Range condition, tenure, management, and bio-phyiscal relationships in Sonora, Mexico

The objective of this study was to describe the relationship among range co ndition scores, tenure system, management practices and bio-physical variab les for 107 communal ejido ranches and 373 private ranches in Sonora, Mexic o. The data was obtained from assessments of range condition and recommende d carrying capacity for individual ranch units that were completed between 1973 and 1993 by the Comision Tecnica para la Determinacion de Coeficientes de Agostadero. Variables measured were range condition, land tenure (commu nal ejido or private ranch), management characteristics (human density, liv estock stocking rate, ranch size, and infrastructure condition), and bio-ph ysical characteristics (rangeland site quality and precipitation in the yea r of assessment). We used a combination of simple, univariate chi-square an alyses and more complex, multivariate ordered logistic regression analyses to assess the relationships among these variables. There was no evidence fr om the logistic regression analysis that range condition of ranches in Sono ra was related to the ejido or private tenure systems. Infrastructure condi tion was different between the 2 tenure systems, and infrastructure conditi on was positively related to range condition for both ejido and private ran ches. Based on the univariate and multivariate analyses, precipitation amou nts in the year of assessment was less for private ranches, and range condi tion on private ranches was more sensitive to precipitation than ejido ranc hes. Compared to estimates made in the 1960's and 1970's in other parts of Mexico, we found there to be less of a difference in stocking rate between the more lightly stocked private ranches and more heavily stocked ejido ran ches, and generally good condition infrastructure on all ranches. The impor tant relationship between precipitation and range condition implies that ra nge condition assessments should be done over many years to produce estimat es of trend that can be compared across wet and dry years.