T he aim of this study is to assess the dynamics and processes of change that have occurred in the municipality of Amanalco de Becerra, State of Mexico, through the construction of a spatially explanatory model of land use/cover changes (LUCC). The modeling process was carried out using DINAMICA EGO, a mapping tool. Land use/cover maps for the years 1989, 1997 and 2009, as well as various explanatory physical-geographical, environmental and land tenure proximity variables, were used as map inputs. The LUCC for 2020 were modelled under two scenarios: 1) the trend model, which assumes that the annual change rates for the period 1997-2009 remain unaltered, and 2) the agropastoral model, which assumes that annual deforestation rates increase because of the establishment and development of farming activities. The analysis of the absolute values of the forest category, for each year, shows a trend towards the loss of forest cover; by contrast, the annual rates of change in the forest category show a trend towards recovery-revegetation-reforestation processes, as a result of the implementation of government environmental programs. ResumenE l presente estudio tiene como propósito evaluar la dinámica y los procesos de transformación ocurridos en el municipio de Amanalco de Becerra, Estado de México, mediante la construcción de un modelo espacialmente explicativo de cambios de cobertura y uso del suelo (CCUS). El proceso de modelado se realizó con la herramienta DINAMICA EGO, utilizando como insumos cartográficos los mapas de uso de suelo y vegetación de los años 1989, 1997 y 2009, y algunas variables explicativas de proximidad, físico-geográficas, ambientales y de explotación de la tierra. Los CCUS se modelaron para el año 2020 bajo dos escenarios: tendencial y agropastoril. El escenario tendencial supone que las tasas anuales de cambio del periodo 1997-2009 se mantienen, mientras que el agropastoril presume que las tasas anuales de deforestación aumentan a causa de la apertura, establecimiento y desarrollo de actividades agropecuarias. El análisis de los valores absolutos de la categoría bosque, para cada año, muestra tendencia hacia la pérdida de la cobertura forestal; por lo contrario, las tasas anuales de cambio de esta misma cobertura tienden hacia procesos relacionados con la recuperación-revegetación-reforestación, producto de la implementación de programas ambientales gubernamentales. Palabras clave: DINÁMICA EGO, Tasas de cambio, modelo espacial.

The present document describes the experience of using a Geography Information System (GIS) tool to map the spatial distribution of the population of the State of Mexico, Mexico, for 2010. Prior to the development of the experience, dif- ferent projects, tools and products, which offered cartographic representations of the population, were presented, se- lecting one that was developed to function in Idrisi Taiga GIS. Likewise, the GIS tool and the process followed to apply it to a case study in the State of Mexico are described. The result is a raster image that shows the distribution of the population on the analyzed state, offering the possibility to identify the zones where the population concentrates and disperses and to produce an opinion from a geographic point of view on what the origin of these distribution patterns is. Among the conclusions from the analysis of results, distinguishable are the applications that the obtained image can have; for instance, the population can be estimated by basins or risk zones by only adding the values of the cells inside these zones. It is also concluded that the degree of detail expressed by the spatial distribution image of the population will depend on several factors, among them the scale and resolution of the input information and the resolution fixed for the output information

Shrimps are an important resource in coastal lagoons because they use these ecosystems for their development. Although some authors classifi ed the Penaeidae as detritivores, it was shown that their diet comprises a greater variety of food items. Many authors had reported that shrimps have a diversifi ed diet that includes several elements of the benthic community. This review describes the feeding ecology of the shrimps in coastal lagoon-estuarine systems, with emphasis on the following: the effect of the environment on the shrimps' natural food; techniques for identifi cation of items in shrimps gut contents and stable isotope compositions; consideration of the importance of plants and small animals in the diet; and the effect of mangroves and lagoon-estuarine system on feed ecology. The abundance of penaeid appears to be primarily affected by stochastic variations in environmental factors. However, it has been found that the relationships between macroinfauna, macrofauna and environmental conditions in a tropical estuary may result in more interactions with their predators than a direct response to physical-chemical factors. The combination of the study of shrimps guts contents and stable isotopes shows a composition and seasonal variation in the diets, as well as the source of carbon and nitrogen contained in the shrimp's tissues. In general, the studies suggest that herbaceous detrital inputs to the food web are dominant in supporting shrimps in salt marshes, but phytoplankton or benthic algae may be equally or more important food sources. KEYWORDS:Feeding, gut contents, stable isotopes, shrimps, mangrove, marsh. RESUMENLos camarones son recursos importantes en las lagunas costeras porque utilizan el ecosistema para su desarrollo. Aunque algunos autores clasifi can a los camarones Penaeidae como detritívoros, se encontró que su dieta comprende una gran variedad de ítems. Muchos autores han reportado que los camarones tienen una dieta diversifi cada que incluye varios elementos de la comunidad béntica. Esta revisión describe la ecología alimentaria de los camarones en los sistemas lagunarestuarinos, con énfasis sobre los siguientes aspectos: el efecto del ambiente sobre el alimento natural de los camarones; técnicas para la identifi cación de ítems en los contenidos estomacales de los camarones y la composición de isotopos estables; consideraciones sobre la importancia de las plantas y pequeños animales en la dieta; y el efecto de los manglares y sistema lagunar-estuarino sobre la ecología alimentaria. La abundancia de peneidos parece ser principalmente afectado por variaciones estocásticas en factores ambientales. Sin embargo, se ha encontrado que las relaciones entre macroinfauna, macrofauna y condiciones ambientales en un estuario tropical pueden resultar en más interacciones con sus depredadores que una respuesta directa a factores fi sico-químicos. La combinación del estudio de los contenidos estomacales e isotopos estables muestra la composición y las variaciones estacionales en las dietas, tam...