Dasylirion cedrosanum Trelease (Nolinaceae) Density Varies Depending on Elevation and Slope in the Northeast of Zacatecas, Mexico

摘要: There is little or no specific and concise information on the ecological conditions which constrain distribution, abundance, density of Dasylirion cedrosanum Trelease keeping in mind that such knowledge indispensable to promote support plantations reforestation programs order confront consequences a possible depletion natural populations. Therefore, aim this study was evaluate D. as related factors latitude, longitude, altitude, slope, soil texture fractions, pH, electric conductivity, available nitrogen phosphorus contents, organic matter content xerophytic scrub northeast Mexico’s state Zacatecas. Data from 41 square–shaped sampling units 1.000 m 2 each an area 2.422.2 ha where altitude varies 2.000 2.356 masl, slope inclination changes moderate (5.5%) steep (44.2%) analyzed through linear relationships, quadratic functions, principal components analysis. Results provide compelling evidence about depends elevation, inclination, silt sand contents. A triangularshaped dispersion observations when plotted against soil, sand, contents appreciated. significant humped trend suggest sites having slopes around 20%, although it could be 10 30% range, provides better habitat for species. plants are scarcer, is, present at low minimum densities (< 259 ha-1) sampled characterized by high