Environmental Engineering Reference
In-Depth Information
agro-biodiversity are long term in nature. To the extent that they reside in the migration
patterns of traditional farmers, we know that families do not generally abandon the land
en masse but rather export labor, generally younger family members, over time, sustain-
ing the homestead with remittances from migrant family members. Given the legal rights
in Mexico associated with maintaining an active farm, there is an incentive to keep the
land planted by keeping some family members at home. Thus,
gures on production or
planted area or even migration can mask trends that are leading to the gradual loss of tra-
ditional knowledge in the process of seed selection, which is the basis for the ongoing evo-
lution and stewardship of maize genetic diversity.
One recent analysis using disaggregated national data, correlated with data on maize
diversity, suggested there is cause for concern. Those farmers employing the greatest
diversity of native seeds were found to su
fi
er the highest levels of poverty, and this has
remained true from 1990 to 2000. These farmers, who represented two-thirds of Mexico's
maize producers in 1990, expanded the area planted in maize since 1990, by 26 percent
and 33 percent. Output has increased as well, although susceptibility to crop failure
remains highest for this group, suggesting that they are bringing more marginal land
under cultivation in order to cope with rising economic pressures. Also consistent with
previous analysis is the
ff
nding that international migration remains most intense not for
the poorest, most diverse producers but for those showing relatively low diversity and
slightly lower poverty rates. But internal migration is common for poorer producers, who
may well be migrating to Mexico's modern horticulture
fi
fi
elds initially, then moving on to
the USA when they earn enough to a
ff
ord the trip (Nadal and Wise, 2004).
ndings should serve as a warning to those who would conclude that agro-
biodiversity in maize is secure. The long-term expulsion of family members from the
households of those farming the most diverse varieties of maize is likely to interrupt the
transmission of local knowledge, undermining the seed selection upon which agro-
biodiversity depends. By all accounts, stagnation or decline in Mexican agriculture and in
other sectors of the Mexican economy has limited the options available to farmers
su
These initial
fi
ects of low maize prices. This may have slowed the feared exodus from tra-
ditional maize, but it may not have prevented it.
Paradoxically, things could get worse for agro-biodiversity if things get better for the
Mexican economy. Better opportunities elsewhere - in agriculture, in the Mexican service
sector, or in the USA - could o
ff
ering the e
ff
er traditional maize farmers viable alternatives to pro-
ducing for subsistence or selling maize in the market at the prevailing low prices.
The second threat to maize diversity is the contamination of traditional
ff
elds by GM
corn from the USA. Mexico has banned the cultivation of GM maize since 1998. Yet
studies have veri
fi
ed the presence of Bt and herbicide-tolerant transgenic traits in tradi-
tional landraces in several states, leading to widespread fears that such gene
fi
ow from
GM varieties to landraces may be more rapid and widespread than previously thought. It
is widely assumed the contamination came from US grain, which enters Mexico unsegre-
gated and unlabeled, and until recently was distributed in rural areas as food by a gov-
ernment anti-poverty program. Unwitting farmers are presumed to have experimented
with the grain as seed, and the pollen contaminated traditional varieties.
An exhaustive study by the Commission for Environmental Cooperation, the agency
set up by NAFTA's side agreement, concluded that the threat to maize diversity from GM
contamination is neither imminent nor negligible. Experts highlighted the uncertainty of
fl
