Vulnerability of the agricultural sector to climate change: The development of a pantropical Climate Risk Vulnerability Assessment to inform sub-national decision making

As climate change continues to exert increasing pressure upon the livelihoods and agricultural sector of many developing and developed nations, a need exists to understand and prioritise at the sub national scale which areas and communities are most vulnerable. The purpose of this study is to develop a robust, rigorous and replicable methodology that is flexible to data limitations and spatially prioritizes the vulnerability of agriculture and rural livelihoods to climate change. We have applied the methodology in Vietnam, Uganda and Nicaragua, three contrasting developing countries that are particularly threatened by climate change. We conceptualize vulnerability to climate change following the widely adopted combination of sensitivity, exposure and adaptive capacity. We used Ecocrop and Maxent ecological models under a high emission climate scenario to assess the sensitivity of the main food security and cash crops to climate change. Using a participatory approach, we identified exposure to natural hazards and the main indicators of adaptive capacity, which were modelled and analysed using geographic information systems. We finally combined the components of vulnerability using equal-weighting to produce a crop specific vulnerability index and a final accumulative score. We have mapped the hotspots of climate change vulnerability and identified the underlying driving indicators. For example, in Vietnam we found the Mekong delta to be one of the vulnerable regions due to a decline in the climatic suitability of rice and maize, combined with high exposure to flooding, sea level rise and drought. However, the region is marked by a relatively high adaptive capacity due to developed infrastructure and comparatively high levels of education. The approach and information derived from the study informs public climate change policies and actions, as vulnerability assessments are the bases of any National Adaptation Plans (NAP), National Determined Contributions (NDC) and for accessing climate finance

Proceedings of the International Workshop on: methods and tools for water-related adaptation to climate change and climate proofing

The workshop fits in the National Water Plan of the Netherlands’ government of which the international chapter includes the strengthening of cooperation with other delta countries, including Indonesia, Vietnam and Bangladesh and is part of the work plan of the Cooperative Programme on Water and Climate, a Netherlands’ sponsored programme with the objective to improve knowledge and capacity on the relation between water and climate change especially in developing countries and countries in transition

Spatial modelling and GIS-based decision support tools to evaluate the suitability of sustainable aquaculture development in large catchments

Land, water and natural resources are under increasing pressure due to rising demands for food and energy from the rapidly growing global population. Across a catchment there can be multiple stakeholders with conflicting opinions over how space and resources should be used and managed. Consequently, it is important to consider the suitability of a catchment for a particular purpose to optimise use of the area and minimise potential conflicts and impacts on the wider environment. Aquaculture is a significant contributor to world food supply and as fisheries are unlikely to increase it is expected that the industry will continue to grow and expand in the future to help meet food security requirements. As a result, it is essential that the sector aims for sustainable development within the most suitable locations. However, it can be difficult to assess the suitability of multiple large catchments and some issues may not be immediately apparent. This project aimed to show how spatial models could be used as decision support tools to evaluate the suitability of large catchments for sustainable aquaculture. Four large areas of importance to aquaculture were selected; covering 10,148km2, 26,225km2, 48,319km2 and 66,283km2 in Bangladesh, China, Thailand and Vietnam respectively. Asia is by far the most dominant aquaculture region in the world and each of the four study areas contribute to local, regional and global food supplies. The study area in Bangladesh was located in Khulna region in the south west of the country and the main species of focus were prawn and shrimp. The Chinese study area was located in the south eastern province of Guangdong and the main species covered were tilapia and shrimp. Similarly, in Thailand, the main species evaluated were tilapia and shrimp whilst the study area extended across the Central region. Finally, the largest study area was the Mekong Delta in Vietnam and the main species of focus in this area were pangasius catfish and shrimp. One of the challenges in modelling large catchments is model applicability and data availability. Often, the required data are not available (or accessible) and it would be difficult, time consuming and expensive to collect new information. Furthermore, when assessing multiple areas is it vital that a representative and unbiased approach is used where no one catchment is favoured over the other due to higher quality data. Therefore, this study used data that are available for almost any area in the world; allowing future application of the models and enabling effective and unbiased decision support. Four modelling stages were employed in this study to evaluate the suitability of large catchments for sustainable aquaculture development. The first stage was the classification of seasonal land use models from satellite imagery. This provides information on what the land is used for and how aquaculture could impact or be impacted by the wider environment. The second step was the development of seasonal models of site suitability using optimal values within a GIS-based multi-stage framework. These models identify which locations are best for culture and can also be used to estimate the availability of areas for food production. The next stage investigated the use of Maxent as a novel approach in site suitability modelling to evaluate the conditions experienced by existing farms. The information from Maxent can be used to identify trends, opportunities and concerns related to sustainable management and farm locations. Finally, qualitative models of non-point source pollution (NPSP) were developed which assess the risk of NPSP within a catchment. NPSP is an issue which can impact both aquaculture and the wider environment. Thus, it is important to understand the areas within a catchment where NPSP risk is higher enabling the establishment of monitoring and/or mitigation procedures. The models support the ecosystem approach to aquaculture (EAA) and enable objective planning and management strategies to enhance productivity across large catchments without negatively impacting the environment. In order to meet growing food requirements, large areas will need to be used for agriculture and aquaculture; therefore, analysis at a wider catchment level, which complements assessment at a local scale, is required as it allows a holistic view of the situation. The work presented here illustrates the potential use of spatial models across large catchments and considers the suitability of the areas for aquaculture development

