Principales detonantes y efectos socioambientales del boom del aguacate en México

ABSTRACT In the time of globalization, the growing global food trade can have a major effect on every corner of the world. These include uncertain effects on the climate, use of land, socioeconomic concerns, and political and cultural conditions for exporting countries. In this study we performed a literature review to identify the evidence of the economic, environmental and social effects as a result of recent avocado plantation expansions in the avocado-producing area of Michoacan, Mexico. Mexico is the largest avocado producer in the world and Michoacan represents more than 80% of the total planted area of the country. The results show a greater wealth for producers and a small group of packinghouses due to avocado industry. There are also environmental concerns due to rapid land-cover changes and the overuse of pesticides that secrete into soils and groundwater with cascading effects for local people. Our results highlight the economic, environmental and social effects of the avocado industry; however, many gaps remain in our understanding. In this study we identified gaps in the current research and present some directions for future research. RESUMEN En la era de la globalización el creciente intercambio internacional de productos alimenticios puede generar efectos inciertos en todos los rincones del mundo. Entre éstos, el clima, uso del suelo, condiciones socioeconómicas, políticas y culturales para el país exportador. En este estudio hicimos una revisión de la literatura para identificar evidencias de los efectos económicos, ambientales y sociales que han resultado de la expansión del cultivo de aguacate en Michoacán, México. México es el mayor productor de aguacate en el mundo y Michoacán concentra más del 80% de la superficie total sembrada del país. Los resultados indican que existe una mayor riqueza material para los productores de aguacate y para un grupo reducido de empresas transportistas, pero también existen repercusiones ambientales por el cambio de uso de suelo acelerado y uso excesivo de pesticidas que dañan los recursos hídricos y erosionan los suelos, originando un efecto cascada para la población local. Los resultados muestran evidencias de que la producción de aguacate tiene impactos económicos, ambientales y sociales; sin embargo, existe un vacío de investigación para comprender estos efectos a mayor profundidad. El artículo identifica áreas prioritarias que podrían ser exploradas en investigaciones futuras

Análisis hidrometeorológico de las estaciones de la cuenca del lago de Cuitzeo

El análisis de datos hidrometeorológicos de series de tiempo es una herramienta apta para analizar la evolución del clima pasado y presente. El objetivo de este trabajo es analizar el comportamiento de las series de tiempo de los datos de precipitación, temperatura y escurrimiento de las estaciones hidrometeorológicas ubicadas en las subcuencas (y algunas en sus cercanías) de Cointzio, Queréndaro y San Marcos, localizadas dentro de la cuenca del lago de Cuitzeo, Michoacán. En primera instancia se presenta una descripción de los datos de temperatura utilizando climogramas; como se esperaba, los mismos registraron, para casi todas las estaciones, las mayores temperaturas durante los meses de abril, mayo y junio. El análisis de tendencia de precipitación, temperatura y escurrimiento se realizó con la prueba no paramétrica de Mann-Kendall. Esta técnica ha sido ampliamente utilizada para probar aleatoriedad contra tendencias en los datos climáticos de las series de tiempo. El análisis de tendencia indica que la temperatura media en la estación de Morelia tiende a aumentar de manera significativa tanto sus valores mensuales como en el valor medio anual; mientras que Cuitzeo y Huingo tienden a reducir sus temperaturas en forma significativa. Para las precipitaciones anuales indica que las estalaciones de Huingo y Jesús del Monte han presentado un aumento estadísticamente significativo

Evidence of volcanic activity in the growth rings of trees in the Tacaná Volcano, Mexico-Guatemala

Volcanic activity can have a significant effect on the growth and survival of trees. The objective of our research was to analyze the effects of the 1855–1856 eruption of the Tacaná volcano and the ashfall from the 1902 eruption of the Santa María volcano, Guatemala, on the radial growth of trees at Tacaná. Dendrochronological sampling was carried out on sites covered by Pinus hartwegii Lindl., and a ring-width chronology was built using 102 increment cores from 75 trees. The ring-width chronology shows two statistically significant suppression events. One of these events occurred from 1857 to 1868 and was potentially caused by the historic eruption of Tacaná (1855–1856). The second suppression event occurred from 1903 to 1908, during which tree growth was affected 1 year after the ashfall caused by the 1902 eruption of Santa María. The growth suppression did not have the same magnitude in all sampled trees and may be related to the thickness of the ash layer deposited around each tree. For the first time, we show that tree growth at Tacaná is reduced by ashfall from volcanic eruptions. Our results may contribute to the evaluation of risks associated with the volcanic activity of the Tacaná volcano.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Análisis espacial del paisaje como base para muestreos dendrocronológicos: El caso de la Reserva de la Biosfera Mariposa Monarca, México

