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Sotol (Dasylirion leiophyllum) grows in the Chihuahan Desert in the north of Mexico and south of the United States. The stem of this species is used to produce a liquor widely known as sotol. A field sampling and a laboratory analysis were carried out to determine the influence of the rainy season, altitude, topography, and aspect over the soluble solid content (°Brix) and bromatological variables of mature plants of sotol in Chihuahua, Mexico. Analyses of variance and Tukey tests were performed. The rainy season and altitude showed significant statistical influence (p ≤ 0.05) on the total soluble solids content; meanwhile, only altitude showed a significant effect on the bromatological variables (p ≤ 0.05). According to the results of the Tukey tests (p < 0.05), sotol plants have the highest concentrations of soluble solid contents before the rainy season (25 °Brix) and at sites with altitudes lower than 1300 m (25.95 °Brix). In addition, the means of raw protein and carbohydrates content were the highest in plants living at altitudes lower than 1500 m, at 1.93% and 31.74%, respectively. Meanwhile, topography, aspect, and the interactions of the evaluated factors did not show significant influence (p ≤ 0.05) over the total soluble solid content, nor over the bromatological variables studied. [ABSTRACT FROM AUTHOR]

The understanding of the hydrological processes in transitional zones between semi-arid and temperate ecosystems is essential since these areas are particularly sensitive to changes in precipitation and land cover. The objectives were to (1) determine the most critical factors in the generation of surface runoff during one rainy season; and (2) analyze the effect of different rainfall variables and soil moisture on the amount of surface runoff. The study area is in a semi-dry forest in the state of Chihuahua, Mexico. Vegetation, soil, and precipitation variables were monitored on three micro-catchments (0.19–0.27 ha) in 2018. Maximum 30-min rainfall intensity, rainfall depth, and soil moisture were the main variables controlling surface runoff. Rainfall intensity was better related to the amount of surface runoff, with an increase in runoff when rainfall intensities were greater than 25 mm h−1. The highest runoff coefficients (10%) occurred only when rainfall intensity exceeded 30 mm h−1. Similarly, surface runoff was only activated when rainfall depth exceeded 20 mm, or when the maximum volumetric water content by rainfall event exceeded 30%. Only 10% of storms exceeded these thresholds, indicating the difficulty of runoff generation in transitional zones. The interception (36%; s.d. = 30.7%), and the drastic decrease in soil moisture after each storm, suggest that more than 90% of the rainfall was lost by evapotranspiration. Our findings suggest that the groundwater recharge in a given year in these transitional zones is highly related to the number of low intensity and long duration rainfall events. [ABSTRACT FROM AUTHOR]

In this study, the transitions of land use that occurred in the urban and peripheral areas of Chihuahua City, Mexico, were determined for the period 1989-2014. Landsat TM and OLI scenes, as well as the method of Markov Chains (MC) were used. Grasslands and Shrublands were the land uses that experienced the highest pressures for land use. Grasslands occupied 23.5% of the area in 1989, decreasing to 16.01% in 2014. Likewise, Shrublands were reduced from 54.53% to 48.06%. The areas occupied by Croplands, Oak forest,Water bodies and Riparian vegetation stayed in general constant. In contrast, the urban area increased from 13.6% to 28.6% of the total area studied. In addition, projections of land use for 2019 and 2024 were generated through the method of MC and Cellular Automata (CA). According to the projections, validated with an agreement of 0.90, the Human settlements would continue to expand, occupying 38.57% by 2019 and almost half of the studied territory (47.33%) by 2024. The ecosystems with the highest pressure for land use change will continue to be the Grasslands and Shrublands. By 2024, the former would lose 15.8% while the latter would lose 16.7% of the area. These methods are valuable for urban planning and the results could support growth plans for Chihuahua City, Mexico, with a sustainable approach. [ABSTRACT FROM AUTHOR]

This study developed a GIS-based framework for the zoning of land suitability for grassland conservation (LSGC) in the Central Valleys of Chihuahua, México. For that, a Geographic Information Systems (GIS)-based multicriteria evaluation techniques with weighted overlay (MCE-WO), and a fragmentation analysis were performed. The framework for LSGC consisted in the development of four scenarios: Nonintensive Agriculture, Intensive Agriculture, Urban, and Rural. The LSGC classes defined with the MCE-WO technique were: Very high, High, Moderate, Low, and Very low land suitability. Results showed that the zone with a high suitability covered the largest area in the four scenarios with a surface of 44,264 km2. The zones with low and very low suitability were concentrated mainly in the central region of the study area. At the landscape level, fragmentation of LSGC showed the Nonintensive Agriculture and the Rural scenarios with the highest Number of patches (54,640 and 46,210, respectively). The fragmentation of LSGC, under the scenarios evaluated, was mainly due to land opening for agriculture and to the influence of rural communities. The integration of GIS with MCE-WO is useful and effective for the evaluation of LSGC. This tool can provide a solid source of information for decision-makers regarding planning of land use to mitigate grasslands degradation. [ABSTRACT FROM AUTHOR]

Soil erosion is considered one of the main degradation processes in ecosystems located in developing countries. In northern Mexico, one of the most important hydrological regions is the Conchos River Basin (CRB) due to its utilization as a runoff source. However, the CRB is subjected to significant erosion processes due to natural and anthropogenic causes. Thus, classifying the CRB's watersheds based on their erosion susceptibility is of great importance. This study classified and then prioritized the 31 watersheds composing the CRB. For that, multivariate techniques such as principal component analysis (PCA), group analysis (GA), and the ranking methodology known as compound parameter (Cp) were used. After a correlation analysis, the values of 26 from 33 geomorphometric parameters estimated from each watershed served for the evaluation. The PCA defined linear-type parameters as the main source of variability among the watersheds. The GA and the Cp were effective for grouping the watersheds in five groups, and provided the information for the spatial analysis. The GA methodology best classified the watersheds based on the variance of their parameters. The group with the highest prioritization and erosion susceptibility included watersheds RH24Lf, RH24Lb, RH24Nc, and RH24Jb. These watersheds are potential candidates for the implementation of soil conservation practices. [ABSTRACT FROM AUTHOR]