Comparative assessment of the vulnerability and resilience of 10 deltas : work document

Background information about: Nile delta (Egypt), Incomati delta (Mozambique), Ganges-Brahmaputra-Meghna (Bangladesh), Yangtze (China), Ciliwung (Indonesia), Mekong (Vietnam), Rhine-Meuse (The Netherlands), Danube (Romania), California Bay-Delta, Mississippi River Delta (USA

GIS-based modelling of agrochemical use, distribution and accumulation in the Lower Mekong Delta, Vietnam: A case study of the risk to aquaculture

In recent years, the Mekong delta has been strongly developed both for agriculture and aquaculture. However, there is scope for a negative impact of agriculture on aquaculture in term of production and quality of seafood products. Specifically, the large amount of pesticides imported and used in the Mekong delta not only help agriculture purposes but can also easily enter aquatic systems and affect aquaculture. Pesticides can be transported in the environment by chemo-dynamic procedures and hydrological processes. As a result, pesticides used in agriculture become dispersed and their residues in sediment, water and biota have been detected in the Mekong delta. This study investigated the overall pesticide process including pesticide use, modelling pesticide accumulation and evaluating the potential impact on aquaculture sites for some target aquatic species. The risk of pesticides use in the Mekong delta was addressed in three stages: (1) investigating current pesticide use status in the Mekong delta; (2) modelling pesticide loss and accumulation; (3) classifying pesticide risk areas for aquaculture of target cultured species. A survey of 334 farms covering a total area of ~20,000km2 in the Mekong delta took place between 2008 and 2009. Information on pesticide types and quantities was recorded using questionnaires, and it was found that 96 pesticides in 23 groups were popularly used for agricultural purposes. Dicarboximide, Carbamate and Conazole had the highest use at ~3000, ~2000 and ~2000 g/ha/year respectively. The survey revealed an increase in pesticide use per hectare since previous surveys in the Mekong delta in 1994, 2000, and 2004. However, the highly persistent compounds (WHO classification classes II, III and IV) appeared to have reduced in use. Insecticides previously represented >50% of the total pesticides used, however, the resent survey has shown their use has decreased to ~38%.There was a parallel increase in use of fungicides from previous levels of <30% of total pesticides to more recently ~41%. The combination of pesticide information and geo-location data enabled display and analysis of this data spatially using a Geographic Information System (GIS). A pesticide loss and accumulation model was established through combination of several sub-models including sediment loss and accumulation, direct loss, and water runoff, all of which were implemented and integrated within the GIS environment. MUSLE (Modified Universal Soil Loss Equation) was used to estimate sediment loss and accumulation in the Mekong delta and the Curve Number method (CN Method) was applied to predict water runoff and discharges and flow accumulation. Modelling commenced from the first pesticide application in April, based on 4 day time-steps. All mathematical calculations run within each time step automatically reiterated in the following time step with the new input datasets. The results from fuzzy classification of the pesticide model outcomes were considered in terms of the 96hr lethal concentration (LC50) in order to classify the risk and non-risk areas for catfish and tiger shrimp culture. The sediment loss and accumulation model shows that the highest loss of sediment was in the rainy season, especially in May to October. Vegetables and short term crop areas were found be most strongly eroded. The MUSLE model showed that the highest sediment accumulation was in the hilly areas (~1066.42 tonne/ha/year); lower in riverside areas (~230.39 