Pasture conversion, private ranchers, and the invasive exotic buffelgrass (pennisetum ciliare) in Mexico's Sonoran Desert

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This research examines the role of private ranchers in Sonora, Mexico, in regional-scale landscape change involving an invasive species. The arid rangelands of Sonora are a center of modern commercial cattle ranching, where the exotic buffelgrass (Pennisetum ciliare) is the favored species for the extensive conversion of native range vegetation to pasture. The land management decisions of private ranchers, the primary agents of pasture conversion, are examined amid peculiar challenges and opportunities presented by buffelgrass in the context of the modernization of Sonoran ranching. An environmental history of buffelgrass in the region is coupled with qualitative and quantitative interview data, which are subjected to binary logistic regression modeling. Statistical results show rotational grazing as the strongest driver of pasture conversion, followed by native forage scarcity. Land entitlement, government support, hobbyism, and belief in buffelgrass as long-term drought mitigation are insignificant. Interview data reveal diverse expressions of agency among Sonoran private ranchers, and historical research illustrates the structural context that conditions land-use decisions. Ultimately, pasture conversion arises not from state sponsorship but from complex interactions among desert ecosystems, ranchers, and the institutions that mediate their engagements with the state and an international political economy. This research confirms the utility of analyzing changing landscapes as coupled human-environment systems and questions the utility of an agency-structure dichotomy in land-use change explanations. © 2011 by Association of American Geographers.

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Annals of the Association of American Geographers

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