Patrones de uso de la tierra en la Amazonía central ecuatoriana: Una comparación entre etnias Kichwa, Shuar y colonos

This paper analyzes the land use patterns of mestizo-colonists and indigenous populations in the Ecuadorian Amazon. With data from a household survey conducted in colonist, Kichwa and Shuar communities in the Pastaza province, Ecuador, we determined that, as expected, colonists mostly engage in commercial agriculture and cattle ranching. There are substantial differences in land use patterns of both indigenous groups under study. Like colonists, the Shuar engage in produce cash crops and cattle, whereas the Kichwa almost exclusively engage in subsistence farming. Such different patterns appear to be related to local conditions, migratory and settlement patterns and the degree of exposure to the market economy. Beyond this, the results presented here indicate that, contrary to the general wisdom, the livelihood strategies and land use patterns of indigenous peoples do not necessarily differ from those adopted by indigenous peoples.Este artículo analiza los patrones de uso de la tierra de poblaciones colono-mestizas e indígenas (Kichwa y Shuar) en la Amazonía ecuatoriana. Con datos de una encuesta de hogar realizada en comunidades colonas, Kichwa y Shuar de la provincia de Pastaza, Ecuador, se determinó que los colonos se dedican principalmente a la agricultura comercial y a la ganadería extensiva. Por otra parte, existen diferencias marcadas en los patrones de uso de la tierra de las dos etnias indígenas estudiadas. Como los colonos, los Shuar se dedican a la producción de cultivos comerciales y la crianza de ganado vacuno, en tanto que los Kichwa se dedican casi exclusivamente a la agricultura de subsistencia. Estas diferencias parecen estar relacionadas con las condiciones locales, trayectorias de migración y asentamiento y el grado de integración a la economía de mercado. Más allá de esto, los resultados de este estudio indican que, contrariamente a la creencia general, las estrategias de supervivencia y los patrones de uso de la tierra de los colonos no necesariamente ni en todos los casos difieren de aquellas adoptadas por las poblaciones indígenas

Laboratory assays with non-forced exposure to predict the preferential spatial distribution of fish in two ecuadorian rivers

Trabajo presentado en la SETAC Europe 27th Annual Meeting (Environmental Quality Through Transdisciplinary Collaboration), celebrada en Bruselas del 7 al 11 de mayo de 2017.Laboratory aquatic ecotoxicity assays used to provide data for ecological risk assessments assume that, under natural conditions, organisms living in a contaminated habitat are mandatorily and continuously exposed to contaminants. This assumption neglects the ability of the organisms to detect and avoid contamination moving towards less disturbed habitats such as expected in fluvial systems. Along a river, contaminants can be dispersed forming a gradient or even be patchy distributed, conditioning the habitat selection process by organisms as well as their avoidance and preference behavior. Therefore, in the present study, we assessed the avoidance and preference responses of the model fish Danio rerio when exposed to water samples from two Ecuadorian rivers (Pescadillo River and Oro River) with different disturbance levels. A non-forced exposure system, in which water samples from different river points are simultaneously assayed, allowing organisms to move freely between river samples and select the most favorable sample, was used. Results showed that organisms presented a trend to avoid Pescadillo River upstream samples, moving downstream towards to the confluence zone with Oro River. On the other hand, fish exposed to Oro River samples preferred moving upstream. When exposed to samples from both rivers simultaneously, fish tended to prefer Oro River samples. These results leaded us to predict that, as both rivers are connected, fish avoiding environmental disturbers in Pescadillo River would move to Oro River. Therefore, effects of potential stressful conditions present in Pescadillo River that trigger avoidance response by fish may depress fish populations in that river and, indirectly, affect Oro River by inducing an unexpected fish immigration.N