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The post-mining land use for Navajo Mine, a large surface coal mine in northwest New Mexico, is livestock grazing. Reclamation began in the early 1970`s and has been primarily directed toward the development of a grassland with shrubs. However, none of these lands were grazed before 1994 and none have been released back to the Navajo Nation. Therefore, it is not known how these reclaimed lands will respond to livestock impacts once the lands are released. Livestock impacts include grazing, trampling, and adding feces and urine. Cattle impacts were applied in 1994 to a land that had been reclaimed in 1978, 1991 and 1992. Vegetation monitoring procedures were implemented to detect and document successful and unsuccessful impact practices for both impacted areas and areas excluded from cattle. After three impact seasons, there were similar levels of perennial plant cover, production, and density on impacted lands compared to excluded lands. Based on age structure analysis, there is a trend that establishment of seedlings is stimulated by cattle. Cattle also decrease the amount of previous years` growth of standing phytomass with a trend to stimulate new growth. It is possible that some of the previous year`s growth was reduced by cattle tramplingmore » as much as by grazing because cattle generally prefer to eat the current year`s growth before it cures. No differences in number of seedheads per plant, animal sign, plant pedestals, and soil rills could be detected after three seasons of impacting.« less |
