Greening the Desert - Feral: Rewilding the Land, the Sea, and Human Life - page 89

and leopards in the belief that this will enhance their chances of sur-
vival and (among early European hunters) boost the herds of game.
But one result has been an explosion in the population of olive
baboons. They inflict such damage on crops and livestock that chil-
dren have to be taken out of school to fend them off. 53 They also
transmit intestinal worms to the people whose land they enter, 54 and
appear to have reduced populations of wild game by preying on the
young animals. Similarly, when conservationists in Florida sought to
protect sea turtles by culling the raccoons which eat their eggs, they
found that it caused the opposite effect. More turtle eggs were lost, as
the raccoons were no longer eating the ghost crabs which also preyed
on them. 55
Perhaps the strangest example of these unexpected effects is the
apparent link between the decline of vultures and the spread of rabies
in India. In a remarkably short period, vultures have almost become
extinct there as an accidental result of the use of a livestock drug
called diclofenac, which turns out to be deadly to them when they eat
the carcasses. As the number of vultures has collapsed, the carrion
they ate is consumed instead by feral dogs. Their population, despite
intense efforts to control it, has risen sharply as the vultures have
declined. Dog bites are the cause of 95 per cent of the deaths from
rabies in India, and the rising population means that more people are
likely to catch the disease. 56 The vultures were also likely to have
helped control animal diseases such as brucellosis, tuberculosis and
anthrax, by clearing up infected meat.
Trophic cascades might once have dominated most ecosystems. The
old belief among ecologists that natural systems were controlled only
from the bottom up - that the abundance of plants controls the
abundance of plant eaters, which controls the abundance of meat
eaters - arose from the fact that many of the systems they were
studying had already been greatly changed by people, not least through
the reduction or extinction of top predators. Much of the richness and
complexity - the trophic diversity - of these foodwebs was lost before
it was recorded. We live in a shadowland, a dim, flattened relic of
what there once was, of what there could be again.