[A-HW24] Human- and Climate-induced variability in water cycle and (sub)surface water resources

[AHW24-01] Impacts of land use and climate change on carbon storage and water yield: a case study of the chianan plain, Taiwan

*Ting-You LIN¹、Wen-Chi Chen¹、Sheng-Wei Wang¹ (1.Department of Water Resources and Environmental Engineering, Tamkang University)

キーワード：Water resources, Ecosystem services, Land use, Carbon sequestration

Climate change poses significant challenges to agricultural sustainability, as shifts in precipitation patterns influence both water resource availability and nutrient cycling. Effective climate adaptation strategies require active participation from key stakeholders, including agricultural sectors, farmers, and consumers. The Chianan Plain, located in southwestern Taiwan, is the largest plain in the country, encompassing approximately 40% of Taiwan’s total arable land and contributing 36% of the nation’s annual rice production. As a critical agricultural region, understanding its ecosystem service dynamics is essential for sustainable resource management. This study employs contemporary climate data and land use patterns to assess the carbon storage and water yield capacities of the region, establishing a baseline for future scenario analyses. We applied the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) model to evaluate carbon storage and water yield under the 2016 land use conditions, incorporating data spanning from 2010 to 2023. Key datasets include annual average precipitation, evapotranspiration, soil depth, and carbon pools. Results indicate that in 2016, the total carbon stock within the study area was approximately 62,044,121 tons, with forests exhibiting the highest storage capacity at 437 tons per hectare. In contrast, paddy fields and dry farmland demonstrated comparable values of 70 and 69 tons per hectare, respectively. These findings underscore the superior carbon sequestration potential of forested areas relative to agricultural and other land uses. Given recent policy implementations under the National Land Planning Act, which restricts the conversion of state-owned forests and prime agricultural lands for non-agricultural use, future land-use simulations will be instrumental in evaluating the impacts of large-scale urban expansion on regional carbon stocks. Analysis of annual water yield revealed distinct variations across watersheds based on land use characteristics. The Zengwen River watershed, which encompasses substantial agricultural and mountainous areas, exhibited a 14.68% higher per-hectare water yield compared to the Yanshui River watershed, which is predominantly urbanized. This suggests that landscapes dominated by forests and farmlands contribute more significantly to regional water yield. The study highlights the substantial influence of land use patterns on ecosystem service provisioning. Accurate quantification of land use and land cover effects is critical for sustainable resource management. Integrating biophysical modeling with land-use policy frameworks, such as the National Land Planning Act, can facilitate a deeper understanding of the long-term implications of land-use transitions on ecosystem service values. These findings provide a scientific foundation for evidence-based land management strategies and policymaking, supporting long-term sustainability and climate resilience in agricultural landscapes.