66 research outputs found

    Determinants of grassland primary production in seasonally-dry silvopastoral systems in Central America

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    Grassland primary productivity is the function that underpins the majority of the fodder production in cattle-rearing silvopastoral farms. Hence, understanding the factors that determine grassland productivity is critical for the design and management of silvpastoral systems. We studied the effect of two factors with documented impact on grassland productivity in seasonally dry silvopastures of Nicaragua, rainfall and trees. We assessed the effects of three species that differed in crown size and phenology, one evergreen, Cassia grandis, and two deciduous species, Guazuma ulmifolia and Tabebuia rosea. Overall, grassland ANPP had a quadratic response to rainfall, with a decline at high rainfall that coincided with peak standing biomass and grassland cover. Trees had a predominately negative effect on grassland productivity, and the effect was concentrated in the rainy season at peak productivity. The effect of the trees corresponded with the tree crown area, but not with crown density. Trees reduced the standing biomass of graminoids and increased forb biomass; thus, the effect of trees on grassland ANPP appears in part to respond to changes in grassland composition. We also found higher levels of soil moisture content below the tree canopy, particularly at the peak of the rainy season when soils tend to become waterlogged. The evergreen species, C. grandis, affected grassland ANPP more strongly than the deciduous specie

    Ecological approaches to human nutrition

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    Malnutrition affects a large number of people throughout the developing world. Approaches to reducing malnutrition rarely focus on ecology and agriculture to simultaneously improve human nutrition and environmental sustainability. However, evidence suggests that interdisciplinary approaches that combine the knowledge bases of these disciplines can serve as a central strategy in alleviating hidden hunger for the world's poorest. To describe the role that ecological knowledge plays in alleviating hidden hunger, considering human nutrition as an overlooked ecosystem service. We review existing literature and propose a framework that expands on earlier work on econutri-tion. We provide novel evidence from case studies con-ducted by the authors in western Kenya and propose a framework for interdisciplinary collaboration to alleviate hidden hunger, increase agricultural productivity, and improve environmental sustainability. Our review supports the concept that an inte-grated approach will impact human nutrition. We pro-vide evidence that increased functional agrobiodiversity can alleviate anemia, and interventions that contribute to environmental sustainability can have both direct and indirect effects on human health and nutritional well-being. Integrated and interdisciplinary approaches are critical to reaching development goals. Ecologists must begin to consider not only how their field can contribute to biodiversity conservation, but also, the relationship between biodiversity and provisioning of nontraditional ecosystem services such as human health. Likewise, nutritionists and agronomists must recognize that many of the solutions to increasing human well-being and health can best be achieved by focusing on a healthy environment and the conservation of ecosystem services

    Quantifying model uncertainty to improve watershed-level ecosystem service quantification: a global sensitivity analysis of the RUSLE

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    Ecosystem service-support tools are commonly used to guide natural resource management. Often, empirically based models are preferred due to low data requirements, simplicity and clarity. Yet, uncertainty produced by local context or parameter estimation remains poorly quantified and documented. We assessed model uncertainty of the Revised Universal Soil Loss Equation – RUSLE developed mainly from US data. RUSLE is the most commonly applied model to assess watershed-level soil loss. We performed a global sensitivity analysis (GSA) on RUSLE with four dissimilar datasets to understand uncertainty and to provide recommendations for data collection and model parameterization. The datasets cover varying spatial levels (plot, watershed and continental) and environmental conditions (temperate and tropical). We found cover management and topography create the most uncertainty regardless of environmental conditions or data parameterization techniques. The importance of other RUSLE factors varies across contexts. We argue that model uncertainty could be reduced through better parameterization of cover management and topography factors while avoiding severe soil losses by targeting soil conservation practices in areas where both factors interact and enhance soil loss. We recommend incorporating GSA to assess empirical models’ uncertainty, to guide model parameterization and to target soil conservation efforts

    Pathways to sustainable land-use and food systems: 2019 Report of the FABLE Consortium

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    This first report by the FABLE Consortium presents preliminary pathways towards sustainable land-use and food systems prepared by the 18 country teams from developed and developing countries, including the European Union. The aim of these pathways is to determine and demonstrate the technical feasibility of making land-use and food systems sustainable in each country. They can also inform mid-century low-emission development strategies under the Paris Agreement on Climate Change. FABLE country teams have aimed for consistency with the SDGs and the Paris Agreement objectives. At this early stage, not all target dimensions have been considered. The report does not discuss policy options for transforming these systems, their implementation, or associated costs and economic benefits. These critical issues will be addressed in the global report by the Food and Land-Use Coalition, which will be published in September 2019 ahead of the Climate Summit convened by UN Secretary-General António Guterres

    Integrating local knowledge and remote sensing for eco-type classification map in the Barotse Floodplain, Zambia

