being applied successfully
in a quite opposite kind of wetland on the same continent. As Homewood makes
clear, not all the water of the moors and snows of the great Andean arc trickles
to the Amazon, but a lot does, and most of this passes eventually into a certain
spongy patch of flooded forest in western Brazil.
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Here the Mamirauá Project based in Tefé motivates and organises
the local people, who are dependent on the floods and the forest, to protect
their own against outsiders. The principle is again working well.
However, even if local effects can be made to predominate over distant ones,
major questions about the capabilities of such multi-species ensembles remain.
How cooperative are the paramo plants—do they really help each other to
construct a sponge which then helps everyone? Though powerless against
bulldozers, can they nevertheless—physically by their peat construction,
long-term by their evolution—resist uncooperative and damaging outsider
species?
These questions have not yet had the attention they deserve from ecologists.
Understanding these kinds of superorganism, if they are such, will be crucial to
the possibility of a real science of Gaia as opposed to a myth. It may prove
crucial to the future of humanity in our super-mobile world—and even
whether we have one.