tonne/ha/year) and lowest in flooded paddy areas (~150.15tonne/ha/year). Abamectin was used as an example throughout this study to estimate pesticide loss and its effects on aquaculture. The results showed that pesticide loss by runoff and sediment loss is less than the loss by half-life degradation (for Abamectin specifically). Accumulation of Abamectin occurred at highest rate in May and October and decreased with time. The spatial models showed that pesticide residues concentrated in the river and riverside areas. In order to evaluate the acute toxicity impacts, three levels of water depth in ponds were modelled as culture depths for catfish and tiger shrimp. The results show that the highest risk areas for catfish occurred in May and October with ~333,000 and ~420,000 ha at a pond depth of 0.5 m; ~136,000 and ~183,000 ha at a pond depth of 1.0 m; and ~10,840 and ~19,000 ha at a pond depth of 1.5 m. Risk areas for catfish mainly concentrated at the riverside and in part of the coastal areas. For tiger shrimp, the risk periods during the year were similar to those found for catfish. The highest risk areas for shrimp were ~648,000 and ~771,000 ha at 0.5 m pond depth; ~346,000 and ~446,700 ha at 1.0 m pond depth; and ~185,000 and ~250,000 ha at 1.5 m pond depth. Overall, deeper ponds reduced the risk. This study has developed a method to evaluate the negative impact of input pesticides to the environment from agricultural use related to fluctuation of aquaculture risk areas. The research indicates the potential relationship between pesticide input and the risk areas for aquaculture. The model has several significant uses: 1) it can provide information to policy makers for a more harmonized development of both aquaculture and agriculture in the Mekong delta in the future, 2) it provides data for aquaculture investment analysis to decrease the hazards caused by pesticide impacts, and 3) it provides a model capable of application to wide field scenarios and suitable for any pesticide type

Investigation of a novel approach for aquaculture site selection

This study investigated the potential use of two &ldquo;species distribution models&rdquo; (SDMs), Mahalanobis Typicality and Maxent, for aquaculture site selection. SDMs are used in ecological studies to predict the spatial distribution of species based on analysis of conditions at locations of known presence or absence. Here the input points are aquaculture sites, rather than species occurrence, thus the models evaluate the parameters at the sites and identify similar areas across the rest of the study area. This is a novel approach that avoids the need for data reclassification and weighting which can be a source of conflict and uncertainty within the commonly used multi-criteria evaluation (MCE) technique. Using pangasius culture in the Mekong Delta, Vietnam, as a case study, Mahalanobis Typicality and Maxent SDMs were evaluated against two models developed using the MCE approach. Mahalanobis Typicality and Maxent assess suitability based on similarity to existing farms, while the MCE approach assesses suitability using optimal values for culture. Mahalanobis Typicality considers the variables to have equal importance whereas Maxent analyses the variables to determine those which influence the distribution of the input data. All of the models indicate there are suitable areas for culture along the two main channels of the Mekong River which are currently used to farm pangasius and also inland in the north and east of the study area. The results show the Mahalanobis Typicality model had more high scoring areas and greater overall similarity than Maxent to the MCE outputs, suggesting, for this case study, it was the most appropriate SDM for aquaculture site selection. With suitable input data, a combined SDM and MCE model would overcome limitations of the individual approaches, allowing more robust planning and management decisions for aquaculture, other stakeholders and the environment

