A sustainable-livelihood framework was followed to guide vulnerability assessment. Vulnerability context is a major determinant of a sustainable-livelihood framework that is mainly based on 5 livelihood assets, namely, human, social, natural, physical, and financial capital, and directly influences the institutional process, and livelihood strategies and outcomes. The study chose 2 local administrative units (Upazila) of Gaibandha district, namely, Saghata and Fulchhari Upazila. These areas are around 287 km from the capital of Dhaka and the northern part of Bangladesh. These areas comprise natural-hazard-prone and geographically isolated riverine areas. The study areas are riverine islands (chars) in Jamuna River, which faces huge riverbank loss every year. Frequent flood inundation and riverbank erosion are regular phenomena in these areas. The study areas were purposively selected considering natural-hazard severity, based on obtained information from literature reviews, expert opinions, available reports, and newspapers. The respondents for this study were selected randomly from the study areas.
2.1. Data Collection The study used a questionnaire survey and focus-group discussions (FGDs) for data collection regarding livelihood assets, sociodemographic profiles, vulnerability indicators, and adaptation strategies. The questionnaire pilot was tested on 25 respondents to determine its suitability for the study and avoid any exaggeration in the questionnaire. The sample size was determined by the following formula, developed by Yamane. This formula has been popularly used by researchers for determining household sample size for livelihood research.
The total population in the study area was 5666. Therefore, sample size was 374 for this study. Data were collected from the head of every household by face-to-face interviews using a semistructured questionnaire. The questionnaire survey and FGDs for this study were conducted from January to August 2017. Oral consent was taken from the household head prior to the interview. The interviews were done in the local Bengali language and lasted an average of 50 min. One FGD was done comprising 10–12 household heads in every village to record opinions regarding socioeconomic and climate-related variables that were used to validate the obtained data from the questionnaire survey. Differences in vulnerability status between households living nearby villages (in Saghata Upazila), and households living distant villages from the mainland (in Fulchhari Upazila) were determined by chi-square and t-test.
2.2. Vulnerability Analysis Vulnerability is a condition of an individual or community to stresses due to changes in socioeconomic and environmental conditions disrupting livelihoods. Vulnerability assessment can identify susceptible people and the context of natural hazards through exploring socioeconomic processes and natural outcomes. According to the IPCC, vulnerability is a function of 3 dimensions: exposure, sensitivity, and adaptive capacity. Vulnerability = ƒ (exposure, sensitivity, adaptive capacity).
Generally, vulnerability is positively related to a system’s exposure and sensitivity, but negatively related to adaptive capacity. The livelihood vulnerability of char dwellers was measured by an LVI and CVI, focusing on major determinants under the appropriate IPCC framework. The IPCC framework uses 3 major factors (exposure, sensitivity, and adaptive capacity) to measure vulnerability. This study used a composite index-oriented LVI, which comprises the human, natural, physical, social, and financial household capital of a sustainable-livelihood framework (SLF) to provide better integration with sensitivity and adaptive capacity. This kind of methodology has been used by other scholars. The main limitation of SLF is its inability to integrate the indicators of sensitivity and adaptive capacity. In this study, the LVI approach deals with a group of 13 major components consisting of major indicators and sub-indicators under 5 categories of livelihood capital (human, natural, physical, social, and financial capital). It comprises health, food, water, knowledge, livelihood strategies, land, natural resources, natural disasters, climatic variability, social networks, housing and production means, and agricultural and nonagricultural assets. This context-specific LVI approach can properly explore the real circumstances of livelihood vulnerability caused by natural disasters.