Abstract
Background
Ecosystem service supplies (ES) have experienced progressive decline mostly due to increased ES social demand. Identifying ecosystem supply (ES), social demand, and their impacts on smallholder farmers' well-being is essential to ensure sustainable utilization of ES. Quantitative studies assessing ES mostly focused on ES supply with little attention given to social need and its effects on human well-being.
Methods
We assessed and mapped selected ES supply, social demand and their mismatches, and evaluated their impacts on subjective well-beings of smallholder farmers in contrasting agro-ecological zones (AEZ). We used a questionnaire survey to analyze and map six provisioning ecosystem services (ES) focusing on ES supply, social demand and their mismatches. Using the universal soil loss equation (USLE), we mapped the rate of soil loss in the contrasting agro-ecological zones (AEZ). A participatory approach was employed to evaluate smallholder farmers' well-being in the study region. Radar diagram was used to identify the links between ES supply, social demand and smallholder farmers' well-being.
Results
The results showed that a high supply of provisioning ecosystem goods such as cereal crops, fruits and coffee occurred in humid AEZ, while less supplies were seen in semi-arid AEZ of the study region. The ES supply was not in accordant with ES social demand and different factors such as population size and level of production are among the main factors causing ES supply-demand mismatches. Due to the undulating topography, high rate of soil loss was seen in humid AEZ. Smallholder farmers have given higher values for soil erosion control compared with individuals from semi-arid AEZ. Of all indicators of smallholder farmers well-being, income had the highest weight while receiving the least well-being satisfaction level both in humid and semi-arid AEZs.
Conclusion
The mismatches between supply and demand in provisioning ecosystem supply had strong and immediate impacts on smallholder farmers well-being. Therefore, we suggest policies that effectively control population growth, applying intensive crop production and strengthening integrated watershed management. These policies would help ES to recuperate and enhance its continuous flow and improve smallholder farmers' well-being both in the humid and semi-arid AEZ of the study region.
Quantifying ecosystem service supply-demand relationship and its link with smallholder farmers’ well-being in contrasting agro-ecological zones of the East African Rift
