Effects of 20 years of parceling on the condition of communal rangeland on a Mexican ejido

This study evaluated the current condition of rangeland on 18 out of 62 plots created in 1993 by parceling the communal rangeland of the El Castañón ejido (Catorce, San Luis Potosí, México). Six plots located in three different rangeland sites were analyzed: two, visually characterized as ‘good’, two as ‘poor’, and two as ‘intermediate’. The density and volumetric biomass of the preponderant perennial species were estimated after grouping them by vital form and forage value. The current state of soil cover was assessed using Canfield’s line intercept method. Estimates of the variables of vegetation structure and soil cover on the plots were then subjected to multivariate analysis (DECORANA). The hypothesis established that the concepts of site and condition of rangeland, developed for climatic grasslands in the USA, are valid for multi-stratified rangelands in the scrublands of the potosino highland. The three sites of rangeland and the visual assessments of their condition were confirmed by the results of the analyses of vegetation and soil cover. After prioritizing 17 characteristics of the 18 plots, we confirmed that the variables density and biomass by groups of species with distinct forage value, and the ratio of bare soil to ground covered with vegetation and mulch, generated adequate evaluations of the condition of these rangelands. The studied plots showed important differences in rangeland condition, after 20 years of parceling and individual exploitation. Higlights The grazing lands in the Mexican ejidos are communal, without clear rules that determine the adequate amount of livestock that can graze a given area, hence there are abuse and deterioration of up to 95% of these lands. The ejido "El Castañón y Anexos" was the first in the Potosino highlands that took advantage of the amendment to article 27 of the Constitution in 1993, to parcel out common use areas and manage them individually since then. Three rangeland sites were recognized and in each of them two parcels with better condition, two with worst condition, and two with intermediate condition, were evaluated, for a total of 18 studied parcels, out of the 62 resulting from the parcel out process. The used combination of vegetation and soil cover variables, were adequate to verify visual gradients from good to fair, and from fair to poor condition, which may allow their application in the evaluation of the condition of rangelands under similar ecological conditions.  The results obtained after the parcel out process of the communal rangelands of the "El Castañón y Anexos" ejido, may be the basis to stop and reverse the generalized desertification of the grazing lands under social usufruct.This study evaluated the current condition of rangeland on 18 out of 62 plots created in 1993 by parceling the communal rangeland of the El Castañón ejido (Catorce, San Luis Potosí, México). Six plots located in three different rangeland sites were analyzed: two, visually characterized as ‘good’, two as ‘poor’, and two as ‘intermediate’. The density and volumetric biomass of the preponderant perennial species were estimated after grouping them by vital form and forage value. The current state of soil cover was assessed using Canfield’s line intercept method. Estimates of the variables of vegetation structure and soil cover on the plots were then subjected to multivariate analysis (DECORANA). The hypothesis established that the concepts of site and condition of rangeland, developed for climatic grasslands in the USA, are valid for multi-stratified rangelands in the scrublands of the potosino highland. The three sites of rangeland and the visual assessments of their condition were confirmed by the results of the analyses of vegetation and soil cover. After prioritizing 17 characteristics of the 18 plots, we confirmed that the variables density and biomass by groups of species with distinct forage value, and the ratio of bare soil to ground covered with vegetation and mulch, generated adequate evaluations of the condition of these rangelands. The studied plots showed important differences in rangeland condition, after 20 years of parceling and individual exploitation. Higlights The grazing lands in the Mexican ejidos are communal, without clear rules that determine the adequate amount of livestock that can graze a given area, hence there are abuse and deterioration of up to 95% of these lands. The ejido "El Castañón y Anexos" was the first in the Potosino highlands that took advantage of the amendment to article 27 of the Constitution in 1993, to parcel out common use areas and manage them individually since then. Three rangeland sites were recognized and in each of them two parcels with better condition, two with worst condition, and two with intermediate condition, were evaluated, for a total of 18 studied parcels, out of the 62 resulting from the parcel out process. The used combination of vegetation and soil cover variables, were adequate to verify visual gradients from good to fair, and from fair to poor condition, which may allow their application in the evaluation of the condition of rangelands under similar ecological conditions.  The results obtained after the parcel out process of the communal rangelands of the "El Castañón y Anexos" ejido, may be the basis to stop and reverse the generalized desertification of the grazing lands under social usufruct

