Dynamics of livelihoods and resource use strategies in different ecosystems of the coastal zones of Bac Lieu Province, Vietnam.

Abstract

Abstract The coastal areas in Bac Lieu Province of the Mekong Delta have undergone rapid changes in environmental and socio-economic conditions since the early 1990s when a saltwater control project was established to promote food crop production in the traditional rice-saltwater-based farming areas. A series of coastal embankments and tidal sluices was constructed gradually to control saltwater intrusion, which was used subsequently to regulate fresh and salt water in order to facilitate saltwater aquaculture. Household land and water use have evolved with the levels and intensity of these water management interventions. This study uses the Sustainable Livelihoods Framework to assess the resource base at the household level and the livelihoods strategies and outcomes for six villages representative of the four different ecosystems in Bac Lieu Province. The ecosystems were distinguished by the scale and timeframe of the water management intervention. The 'early intervention zone' is characterized by alluvial soil types, with the water and environment having been changed from a brackish to a freshwater ecology prior to 1998, providing stability after the transition had been completed. The 'recent intervention zone' has large areas of acid sulfate soils, with the water and environment having been changed to a freshwater ecology after 1998. However, since 2002 most areas of this zone have been converted back to a brackishwater system. The 'marginal intervention zone' is not affected much by the closure of sluices. The 'no intervention zone' located to the south of the embankment has not been affected by the sluice system and was under salt water throughout the survey period. A panel data set generated from household surveys conducted on the selected hamlets in all the intervention zones was used for this study. A baseline survey was first conducted in 2000 and repeat surveys of the sample households were conducted in 2003 and 2007, including the households of the baseline survey plus an additional sample to assess changes in land use and livelihood systems. A data set from household surveys conducted in the control zone - no water management intervention - in 2003 and 2007 was used for comparative analysis. The study noted that the dynamics of livelihoods resulted from changes in resource use and productivity. Land use intensity by double and triple cropping and productivity of rice had increased in the early intervention zone, where freshwater and soil conditions prevailed. Variation among paddy yields was reduced gradually. Shifting from rice-shrimp to shrimp and back to rice-shrimp systems was observed in the marginal intervention zone, where less variability of shrimp farming was also noted. Extensive shrimp culture under rice-shrimp systems had much higher benefit-cost ratios compared with mono shrimp culture in the recent and no intervention zones. The most drastic changes in land use and also in the livelihood outcomes were observed in the recent intervention zones in the period of analysis. As a result of the saltwater control regimes, farming systems in this zone shifted from saltwater based on rice-aquaculture systems to intensive rice, and then shifted to saltwater shrimp farming. High variability in the profitability of shrimp and, as a result, in livelihoods was also noted in this zone.