Water management and livelihood choices in southwestern Bangladesh

Coastal Bangladesh faces an increasing number of challenges including cyclones, tidal surges, floods, drought, saline water intrusion, waterlogging and land subsidence, which pose substantial threats to the livelihoods of the coastal inhabitants. In addition to these threats, profound social and land-use changes are complicating the livelihoods of resource users in the region, including the introduction of aquaculture and increasing competition for ground and surface water sources. The government of Bangladesh has targeted this region for investment with irrigation expansion. This paper uses a sustainable livelihood lens to understand the role of investments in water management and irrigation in driving and shaping livelihood changes and transitions over the past ten years and offers recommendations for investments. We find that while water infrastructure development has greatly enhanced the role of agriculture in coastal livelihoods over the last 10 years, further development of irrigation infrastructure should only be prioritized after issues of water governance and inequity across agricultural and aquacultural livelihoods are addressed

Modeling water resources management at the basin level: review and future directions

Water quality / Water resources development / Agricultural production / River basin development / Mathematical models / Simulation models / Water allocation / Policy / Economic aspects / Hydrology / Reservoir operation / Groundwater management / Drainage / Conjunctive use / Surface water / GIS / Decision support systems / Optimization methods / Water supply

Solar or Diesel: A Comparison of Costs for Groundwater‐Fed Irrigation in Sub‐Saharan Africa Under Two Energy Solutions

Sub-Saharan Africa has long been beset with food insecurity and energy poverty. Expanding irrigated agriculture can help boost food production in the region, but this requires energy for accessing water, especially in groundwater-fed irrigation. This paper compared economic performance of groundwater pumping for irrigation under two energy solutions: solar photovoltaic (PV) and diesel fuel. We estimated the life-cycle costs of the power units of two pumping systems for a range of crop and irrigation method scenarios and mapped their relative cost-effectiveness over cropland in sub-Saharan Africa. As a renewable and clean energy source, solar energy has attracted much attention and there is keen interest in investing in solar PV to support the development of irrigated agriculture. Results of this study provide insights into the prospects of promoting solar irrigation in sub-Saharan Africa

Water Resources, Agriculture and Pasture: Implications of Growing Demand and Increasing Scarcity

Key points 1. Water availability for irrigation is threatened in many regions by rapidly increasing demand for nonagricultural water uses in industry, households, and the environment. The scarcity of irrigation water will not only impact crop production, but also meat production, as much of the pasture used to feed livestock is irrigated. 2. Grassland is caught between two countervailing forces: a requirement for increasing meat demand that boosts the need for additional pasture to support livestock production, and rapidly increasing water scarcity that makes pasture irrigation uneconomical. 3. The most effective means of dealing with water scarcity is likely to be conserving water in existing water uses. Improvements in the irrigation sector to increase water use efficiency must be made at the technical, managerial, and institutional levels. 4. Innovative water pricing policies that increase the prices for domestic and industrial water while preserving incomes for farmers and the rural poor will encourage water-saving innovation

Water Resources, Agriculture and Pasture: Implications of Growing Demand and Increasing Scarcity

Water availability for irrigation is threatened in many regions by rapidly increasing demand for nonagricultural water uses in industry, households, and the environment. The scarcity of irrigation water will not only impact crop production, but also meat production, as much of the pasture used to feed livestock is irrigated. Grassland is caught between two countervailing forces: a requirement for increasing meat demand that boosts the need for additional pasture to support livestock production, and rapidly increasing water scarcity that makes pasture irrigation uneconomical. The most effective means of dealing with water scarcity is likely to be conserving water in existing water uses. Improvements in the irrigation sector to increase water use efficiency must be made at the technical, managerial, and institutional levels. Innovative water pricing policies that increase the prices for domestic and industrial water while preserving incomes for farmers and the rural poor will encourage water-saving innovation

Evolutionary trade-offs between testes size and parenting in Neotropical glassfrogs.

In males, large testes size signifies high sperm production and is commonly linked to heightened sperm competition levels. It may also evolve as a response to an elevated risk of sperm depletion due to multiple mating or large clutch sizes. Conversely, weapons, mate or clutch guarding may allow individuals to monopolize mating events and preclude sperm competition, thereby reducing the selection of large testes. Herein, we examined how paternal care, sexual size dimorphism (SSD), weaponry and female fecundity are linked to testes size in glassfrogs. We found that paternal care was associated with a reduction in relative testes size, suggesting an evolutionary trade-off between testes size and parenting. Although females were slightly larger than males and species with paternal care tended to have larger clutches, there was no significant relationship between SSD, clutch size and relative testes size. These findings suggest that the evolution of testes size in glassfrogs is influenced by sperm competition risk, rather than sperm depletion risk. We infer that clutch guarding precludes the risk of fertilization by other males and consequently diminishes selective pressure for larger testes. Our study highlights the prominent role of paternal care in the evolution of testes size in species with external fertilization

Contrasting parental roles shape sex differences in poison frog space use but not navigational performance.

Sex differences in vertebrate spatial abilities are typically interpreted under the adaptive specialization hypothesis, which posits that male reproductive success is linked to larger home ranges and better navigational skills. The androgen spillover hypothesis counters that enhanced male spatial performance may be a byproduct of higher androgen levels. Animal groups that include species where females are expected to outperform males based on life-history traits are key for disentangling these hypotheses. We investigated the association between sex differences in reproductive strategies, spatial behavior, and androgen levels in three species of poison frogs. We tracked individuals in natural environments to show that contrasting parental sex roles shape sex differences in space use, where the sex performing parental duties shows wider-ranging movements. We then translocated frogs from their home areas to test their navigational performance and found that the caring sex outperformed the non-caring sex only in one out of three species. In addition, males across species displayed more explorative behavior than females and androgen levels correlated with explorative behavior and homing accuracy. Overall, we reveal that poison frog reproductive strategies shape movement patterns but not necessarily navigational performance. Together this work suggests that prevailing adaptive hypotheses provide an incomplete explanation of sex differences in spatial abilities

Sustainable and Equitable Growth in Farmer-led Irrigation in Sub-Saharan Africa: What Will it Take?

The rapid development of farmer-led irrigation is increasing agricultural productivity, incomes, employment and nutrition, but it might well not achieve its full potential. Small-scale irrigators tend to be younger, male and better-off. Women and resource-poor farmers – the majority of farmers in sub-Saharan Africa – are disadvantaged and often excluded from the numerous benefits to be gained from irrigation. Equity in access to water management technologies and practices is constrained by numerous factors, including high investment costs, absence of financial services, poor market integration, inadequate information services, and labour constraints. Lack of institutions for collective management of natural resources, such as water, further restricts access for resource-poor farmers, increasing inequity. In the absence of sustainable natural resources management approaches to agricultural intensification, this situation may become more acute as natural resources become increasingly valuable, and therefore contested. Realising the full potential of farmer-led irrigation requires contextualised policies, institutions and practices to improve equity, markets and sustainability and help ensure that sector growth is inclusive and beneficial