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    This eco-type map presents land units with distinct vegetation and exposure to floods (or droughts) in three villages in the Barotseland, Zambia. The knowledge and eco-types descriptions were collected from participatory mapping and focus group discussions with 77 participants from Mapungu, Lealui, and Nalitoya. We used two Landsat 8 Enhanced Thematic Mapper (TM) images taken in March 24th and July 14th, 2014 (path 175, row 71) to calculate water level and vegetation type which are the two main criteria used by Lozi People for differentiating eco-types. We calculated water levels by using the Water Index (WI) and vegetation type by using the Normalized Difference Vegetation Index (NDVI). We also calculated the Normalized Burn Ratio (NBR) index. We excluded burned areas in 2014 and built areas to reduce classification error. Control points include field data from 99 farmers’ fields, 91 plots of 100 m2 and 65 waypoints randomly selected in a 6 km radius around each village. We also used Google Earth Pro to create control points in areas flooded year-round (e.g., deep waters and large canals), patches of forest and built areas. The eco-type map has a classification accuracy of 81% and a pixel resolution of 30 m. The eco-type map provides a useful resource for agriculture and conservation planning at the landscape level in the Barotse Floodplain

    Assessing ecosystem services from multifunctional trees in pastures using Bayesian belief networks

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    A Bayesian belief network (BBN) was developed to assess preferred combinations of trees in live fences and on pastures in silvopastoral systems. The BBN was created with information from Rivas, Nicaragua, using local farmer knowledge on tree species, trees' costs and benefits, farmers' expressed needs and aspirations, and scientific knowledge regarding tree functional traits and their contribution to ecosystem services and benefits. The model identifies combinations of trees, which provide multiple ecosystem services from pastures, improving their productivity and contribution to farmer livelihoods. We demonstrate how the identification of portfolios of multifunctional trees can satisfy a profile of desired ecosystem services prioritized by the farmer. Diagnostics using Bayesian inference starts with an identification of farmer needs and ‘works backwards’ to identify a silvopastoral system structure. We conclude that Bayesian belief networks are a promising modeling technique for multi-criteria decisions in farm adaptation processes, where interventions must be adapted to specific contexts and farmer preferences

    Big data and multiple methods for mapping small reservoirs: comparing accuracies for applications in agricultural landscapes

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    Whether or not reservoirs contain water throughout the dry season is critical to avoiding late season crop failure in seasonally-arid agricultural landscapes. Locations, volumes, and temporal dynamics, particularly of small (<1 Mm3) reservoirs are poorly documented globally, thus making it difficult to identify geographic and intra-annual gaps in reservoir water availability. Yet, small reservoirs are the most vulnerable to drying out and often service the poorest of farmers. Using the transboundary Volta River Basin (~413,000 sq km) in West Africa as a case study, we present a novel method to map reservoirs and quantify the uncertainty of Landsat derived reservoir area estimates, which can be readily applied anywhere in the globe. We applied our method to compare the accuracy of reservoir areas that are derived from the Global Surface Water Monthly Water History (GSW) dataset to those that are derived when surface water is classified on Landsat 8 OLI imagery using the Normalised Difference Water Index (NDWI), Modified NDWI with band 6 (MNDWI1), and Modified NDWI with band 7 (MNDWI2). We quantified how the areal accuracies of reservoir size estimates vary with the water classification method, reservoir properties, and environmental context, and assessed the options and limitations of using uncertain reservoir area estimates to monitor reservoir dynamics in an agricultural context. Results show that reservoir area estimates that are derived from the GSW data are 19% less accurate for our study site than MNDWI1 derived estimates, for a sample of 272 reservoir extents of 0.09 to 72 ha. The accuracy of Landsat-derived estimates improves with reservoir size and perimeter-area ratio, while accuracy may decline as surface vegetation increases. We show that GSW derived reservoir area estimates can provide an upper limit for current reservoir capacity and seasonal dynamics of larger reservoirs. Data gaps and uncertainties make GSW derived reservoir extents unsuitable for monitoring reservoirs that are smaller than 5.1 ha (holding ~49,759 m3), which constitute 674 (56%) reservoirs in the Volta basin, or monitoring seasonal fluctuations of most small reservoirs, limiting its utility for agricultural planning. This study is one of the first to test the utility and limitations of the newly available GSW dataset and provides guidance on the conditions under which this, and other Landsat-based surface water maps, can be reliably used to monitor reservoir resources

    Collaborative effort to operationalize the gender transformative approach in the Barotse Floodplain

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    Agricultural interventions that aim at alleviating rural poverty have important gender implications. The paper explores a Gender Transformative Approach recognizing that fishing, post- harvest processing, and trading are all gendered activities. On the Barotse Floodplain (Zambia) women are relegated to perform tasks within less profitable nodes of the fish value chain. The assessment of ecosystem services in a select number of Aquatic Agricultural Systems (AAS) focal communities included women’s and men’s perspectives and diverse provisioning, regulating and cultural ecosystem services.Cultivate Africa’s Future Fund (CULTIAF
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