Impact of saltwater intrusion on relation to fruit growing households in Ben Tre, Vietnam

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Can Tho university Vietnam

Impact of saltwater intrusion on relation to fruit growing households in Ben Tre, Vietnam

Abstract

Methodology / approach. This study used the United Nations' Livelihood Vulnerability Index (LVI) and a similar index from the Intergovernmental Panel on Climate Change (LVI-IPCC) using data from 196 interviewed mangosteen growers in Cho Lach district, Ben Tre province in 2016 and 2018. A total of twenty-five (25) indicators are applied to calculate the two indices, using data as exposure to saltwater intrusion and natural hazards (5), socio-demographic factors (11), and sensitivity of health, finance, and source of water for domestic use (9).

Originality / scientific novelty. The study provides a set of indicators to assess the vulnerability of this low-vulnerable area based on past studies as well as the actual situation of the study area in 2016 and 2018 to determine what factors influenced the main components, LVI and LVI - IPCC. These indicators represented the characteristics of the rural households in Vietnam and other Asian countries. This research also indicated how LVI and LVI - IPCC results differently and when they should be used. The analysis identified the factors influencing the LVI and LVI - IPCC by levels of saltwater intrusion in different years of 2016 and 2018, two different severe and less severe sites, adaptive and non-adaptive households, and their interaction.

Practical value / implications. LVI and LVI-IPCC are good indicators for local and regional assessments on how saltwater intrusion and natural hazards affect households' and communities' livelihood and thereby how to guide them to respond promptly in such cases.

Main part

mangosteen province vietnamese vulnerability

Introduction and review of literature. Saltwater intrusion has dramatically affected the Mekong Delta of Vietnam in recent years, especially the whole Ben Tre province, one of the coastal areas in this region in 2016 [1; 2; 3; 4]. Saltwater intrusion in 2016 in Ben Tre province attacked seriously the areas that both regularly and rarely confront saltwater intrusion annually. Due to the rapid and abnormal sea level rise in the Mekong Delta during the dry season of 2016, residents in Ben Tre province were not warned of the occurrence of saltwater intrusion until it was too late. Almost all the cultivation areas were seriously damaged this year and the year after in Ben Tre.

Cho Lach is an inland district in Ben Tre province known for its tropical fruit trees, particularly mangosteen (Garcinia mangostana), which is grown in the Mekong Delta and Ben Tre province. Mangosteen growers cut mangosteen trees to move to other crops, mainly planting fruit seedlings to serve Ben Tre province and surrounding provinces, resulting in a major reduction in the area of mangosteen trees in 2017-2018. Furthermore, the return on mangosteen was lower than that of other fruits such as durian, pomelo, and seedlings because mangosteen trees need 8 years to bear fruit and 12-15 years to have a good yield.

The Livelihood Vulnerability Index (LVI) was used to quantify farming households' vulnerability to climate change and variability. Vulnerability to climate change is defined by the IPCC [5] as the degree to which a system is susceptible to, or incapable of, enduring detrimental consequences of climatic change and variability [6]. Vulnerability, according to the IPCC, is a set of functions that includes potential impacts and adaptive capacity. Exposure to vulnerable populations and social sensitivity, dependence on vulnerable resources, and comprehension of resource conditions, are all possible consequences. Livelihood vulnerability can be assessed at the individual, household, and community levels [2; 7; 8; 9; 10].

The next section explains how the sub-components of livelihood vulnerability are assessed and chosen. Exposure to natural hazards or climate change are important factors affecting livelihoods, especially for households or communities heavily dependent on agricultural production or vulnerable [8; 11; 12; 13]. Many studies use livelihood vulnerability index to assess the impact of climate change, flooding, saltwater intrusion, and land and water changes on livelihood and related vulnerable factors [4; 14; 15]. The exposure of climate change can be measured by the duration of drought, saltwater intrusion, change in rainfall or temperature while changes in soil and water quality and quantity supply for irrigation [2; 16; 17; 18]. In this study, this major component is separated into two sub-components, namely the exposure to saltwater intrusion and natural hazards. The natural hazards included changes in weather or rainfall affecting fruit setting and yield of mangosteen. Besides, mangosteen growers were facing unfavorable conditions in soil quality and irrigation water supply. These were the common constraints that the mangosteen growers confronted. It is noted that saltwater intrusion was not common problem in this study site; thus, the change in saltwater intrusion in 2016 and 2018 will be a good example to see how saltwater intrusion affects their livelihood and income.

In terms of adaptive capacity, the first sub-components mostly used are the socio-demographic profile, human capital or resources of the households [8; 19]. The factors of these sub-components usually show the vulnerability of the household heads, who have the most important decisions for the households and their livelihood strategies [2; 11; 20]. In developing countries, agricultural-based households with female-head are often more vulnerable because these families often lack men, who do most of the main labor. The educational attainment and age of the household heads would have a significant impact on their decision on livelihood strategies [7]. The vulnerability to the households' labor force is the proportion of dependents, who are under 15 years old and over 65 years old. The high dependency rate has a direct impact on livelihood strategies, household income, and expenditure [12; 21].

