FLORISTIC ANALYSIS OF GRAZING LAND IN QUERETARO, MEXICOFT ANALISIS FLORISTICO DE UN PASTIZAL DEL ESTADO DE QUERETARO, MEXICO

摘要

A floristic study of grassland from the state of Queretaro, Mexico is presented. In this grassland, three vegetation associations (grassland-oak, cactus-Acacia-grassland, and open grassland), 41 families, 111 genera, 142 species, 8 varieties, and 3 subspecies were recorded. Asteraceae, Fabaceae and Poaceae are families with the greatest species richness. Of the total taxa, 92% were considered native, 8% introduced, 27% endemic to Mexico, 2% naturalized, and 39% weedy or invasive. Weedy plants were indicative of disturbed regions, overgrazed areas, secondary vegetation, and areas of soil erosion. Eleven growth forms were identified within the grassland, with herbaceous species representing 53% of the species richness, and along with the shrubs and the rhizomatous individuals, representing almost 85% of the grassland flora. In spite of the location, area and intensive overgrazing, this grassland displays a substantial richness of biological forms and a high level of endemism and native species. At present, the grassland is showing signs of ecological degradation due to intensive over use of the land.