Animals in Agroecosystems - Agroecology: The Ecology of Sustainable Food Systems - page 269

19 Animals in Agroecosystems
Livestock animals figure prominently among the many
reasons given in Chapter 1 for the unsustainability of
conventional agriculture. Confined animal feeding opera-
tions pollute the air and water, turning manure into a
problem instead of a resource; the meat industry stands
as a prime example of economic concentration, vertical
integration, and enemy of family farming; production of
soybeans and corn for animal feed takes up too high a
percentage of the world's arable land; concentrated pro-
duction of meat and animal products for human consump-
tion is energetically inefficient and ecologically harmful;
factory farming of meat tends to undermine the economic
base of rural farmers in developing countries who rely on
small-scale livestock production; trend of diets toward
more meat consumption accentuate income disparities
between rich and poor; and diseases of livestock such as
mad cow disease and avian flu threaten the human
population. Combined with the risks to human health pre-
sented by antibiotic- and hormone-laden meat and diets
too high in animal fat, these problems put livestock animals
in a bad light, making them a target for criticism among
many critics of conventional agriculture, advocates for

sustainability, and consumer activists, as well as vegetar-
ians, animal rights activists, and the like.
Certainly some of the criticism is well deserved. But
the problems lie not so much with the animals themselves
or their use as food as they do with the ways the animals
are incorporated into today's agroecosystems and food
systems. Animals can play many beneficial roles in agro-
ecosystems, and therefore make strong contributions to
sustainability. Indeed, as we will see in this chapter, the
inclusion of animals in an agroecosystem can often make
the difference in realizing ecological sustainability and
economic viability.
Relatively recently in agricultural history — around
the turn of the century in the U.S. — farms included both
livestock animals and crops as a matter of course. To use
the central concept in this chapter, crops and livestock
were integrated. The separation between crops and live-
stock that has occurred since then represents a literal dis-
integration of agriculture. This disintegration not only
threatens the ecological foundations of our food system,
but it has also fundamentally altered the terms of the
millennia-long mutualistic relationship we have developed
with our domesticated animals.
Sustainability today depends in part on reintegrating
animals and crops. It demands not the rejection of animal
protein in our food system, but a more sensible and
integrated approach to raising livestock for food that uses
agroecological concepts and principles to adapt the best
aspects of preindustrial agriculture into the postindustrial
age. In this chapter we will explore the ways in which
this reintegration can take place. The focus is not on how
to do animal husbandry sustainably, but rather on the
synergisms that derive from mixing crops and animals
and their role in moving us toward sustainability
(Figure 19.1).

THE ROLE OF ANIMALS IN ECOSYSTEMS

Animals — defined broadly as heterotrophs — are essen-
tial components of all ecosystems on earth. They consume
autotrophs (plants), transforming their biomass into ani-
mal biomass, which is eventually cycled back to autotro-
phs in the form of nutrient-rich waste and once-living
organic matter. Since agroecosystems are modified natural
ecosystems, managed for the purpose of harvesting bio-
mass, they too require animals. Of course, as the ultimate
consumers of the biomass harvested from agroecosystems,

FIGURE 19.1 An integrated farming system with organic
walnuts and chickens near Tres Pinos, CA. The mobile chicken
houses are relocated daily so chickens can feed, help in weed
management, and add manure to the soil. The walnut trees provide
shade in the hot summer. The chickens are marketed directly to
consumers, who come to the ranch to pick up their freshly slaugh-
tered orders. Walnuts are harvested in the fall. A covercrop is
grown during the winter.

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