Flora de la cima de la Mesa Alta, Jerez, Zacatecas, México

Abstract

A floristic inventory on summit of the Mesa Alta was conducted; which is located 5 km northeast of El Cargadero town, in the municipality of Jerez in the central region of Zacatecas state, Mexico. The maximum elevation of the Mesa Alta is 2,750 m. Floristic similarity between the different slopes of the summit was evaluated. Geographical distribution patterns were also studied. The results show that the flora consists of 61 families, 157 genera and 237 species. Based in the geographic exposure, the largest number of species found at the summit (163 species), followed by the western slopes (122), north (56), south (41) and east (40). None of these floras is grouped with more than 50 % similarity. The geographical distribution of flora shows that Ninety-five species of the studied flora have Neotropical ancestry, 77 are native to Mexico and 65 have Holartic ancestry. Two species are reported in NOM-059-SEMARNAT-2010, Dasylirion acrotrichum and Echinocereus pulchellus. The floristic richness of the top of the Mesa Alta is similar to other areas of the country with coniferous forests. The difference between the slopes and summit is related to its specific characteristics of topography, slope, soil, and exposure time. The results support the proposal to enact the mountain range in which Mesa Alta is as a Natural Protected Area, and provide the basic information for future flora comparisons among the peaks in Zacatecas.