Lake drying and livelihood dynamics in Lake Chad: unravelling the mechanisms, contexts and responses

This article examines lake drying and livelihood dynamics in the context of multiple stressors through a case study of the ‘‘Small Lake Chad’’ in the Republic of Chad. Livelihoods research in regions experiencing persistent lake water fluctuations has largely focused on the wellbeing and security of lakeshore dwellers. Little is known about the mechanisms through which lake drying shapes livelihood drawbacks and opportunities, and whether locally evolved responses are enhancing livelihoods. Here we address these gaps using empirical, mixed-methods field research couched within the framework of livelihoods and human well-being contexts. The analysis demonstrates that limited opportunities outside agriculture, the influx of mixed ethnic migrants and the increasing spate of violence all enhance livelihood challenges. Livelihood opportunities centre on the renewal effects of seasonal flood pulses on lake waters and the learning opportunities triggered by past droughts. Although drying has spurred new adaptive behaviours predicated on seasonality, traditional predictive factors and the availability of assets, responses have remained largely reactive. The article points to where lake drying fits amongst changes in the wider socioeconomic landscape in which people live, and suggests that awareness of the particularities of the mechanisms that connect lake drying to livelihoods can offer insights into the ways local people might be assisted by governments and development actors

La naturaleza en contexto : hacia una ecología política mexicana

El texto recorre los orígenes de la ecología política en el nivel internacional e identifica sus etapas y temas centrales, para después evaluar su desarrollo en México. Los nueve estudios de caso que conforman la publicación, elaborados por especialistas reconocidos de instituciones nacionales, abarcan temas diversos como los conflictos ambientales, la agrotecnología, la conservación en áreas protegidas, los movimientos sociales y la restauración de ecosistemas, analizando la forma en que las dinámicas sociopolíticas se entretejen con los procesos de degradación ambiental y determinan los resultados de las políticas públicas y los esfuerzos de conservación. A lo largo de sus nueve capítulos, el libro recorre los diferentes enfoques y temas que hacen hoy de la ecología política una disciplina de gran vitalidad y enorme potencial para comprender la realidad ambiental mexicana

The complexities of measuring fine sediment accumulation within gravel-bed rivers

Fine sediment storage within gravel beds is a key component of catchment sediment budgets and affects the health of benthic and hyporheic habitats. Here, we assess the performance of two substrate infiltration traps for the characterization of fine sediment (<2 mm) accumulation. One design, the vertically extending sediment trap, permits both lateral and vertical exchange in the sediment column, whereas the second type, a more traditional fixed‐area sediment trap with impermeable side walls, permits only vertical exchange. Traps were deployed at three sites on the River Tame, Birmingham (UK), over varying installation periods (14–401 days). Results indicate that the facilitation of multiple pathways of exchange within the vertically extending sediment traps (vertical and lateral) resulted in a significantly greater amount of fine sediment being accumulated than in adjacent fixed‐area sediment traps. This suggests that lateral transport is an important component contributing to fine sediment accumulation. However, there are notable and inherent problems associated with the use of different types of sediment trap and in the way the data should be presented and interpreted. This paper discusses the practical implications of the study findings and reflects on the complexities of undertaking accurate sediment deposition measurements in the field