No abstract

Mangroves occur in coastal areas and are therefore vulnerable to anthropogenic disturbance and exhibit high rates of deforestation. Mexico is among the countries with the highest degree of mangrove deforestation in America; however, precise data on national mangrove coverage in Mexico is incomplete, making it impossible to accurately ascertain the rate of mangrove loss over time. Precise information is necessary to assess changes at local and regional scales to detect the magnitude, trends, and drivers of the transformation. This study aimed to estimate the loss of mangrove cover in the area of Mahahual-Xcalak (Quintana Roo, Mexico) between 1995 and 2007, to calculate the annual deforestation rate and to identify the drivers of deforestation. Landsat TM and ETM+ images from 1995 and 2007 were used to estimate the loss of mangrove cover using a multitemporal analysis. Semi-structured interviews with local residents of Mahahual and Xcalak were undertaken to identify and validate the drivers of deforestation. The image analysis for the 12-year period showed that 1070 ha of mangrove forest have been lost, with an annual deforestation rate of 0.85%—a relatively high value compared with other mangrove regions in Mexico. The main factor that has triggered the reduction of mangrove coverage is the expansion of anthropogenic land uses (e.g., settlements and roads). This study concludes that conservation and rehabilitation programs need to be implemented so that the Mahahual-Xcalak mangrove environment can continue to provide key ecosystem services.

La cría de la abeja sin aguijón ko’olel kaab (Melipona beecheii) es una actividad ancestral en vía de desaparición en la reserva Los Petenes. Por su importancia en la estrategia familiar en el área natural protegida y la conservación de la diversidad de especies de abejas nativas, se planteó el estudio de la situación y perspectivas de la meliponicultura en dicha área. Se usaron encuestas semiestructuradas, entrevistas con informantes clave y observación participante. Los resultados muestran que solo seis comunidades de las 17 manejan la abeja ko’olel kaab, los meliponicultores están constituidos mayoritariamente por hombres de edad avanzada con débil organización social. La perspectiva de la meliponicultura es alentadora porque se ubica en un área natural protegida y, el conocimiento y manejo tradicional aún persiste y la realizan familias mayas para uso medicinal y ceremonial. El mercado y el valor cultural de la meliponicultura son factores que pueden contribuir a su rescate.

No abstract

The effects of intensive banana production with high mineral-fertilizer application and of extensive pastures were compared regarding water quality in a lowland region of SE Mexico. We monitored NO À 3 , NO À 2 , and PO 4 3-concentrations in groundwater (80 m depth), subsurface water (5 m depth), and surface water (open-ditch drainage) at monthly intervals for a one-year period. Irrespective of the land use, the NO À 3 concentrations in all water bodies were lower than the threshold value for drinking water and aquatic life. Particularly in areas with intense banana production, the NO À 2 contents in water exceeded the safety thresholds for drinking water of 1.0 mg L -1 (WHO, 2006) and aquatic ecosystems of 0.2 mg L -1 (OATA, 2008). Water from pastureland showed significantly higher PO 4 3-concentration than that from the banana plantation, indicating a high risk of eutrophication. There is a need to provide recommendations for optimal time and amount of N application in commercial banana production and for limitation of P inputs in pasturelands to avoid further contamination of water bodies.