| It is proposed that overstocking and overgrazing by sheep during the period 1560-90 caused environmental degradation evident by the end of the 16th century in the Valle del Mezquital. Data pertaining to demographic changes, land use, land tenure and the environment (soil, vegetation, climate, and water resources) were collected in the course of archival research. This information formed the basis for the presentation and discussion of three major processes: decline of the Indian population by 90%, 1521-1600 conversion of land use to pastoralism with associated changes in land tenure, 1530-1600 and environmental deterioration, 1550-1600.The study elucidates processes involved in the growth of colonial, rural socio-economic structures during the era prior to the formation of the great estates. The move to acquire large holdings after the late 1580s is seen as a response to the reduction in carrying capacity, and an effort to maintain stock numbers and production levels, in a situation of increased demand for pastoral products.The demographic decline of the Indian communities facilitated the transference of land to the Spanish system of land use and land tenure, and by 1600 66% of the total land surface of the region had been converted to pastoralism. In the 1560s and 1570s Indian communities were displaced by the pressure of high densities of sheep, conversion of land use therefore occurred in advance of the change in land tenure. The density of animals declined during the 1580s and 1590s, but the conversion of land to pastoralism continued until some communities were left with less than the legal area of common lands. Environmental deterioration was clearly associated with overgrazing, and areas which had been intensively exploited exhibited erosion by the last decade of the century. By 1600 the carrying capacity of the region was half that reported for the 1560s and 70s and extensive pastoralism had replaced intensive pastoralism. The catchment value had also deteriorated and intensive agriculture was being abandoned. Developing forms of social organization changed during the last quarter of the 16th century from intensively worked small holdings (for sheep raising and agriculture) to extensive pastoralism and large holdings. |
