Genetic Resources in Agroecosystems - Agroecology: The Ecology of Sustainable Food Systems - page 201

FIGURE 14.11 Chickens of an endangered locally adapted breed in Mexico's Yucatan Peninsula and their rustic chicken
house. School children rear and promote the chickens as part of a school Forest Garden project in the town of Cepeda. Unlike high-
yielding modern varieties, these chickens are free ranging, resistant to the hot Mayan lowlands, and are able to subsist with minimal
external inputs while providing an excellent protein complement to local diets.

and changing market conditions or consumer preferences.
Livestock breeds indigenous to particular locales often
have valuable traits such as high fertility, good maternal
instincts, disease resistance, ability to thrive on poor
quality feed, adaptation to harsh conditions, longevity, and
unique product characteristics. All of these traits are
desirable — and necessary — for low-input livestock pro-
duction, and are often missing in the widespread commer-
cial breeds. Thus, indigenous breeds of poultry, swine,
cattle, and other livestock types are crucial for sustainable
livestock production.
Despite the value of genetic diversity in livestock,
however, it is at greater risk than the genetic diversity of
our crop plants, in part, because an animal's genome can-
not easily be stored in a genebank. The FAO has estimated
that as many as 43% of the livestock breeds in the world
are threatened with extinction.
Recognizing the multiple roles that animals can play
in sustainability offers a chance to reverse this trend. As
we will see in Chapter 19, local and traditional breeds can
play a critical role in the process of reintegrating livestock

animals into crop production systems — a necessary step
in the creation of sustainable food systems.

CONCLUSIONS

Growing concern about the negative impacts of external
human inputs on agroecosystem sustainability, coupled
with regulations limiting the types of inputs farmers can
use, is bringing renewed interest in breeding defenses and
resistance back into crop organisms. This may result in
changes in the genetic basis of adaptations, but we must
also change the environmental background. If we continue
to plant large monocultures, and focus only on resistance
to particular stresses or problems, without determining
why those problems occur in the agroecosystem in the
first place, we will continue to select the very problems
we are trying to avoid (Table 14.3).
The goal of agroecology is to apply ecological knowl-
edge to the design and management of sustainable agro-
ecosystems. If we are to pursue this goal, we need to
broaden the context of our plant and livestock breeding