CONTRIBUCIÓN AL CONOCIMIENTO FLORÍSTICO DE LA SIERRA DE ÁLVAREZ, SAN LUIS POTOSÍ, MÉXICO

A floristic study was done in nineoakwoodland stands from the Sierra deÁlvarez, San Luis Potosí, characterized byhaving diverse ecological and edaphologicalcomposition. Plots of 100 m2 separated 50 meach other were located along theenvironmental gradient in each stand.Botanical samples of the whole range ofspecies were collected, processed. Identified,and stored in the herbarium of the Instituto deInvestigación de Zonas Desérticas. Thepresence or absence for a given species in thenine stands was counted as constant, accesoryand accidental. From this study the dominantfamilies were Asteraceae, Fabaceae, Poaceae,Lamiaceae, Rosaceae and Fagaceae. Newspecies without previous geografical recordare listed for San Luis Potosí. Comparing thestudied oakwoodland in San Luis Potosí,there were similarities and differences withrespect to physiography, climate, edaphology,geology, floristic composition and dominanceof species, with those found in BajaCalifornia, Nuevo León, Durango, NuevaGalicia, Aguascalientes, Querétaro, Hidalgo,Michoacán y ChiapasSe realizó un estudio florístico en nueveencinares arbóreos localizados en la Sierra deÁlvarez, San Luis Potosí, con característicasfisiográficas, edafológicas, climáticas yflorísticas diversas. En cada comunidadseleccionada se establecieron cuadros de 100m2, separados 50 m a lo largo de un gradientealtitudinal y se recolectaron especimenes detodas las especies ahí presentes, los cualesfueron procesados, identificados ydepositados en el herbario SLPM. Lasfamilias mejor representadas fueronAsteraceae, Fabaceae, Fagaceae, Lamiaceae,Poaceae y Rosaceae. Las especies de lascomunidades estudiadas se agruparon deacuerdo con su presencia o ausencia en lasnueve comunidades estudiadas, en constantes,accesorias y accidentales; su abundancia secalificó por apreciación visual. Se destacanalgunas especies útiles y de nuevo registrogeográfico para el estado de San Luis Potosí.Los encinares estudiados presentansemejanzas y diferencias fisiográficas,climáticas, edafológicas, geológicas,fisonómicas, florísticas, y en el número ydominancia de especies de encino, conalgunos encinares de Baja California, NuevoLeón, Durango, Nueva Galicia,Aguascalientes, Querétaro, Hidalgo,Michoacán y Chiapas

Ampliación de la descripción y aspectos taxonómicos de Heliopsis longipes (Asteraceae: Heliantheae)

Heliopsis longipeses la especie con mayor importancia económica de su género, pues su raíz tiene varios usos tradicionales en México. Sin embargo, aún se desconocen algunos aspectos de su morfología y biología. Los objetivos de este trabajo fueron:a)ampliar la descripción botánica de la especie,b)discutir las diferencias deH. longipescon algunos de sus congéneres, yc)documentar su fenología.Heliopsis longipesse distingue por su hábito ascendente a decumbente, hojas ovado-oblongas, el pedúnculo relativamente largo y es microendémica en las sierras de Álvarez y Gorda. Morfológicamente presenta más afinidades conH. procumbens. La reproducción deH. longipesocurre durante la época húmeda del año

Maternal dietary patterns and acute leukemia in infants: results from a case control study in Mexico