Aquaculture Asia, Vol.13, No.2, pp.1-56, April-June 2008

Peter Edwards writes on rural aquaculture: From integrated carp polyculture to intensive monoculture in the Pearl River Delta, South China. Better management practices for Vietnamese catfish. Ipomoea aquatica – an aquaculture friendly macrophyte. A status overview of fisheries and aquaculture development in Pakistan with context to other Asian countries. The changing face of post-grad education in aquaculture: contributing to soaring production and sustainable practices. Hatchery management in Bangladesh. Production of Cirrhinus molitorella and Labeo chrysophekadion for culture based fisheries development in Lao PDR Part I: Captive spawning. Application of ipil-ipil leaf meal as feed Ingredient for monosex tilapia fry (Oreochromis niloticus) in terms of growth and economics. Fermented feed ingredients as fish meal replacer in aquafeed production Aquaculture and fishing management in coastal zone demarcation: the case of Thailand. Reservoir fisheries of freshwater prawn – success story of an emerging culture-based giant freshwater prawn fishery at Malampuzha Dam in Kerala, India. Determining and locating sea cage production area for sustainable tropical aquaculture. SPC Pacific-Asia marine fish mariculture technical workshop: “Farming Marine Fishes for our Future”. Developing Better Management Practices for Marine Finfish Aquaculture. Breeding and seed production of silver pompano (Trachinotus blochii, Lacepede) at the Mariculture Development Center of Batam. Potential of silver pomfret (Pampus argenteus) as a new candidate species for aquaculture. NACA Newsletter

Water Figures Asia: news of IWMI’s work in Asia

Water policy, Water pollution, Land degradation, Land use, Asia, Vietnam

Coastal vulnerability assessment: a case study in Kien Giang, western part of the Mekong River Delta in Vietnam

Climate change, particularly sea-level rise, threatens low-lying coastal systems, such as small islands on coral atolls, and deltas where millions of people are living. The Mekong River Delta is considered especially at risk. Although most of the delta is only a few metres above sea level, there have been few assessments of vulnerability at local scale. The aim of this thesis is to provide quantitative and qualitative information to guide the process of adaptation and provide visualisations that will enhance local authority’s decision making to adapt to climate change, particularly sea-level rise. It focuses on the seven coastal districts within Kien Giang province in the western, micro-tidal section of the delta. A framework is adopted that integrates biophysical effects and socioeconomic stressors for the case study area and consists of three main components of vulnerability: exposure, sensitivity, and adaptive capacity. The analytical hierarchical process (AHP) method of multi-criteria decision making was integrated directly into a geographic information system (GIS) to derive a composite vulnerability index that indicated areas or hotspots most likely to be vulnerable to sea-level rise. The hierarchical structure comprised three components: exposure, sensitivity and adaptive capacity (level 1); and eight sub-components (level 2): seawater incursion, flood risk, shoreline change, population characteristics, landuse, as well as socioeconomic, infrastructure, and technological capability. The Digital Shoreline Analysis System (DSAS) tool was used to calculate rates of shoreline change along the Kien Giang coast over time in order to derive the shoreline change sub-component that contributed to the exposure component. Beyond this, a further 22 variables (level 3) and 24 sub-variables (level 4) related to vulnerability were also mapped. Based on the weights of variables derived from AHP pair-wise comparisons, a final map was generated to visualise areas reported into five categories of relative vulnerability; very low, low, moderate, high to very high vulnerability. Several regional patterns emerged. Relatively high exposure to seawater incursion, flood risk, and moderate loss of mangroves characterised the coastal fringe of each district. Those areas found to be most sensitive tended to have moderate population density, generally with a large rural population and high proportions of ethnic households with limited availability of agricultural land. Many aspects of adaptive capacity could only be represented at district scale, with the least adaptable areas consisting of large proportions of poor households, low income, and moderate densities of transport, irrigation, and drainage systems. Finally, most coastal districts were determined to be of moderate to relatively high vulnerability, with scattered hotspots along the Kien Giang coast, which coincided with settlement areas. The results obtained, enable identification and prioritisation of the areas, or hotspots most likely to be vulnerable, for which site-specific assessments might further assist the local authorities and communities in better coastal management and conservation. However, the limitations of data accessible at an entire district can influence the outcome. Social vulnerability remains a challenge because it is changing over time and space