226 animal, vegetable, miracleDomestic herds can also carry problems into these habitats. Overgraz-
ing has damaged plenty of the world’s landscapes, as has clearing rain
forests to make way for cattle ranches. But well- managed grazing can ac-
tually benefit natural habitats where native grazers exist or formerly ex-
isted. Environmental research in North and South American deserts has
shown that careful introduction of cattle, sheep, or goats into some grass-
lands helps return the balance of their native vegetation, especially mes-
quite trees and their kin, which coevolved for millennia with large grazing
mammals (mastodons and camels) that are now extinct. Mesquite seeds
germinate best after passing through the stomach of a ruminant. Then
the habitat also needs the return of fire, and prairie dog predation on the
mesquite seedlings—granted, it’s complicated. But grazers do belong.
In northwestern Peru, in the extremely arid, deforested region of Pi-
ura, an innovative project is using a four- legged tool for widespread refor-
estation: goats. This grassless place lost most of its native mesquite forests
to human refugees who were pushed out of greener places, settled here,
and cut down most of the trees for firewood. Goats can subsist on the
seedpods of the remaining mesquites (without damaging the thorny trees)
and spread the seeds, depositing them across the land inside neat fertil-
izer pellets. The goats also provide their keepers with meat and milk, in a
place where rainfall is so scarce (zero, in some years), it’s impossible to
subsist on vegetable crops. The herds forage freely when mesquite beans
are in season, and live the rest of the year on pods stored in cement- block
granaries. These low- maintenance animals also reproduce themselves
free of charge, so the project broadens its reforesting and hunger- relief
capacities throughout the region, year by year.
We cranky environmentalists tend to nurture a hunch that humans
and our food systems are always dangerous to the earth. But when I vis-
ited Piura to study the mesquite- goat project, I could not name any mea-
sure by which the project was anything but successful. The “before”
scenario involved malnourished families in a desiccated brown land-
scape. Within a few years after receiving goats, the families still lived in
simple mud- and-lath homes, but their villages were shaded by green
oases of fast- growing native vegetation. They milked the goats, made
cheese, burned mesquite pods for cooking fuel, and looked forward to