Nature-Based Solutions Reinforce Mekong Food Security

Challenge

Farmers in the Lower Mekong River Basin face rising climate risks that threaten harvests, livelihoods, and already fragile food security.

Solution

Combine climate projections, ecosystem models, and local surveys to pinpoint nature-based practices that strengthen food security.

Overview

Communities in the Lower Mekong River Basin depend on rice, fisheries, and other ecosystem services for daily food and income, but climate change is disrupting rainfall patterns, river flows, and coastal zones. Salinity intrusion, drought, and extreme floods are undermining harvests and degrading land and water ecosystems. Nature-based solutions, which rely on healthy ecosystems to buffer climate risks, offer promising options, but their contribution to food security in this region is still not well quantified.

Loc Huu Ho (Asian Institute of Technology, Thailand) led a project, supported by the Asia-Pacific Network for Global Change Research (APN), to examine how nature-based strategies can help safeguard food security in the basin and how these approaches can be incorporated into adaptation plans.

The project focused on case study provinces in Cambodia, Thailand, and Vietnam and combined climate modeling, ecosystem service assessment, and social surveys. The project team aimed to evaluate how climate change affects ecosystem services that support food production, compile practical examples of nature-based farming practices, and assess how these practices can reduce risk and support resilient food systems. Work packages covered climate impact assessment, documentation of agricultural management practices, evaluation of nature-based options for resilience and food security, and knowledge sharing with policy actors and communities.

Study context and approach

The project centered on three case study provinces in the Lower Mekong River Basin: Nakhon Phanom in Thailand, Siem Reap in Cambodia, and Tra Vinh in Vietnam. The researchers evaluated climate change impacts on water, sediment, and nutrient-related ecosystem services that sustain farming and inland fisheries. Climate projections drew on several global climate models and socio-economic pathways to examine near future, mid future, and far future conditions for each province.

These projections fed into InVEST (Integrated Valuation of Ecosystem Services and Trade-Offs) ecosystem service models to estimate changes in seasonal water yield, sediment delivery, and nutrient retention across farming areas under different land use and climate scenarios. Model results for case study areas such as Tra Vinh, Vietnam, showed that scenarios without nature-based practices reduce nitrogen retention and local water recharge compared with scenarios that include well-chosen nature-based measures.

The project team interpreted these modeling results together with local data on soils, land cover, and farming systems to understand where ecosystem service capacity is likely to decline and how this affects food production and rural livelihoods. This analysis framed discussions of how nature-based solutions could help maintain or improve essential services such as water storage, soil protection, and nutrient cycling.

Nature-based solutions for food security

The team treated nature-based solutions as practical actions that manage land, water, and biodiversity to deliver food while absorbing climate shocks. The researchers reviewed international evidence on nature-based measures in agriculture and collected examples already used by farmers in the three provinces, including mixed cropping, agroforestry, wetland restoration, and water-saving irrigation. To compare options, the team designed a Sustainable Food Security Index covering availability, access, utilization, and stability of food, and paired this with an assessment of ecosystem service benefits and trade-offs under different climate scenarios.

This combined framework allowed the team to see how specific practices influence both ecosystem services and household food security. It also provided a structure for ranking practices by their contribution to resilience, considering local constraints such as land availability, labor, and access to markets.

Stakeholder engagement and capacity development

Household surveys gave voice to farmers and fishers in flood-prone and drought-prone communities and captured their experiences with climate stress, adaptation choices, and food security. The project team organized regional workshops and meetings with government agencies, universities, and civil society organizations to discuss climate risks and nature-based options and to refine survey tools and indicators. Training activities supported local researchers and graduate students in climate impact assessment, ecosystem service modeling, and multi-criteria analysis.

Outcomes and results

• Clarified the Lower Mekong River Basin’s role in global food security, showing that the region accounts for 51% of global rice exports and 22% of the world’s freshwater fish yield.
• Developed 5 climate change scenarios for each study region, covering near future, mid future, and far future periods, and used ensembles of 5 global climate models to explore future flood and drought risks.
• Produced spatial outputs from 3 InVEST models for seasonal water yield, sediment delivery, and nutrient delivery, and used these to identify agricultural areas where ecosystem service capacity is likely to decline under climate and land use change.
• Surveyed 1,000 households in Thailand, Cambodia, and Vietnam (400, 200, and 400 households, respectively) to understand preferences, constraints, and willingness to adopt nature-based practices, and to calibrate indicators for the Sustainable Food Security Index.
• Identified 7 priority nature-based farming practices, including crop rotation with legumes, intercropping with trees, multi-trophic rice–aquaculture systems, crop–livestock–forest systems, and minimum or zero tillage, with preferences that differ strongly between the three provinces.
• Held 3 major workshops in Thailand, including inception, mid-term, and final events, which brought together experts and partners from multiple countries to refine survey tools, discuss results, and train participants on ecosystem service modeling and multi-criteria analysis.
• Produced publications that included 1 published journal article, 1 accepted journal article, 1 journal manuscript under review, and 1 book chapter.
• Engaged 4 PhD students and 3 master’s students in field surveys, modeling, and analysis across the project’s work packages.

Project details

Acknowledgements

This project was supported by the Asia-Pacific Network for Global Change Research (APN) under its Collaborative Regional Research Programme (CRRP). Acknowledgments go to Bethanna Jackson (Victoria University of Wellington, New Zealand), Edward Park (Nanyang Technological University, Singapore), Parmeshwar Udmale (Indian Institute of Technology Bombay, India), Pen Sytharith (Institute of Technology of Cambodia, Cambodia), Houng Peany (Institute of Technology of Cambodia, Cambodia), Long Phi Hoang (Vietnam National University, Hanoi, Vietnam), Thanh Van Pham Huynh (An Giang University, Vietnam), M.S. Shanmugam (Asian Institute of Technology, India), M.A. Mokbul (Asian Institute of Technology, Thailand), and Chloe Pottinger-Glass (Stockholm Environment Institute, Thailand).