Landscape spatial analyses using Remote Sensing (RS) and Geographic Information Systems (GIS) has been scarcely used to indentify sites with dendrochronological potential. For this study, we designed a protocol to identify areas with climatically sensitive trees, based on the spatial analysis of landscape biophysical features. The protocol included the analyses of slope angles, slope aspect, and the distribution of Land Cover and Land Use (LCLU) using RS and GIS tools. The protocol was validated through dendrochronological sampling in two adjacent sites. Analyses of tree ring widths were done using COFECHA and dplR. Results suggest that sensitive trees grow in 18% of the Monarch Butterfly Biosphere Reserve. Trees from the two sites differed in age, diameter, and mean ring width. Our protocol allowed us to identify sites with long-lived and sensitive trees as represented by the high inter-annual variation found in tree ring widths. The spatial analysis of biophysical variables prior to sampling enables the identification of sites with sensitive trees implying the elimination of less samples. Our proposed protocol is efficient and can be used in other areas.El análisis espacial del paisaje, con técnicas de Percepción Remota (PR) y herramientas de Sistemas de Información Geográfica (SIG), es un procedimiento poco usado en la identificación de sitios potencialmente idóneos para el muestreo dendrocronológico. En el presente trabajo se diseñó un protocolo para identificar áreas con árboles climáticamente sensibles, empleando un análisis espacial de variables biofísicas. El diseño consistió en el análisis de la pendiente del terreno, la orientación de laderas y la distribución de Cobertura Vegetal y Uso de Suelo (CVUS), mediante el uso de técnicas de PR y herramientas de SIG. El protocolo se validó mediante un muestreo dendrocronológico en dos sitios adyacentes. Los análisis estadísticos del ancho de anillos de crecimiento se realizaron mediante los programas COFECHA y dplR. Los resultados indicaron que 18% de la Reserva de la Biosfera Mariposa Monarca presenta características aptas para colectar muestras dendrocronológicas sensibles a variación climática. Los análisis estadísticos indican que existen diferencias entre los dos sitios en edad de árboles, diámetro y ancho de los anillos. La propuesta del diseño de muestreo permitió ubicar sitios con árboles longevos y sensibles, lo que se traduce en alta variación interanual en el ancho de anillos. El análisis espacial de variables biofísicas previas al muestreo dendrocronológico, contribuye a la identificación de sitios con árboles sensibles y a eliminar menos muestras. El protocolo propuesto es eficiente y puede ser replicable en otras áreas

Dendroclimatology in Latin America: A Review of the State of the Art

The application of dendrochronology for understanding climatic variations has been of great interest to climatologists, ecologists, geographers, archeologists, among other sciences, particularly in recent decades when more dendrochronological studies have been developed. We analyzed and identified the current state and recent advances in dendroclimatology in Latin America for the period 1990 to 2020. We carried out reviews in ScienceDirect, Web of Science, and Scopus databases with the keywords “dendrochronology”, “dendroclimatology”, “dendrochronology and climatic variability”, “dendroclimatology and climatic variability”, “dendrochronology and trend”, and “dendroclimatology and trend” for each Latin American country. Results show that dendroclimatological research in the last 11 years has increased and has been mainly developed in temperate climate zones (83%) and tropical or subtropical areas (17%), where conifer species have been the most used with over 59% of the studies. However, broadleaf species for dendrochronological studies have also increased in the last decade. Dendroclimatological research in Latin America has provided important advances in the study of climatic variability by defining the response functions of tree-rings to climate and developing climatic reconstructions. Our research identified areas where it is necessary to increase dendroclimatic studies (e.g., dry and tropical forests), in addition to applying new techniques such as isotope analysis, blue intensity, dendrochemistry, among other tree-ring applications

Two Centuries of Drought History in the Center of Chihuahua, Mexico

Droughts are a climatic phenomenon with local, regional, and large-scale repercussions. Historical knowledge of droughts generated by modeled data allows the development of more accurate climate reconstructions to propose better approaches for the management of hydric resources. The objective of this research was to evaluate the association of precipitation and temperature with data from the NLDAS-002 to develop a reconstruction of droughts in the center of Chihuahua, Mexico using the SPEI from tree rings. We also identified the influence of ocean–atmospheric phenomena on the reconstructed drought index. The best association among chronologies was obtained with the earlywood band and accumulated seasonal precipitation from November of the previous year to June of the current year (r = 0.82, p < 0.05) and for temperature from January to July (r = −0.81, p < 0.05). The reconstructed drought index extended from 1775 to 2017 (243 years), where seven extreme drought events were identified. We found significant correlations between the reconstructed Standardized Precipitation Evapotranspiration Index and the Pacific Decadal Oscillation (r = 0.46, p < 0.05), Atlantic Multidecadal Oscillation (r = −0.34, p < 0.05), Multivariate El Niño Southern Oscillation Index (r = 0.29, p < 0.05), and Southern Oscillation Index (r = −0.22, p < 0.05). The historical reconstruction of hydroclimatology in the center of Chihuahua is important for planning a long-term assessment and for the management of water resources shared by Mexico and the United States