The second sub-components of adaptive capacity are indicators that demonstrate their reliance on agriculture or income sources that are highly vulnerable to climate and natural-environment change [1]. Households with high percentages of income from agriculture are more vulnerable when they increase their exposure to climate change or natural hazards [2; 4]. The high income diversification index, or the number of activities that generate household income, reduces the risk of dependence on only one source of income, especially on agricultural or cultivation income [4]. However, the temporary or long-term migration of the main labor force to seek non - agricultural income helps households have more income, but it also places a burden on the household's remaining labor [8; 20]. Land for production is an important resource of the household that affects the household's livelihood strategy. A large land area helps agricultural production households generate more income [1]. However, households with less land often look for non-farm activities to earn extra income. The high diversification index, especially with non-farm activities, shows that these households are vulnerable [2; 8]. The poverty rate or per capita income is an important criterion that influences livelihood strategies [8].

The third sub-component of adaptive capacity is social networks. These factors represent the social capital of the household [22; 23]. When one household is able to solve problems by themselves instead of relying on external support, it reflects their capacity to cope with difficulties. However, because of a lack of outside communication from relatives, neighbors, and local authorities, it would limit the opportunity to update information, particularly for households that may be slow to receive warning alerts to saltwater intrusion or sudden changes in weather or market prices [24]. Households with relatives involved in or participating in civil organizations would help them update good information or have better opportunities to access external support [22; 23].

Sensitivity is an indicator that reflects households' social vulnerability to their livelihood. They often include health, finance, and domestic water usage [19; 22; 25]. The first sub-component of this group is household health [9; 26]. Health characteristics of the household include the proportion of sick people in the household. A household with members that easily get sick or have chronic diseases would limit household labor or burden on household expenses. The supplementary of this factor is direct expenses to health care or annual medical costs [8; 27]. When a household is vulnerable, they can reduce it by having more members buy health insurance. It can cover most of the medical costs when patients have a health checkup or are admitted to the hospital [28].

The second sub-component of sensitivity is finance [3; 23; 29]. Financial capital is one of the most important factors that directly influences household livelihoods. According to other research [6; 20], food is the second sub-component of sensitivity. However, in the context of Vietnam, financial capacity is more relevant [8]. Access to credit or demand for formal and informal loans is an important indicator of household financial capacity [8]. This factor is extremely crucial when households intend to adopt or invest in new livelihood strategies. Income from household activities reflects the financial capacity of the household. It should be noted that the lower the household income, the greater the vulnerability. Finally, the amount or ratio of savings to total household income shows the household's ability to accumulate capital. The positive savings indicate an increase in household assets. It is a chance for households to invest more in education, health, and land [4].

The last sub-component of sensitivity is water resources [19; 22], especially domestic water use for household activities [26]. The percentage of households using tap water or not using tap water is the first indicator [30; 31]. In addition, a number of households still use unsafe water sources for daily life, such as rivers and canals, in increasingly polluted conditions. The shortage of domestic water supply would become more serious due to the natural conditions of saltwater intrusion or drought [30].

The purpose of the study. This paper presents both the results of the combined vulnerability assessment at the household and community level by modifying the method that Hahn et al. [6] proposed. The indicators of exposure, adaptive capacity, and sensitivity were reviewed and adapted to the typical characteristics of Ben Tre province. The results of this study help households and communities assess the influence of saltwater intrusion and other natural factors, as well as their own adaptive capacity and social sensitivity in Ben Tre province. The study was conducted in early 2019 to evaluate the effects of saltwater intrusion in mangosteen growing areas in 2016 and 2018.

Methods of data collection. The basis for selecting the interview households is based on two criteria, perennial trees in the inland of Ben Tre, which was mostly not affected by saltwater intrusion in Ben Tre. The assumptions are farmers of perennial trees. They have more difficulty changing livelihood due to long time investment to the perennial trees when they got affected by the saltwater intrusion. Besides, Cho Lach district, Ben Tre province is famous with many fruit gardens and perennial trees. They have less possibility to get affected by saltwater intrusion. However, saltwater intrusion in 2016 suddenly affected and damaged many fruit gardens, including mangosteen. The survey of 196 mangosteen growers in 2019 was conducted to estimate the impacts of saltwater intrusion on income of mangosteen growers in 2016 and how they changed livelihood strategies (adaptation) in 2018. The study sites are presented in Table 1 and Fig. 1.

Table 1. Study sites and sampling size of mangosteen growers in Cho Lach district, Ben Tre province, Vietnam