Alejandro López-Feldman

Does Migration Make Rural Households More Productive? Evidence from Mexico

Abstract The migration of labour out of rural areas and the flow of remittances from migrants to rural households are an increasingly important feature of less developed countries. This paper explores ways in which migration influences incomes and productivity of land and human capital in rural households over time, using new household survey data from Mexico. Our findings suggest that a massive increase in migration to the United States increased per-capita incomes via remittances and also by raising land productivity in migrant-sending households. They do not support the pessimistic view that migration discourages production in migrant-sending economies, nor the view implicit in separable agricultural household models that migration and remittances influence household incomes but not production.

Does natural resource extraction mitigate poverty and inequality? Evidence from rural Mexico and a Lacandona Rainforest Community

The potential importance of natural resources for the livelihood of poor rural households has long been recognized but seldom quantified and analyzed. In this paper we apply poverty and inequality measures to national and community level data sets to explore the impacts of resource extraction on rural welfare. Our findings suggest that natural resource extraction reduces both income inequality and poverty. Results from a simulation analysis at the community level indicate that poverty may be reduced, in the short-run, by increases in the price of a non-timber forest product

Genetic erosion in maize’s center of origin

Significance Unlike germplasm banks, on-farm conservation allows crops to evolve continuously in response to changing conditions. Agricultural adaptation to climate change, emerging pests, and diseases thus depends on conserving crop genetic diversity in situ. However, increasing awareness of these issues has not translated into effective conservation policies. We find that previous assessments of on-farm maize diversity in Mexico are flawed and conceal widespread genetic erosion that could thwart current food security strategies for climate adaptation. Unable to mitigate declining yields by recourse to diversity, farmers might abandon agriculture, leading to a vicious cycle of yield and diversity losses. A reassessment of the conservation status in other centers of crop diversity is similarly urgent but could take a decade given data requirements. Crop genetic diversity is an indispensable resource for farmers and professional breeders responding to changing climate, pests, and diseases. Anecdotal appraisals in centers of crop origin have suggested serious threats to this diversity for over half a century. However, a nationwide inventory recently found all maize races previously described for Mexico, including some formerly considered nearly extinct. A flurry of social studies seems to confirm that farmers maintain considerable diversity. Here, we compare estimates of maize diversity from case studies over the past 15 y with nationally and regionally representative matched longitudinal data from farmers across rural Mexico. Our findings reveal an increasing bias in inferences based on case study results and widespread loss of diversity. Cross-sectional, case study data suggest that farm-level richness has increased by 0.04 y−1 nationwide; however, direct estimates using matched longitudinal data reveal that richness dropped −0.04 y−1 between 2002 and 2007, from 1.43 to 1.22 varieties per farm. Varietal losses occurred across regions and altitudinal zones, and regardless of farm turnover within the sector. Extinction of local maize populations may not have resulted in an immediate loss of alleles, but low varietal richness and changes in maize’s metapopulation dynamics may prevent farmers from accessing germplasm suitable to a rapidly changing climate. Declining yields could then lead farmers to leave the sector and result in a further loss of diversity. Similarities in research approaches across crops suggest that methodological biases could conceal a loss of diversity at other centers of crop origin.

Reply to Brush et al.: Wake-up call for crop conservation science

We strongly concur with Brush et al. (1) regarding the urgency for a new generation of studies (2), but reject claims that our findings are unsupported and our comparisons false, a misperception that could delay adequate academic and policy responses. First, spurious or not, it is not our interpretation that we put to the test but that of influential scholars who, notwithstanding studies’ design and methodological differences, conclude that “there is increasing evidence that small-scale farmers throughout the world, and especially in areas of crop domestication and diversity, continue to maintain a diverse set of crop varieties” (3) and “after thirty years of crop collection and research … the concept of genetic erosion remains more a presumption of what is likely to occur than a demonstrated fact” (4).

Inexplicable or simply unexplained? The management of maize seed in Mexico.

Farmer management of plant germplasm pre-dates crop domestication, but humans’ role in crop evolution and diversity remains largely undocumented and often contested. Seemingly inexplicable practices observed throughout agricultural history, such as exchanging or replacing seed, continue to structure crop populations across the developing world. Seed management practices can be construed as events in the life history of crops and management data used to model crop demography, but this requires suitable quantitative data. As a prerequisite to addressing the causes and implications of maize seed management, we describe its patterns of variation across Mexico by drawing from the literature and new analysis. We find that rates of seed replacement, introduction and diffusion differ significantly across regions and altitudinal zones, but interactions among explanatory factors can obscure patterns of variation. The type, source, geographic origin and ownership of seed help explain observed rates. Yet, controlling for the characteristics of germplasm barely reduces interregional differences vastly exceeding variation across elevations. With few exceptions, monotonic altitudinal trends are absent. Causal relationships between management practices and the physical environment could determine farmers’ wellbeing and crop conservation in the face of climate change. Scarce and inconsistent data on management nevertheless could prevent an understanding of these relationships. Current conceptions on the management and dynamics of maize diversity are founded on a patchwork of observations in surprisingly few and dissimilar environments. Our estimates of management practices should shed light on differences in maize population dynamics across Mexico. Consistency with previous studies spanning over a decade suggests that common sets of forces are present within large areas, but causal associations remain unknown. The next step in explaining crop diversity should address variation in seed management across space and time simultaneously while identifying farmers’ values and motivations as underlying forces.

Maize (Zea mays L.) management in Yaxcaba, Yucatan, during the twentyfirst century’s first decade is consistent with an overall loss of landrace diversity in southeast Mexico

The status of genetic resource conservation in centers of crop diversity remains disputed. Recent case-study findings of persistent maize diversity in Yaxcaba, Yucatan, a municipality in southeast Mexico, have raised questions on earlier reports of widespread losses across the crop’s center of diversity in Mexico. We break down patterns in maize varietal richness in southeast Mexico to show that temporal trends in Yaxcaba are subsumed under spatial variation in this broader region and consistent with an overall loss of diversity. Persistence of diversity in Yaxcaba can be explained by conditions that allowed subsistence farmers to continue sowing land even as maize prices dropped, but these conditions may be rare in Mexico and likely to change. Yaxcaba emerges as a rare community of exceptional diversity from which valuable policy lessons can be drawn. We find that gaps and omissions in the Mexican Government’s strategy for maize conservation have excluded Yaxcaba and likely resulted in an ineffective intervention elsewhere in the Peninsula. An integrated-systems perspective should help us develop a coherent strategy for resource conservation and climate adaptation based on more efficient and equitable instruments.