BackgroundChildhood cancer is the leading cause of disease-related mortality among children aged 5–14 years in Mexico, with acute leukemia being the most common cancer among infants. Examining the overall dietary patterns allows for a comprehensive assessment of food and nutrient consumption, providing a more predictive measure of disease risk than individual foods or nutrients. This study aims to evaluate the association between maternal dietary patterns during pregnancy and the risk of acute leukemia in Mexican infants.MethodsA hospital-based case–control study was conducted, comparing 109 confirmed acute leukemia cases with 152 age-matched controls. All participants (≤24 months) were identified at hospitals in Mexico City between 2010 and 2019. Data on a posteriori dietary patterns and other relevant variables were collected through structured interviews and dietary questionnaires. Multivariate logistic regression was employed to estimate the association between maternal dietary patterns during pregnancy and the risk of acute leukemia in infants.ResultsThe “Balanced & Vegetable-Rich” pattern, characterized by a balanced consumption of various food groups and higher vegetable intake, exhibited a negative association with acute leukemia when compared to the “High Dairy & Cereals” Pattern (adjusted odds ratio [OR] = 0.51; 95% confidence interval [CI]: 0.29, 0.90). We observed that mothers who gave birth to girls and adhered to a healthy dietary pattern during pregnancy exhibited significantly lower odds of their children developing AL compared to those who gave birth to boys [OR = 0.32 (95% CI 0.11, 0.97)]. Our results underscore the significance of maternal nutrition as a modifiable factor in disease prevention and the importance of prenatal health education

Agrobiodiversity of cactus pear (Opuntia, Cactaceae) in the Meridional Highlands Plateau of Mexico

Mexico is characterized by a remarkable richness of Opuntia, mostly at the Meridional Highlands Plateau; it is also here where the greatest richness of Opuntia variants occurs. Most of these variants have been maintained in homegardens; however, the gathering process which originated these homegardens has been disrupted over the past decades, as a result of social change and the destruction of large wild nopaleras. If the variants still surviving in homegardens are lost, these will be hard to recover, that is, the millenary cultural heritage from the human groups that populated the Mexican Meridional Highland Plateau will be lost forever. This situation motivated the preparation of a catalogue that records the diversity of wild and cultivated Opuntia variants living in the meridional Highlands Plateau. To this end, 379 samples were obtained in 29 localities, between 1998 and 2003. The information was processed through Twinspan. All specimens were identified and preserved in herbaria. Botanical keys and descriptions were elaborated. The catalogue includes information on 126 variants comprising 18 species. There were species with only one variant (Opuntia atropes, O. cochinera, O. jaliscana, O. leucotricha, O. rzedowskii and O. velutina), two (O. durangensis, O. lindheimeri, O. phaeacantha and O. robusta), five (O. joconostle and O. lasiacantha), seven (O. chavena), 12 (O. hyptiacantha and O. streptacantha), 15 (O. ficus-indica), 22 (O. albicarpa), and up to 34 (O. megacantha). Additionally, 267 common cactus pear names were related to those variants

Cambios en la cubierta vegetal y uso del suelo en el área del proyecto Pujal-Coy, San Luis Potosí, México, 1973-2000

El objetivo de este trabajo es identificar los cambios en la cobertura y uso del suelo derivados de la puesta en marcha del proyecto de riego Pujal-Coy, en el oriente del estado de San Luis Potosí, México. El estudio se basa en la interpretación y análisis de imágenes de satélite Landsat MSS y ETM+, documentos oficiales e históricos del proyecto de riego y trabajo de campo. Los resultados indican que durante la etapa inicial del proyecto más de 73 000 ha de selva baja espinosa, selva baja caducifolia y selva mediana subperennifolia fueron desmontadas. La tasa de deforestación calculada para este período fue del 11% anual. Actualmente, sólo persisten poco menos de 11 000 ha de selva en fragmentos con diferente grado de perturbación, dispersos en los tres municipios potosinos incluidos en el proyecto. La proporción del área ocupada por praderas pasó del 21% en 1973 a más del 64% en el 2000, mientras que las áreas cultivadas mantienen prácticamente la misma superficie marginal que tenían al inicio del proyecto. Estos datos evidencian el retorno inequívoco de la ganadería extensiva, que se pretendía sustituir con agricultura intensiva, y los altos costos ambientales que tuvo el proyecto