Evaluation of the effects of climate change on forest watershed hydroecology using the RHESSys model: Seolmacheon catchment

Abstract

This study examines the effects of future climate changes on watershed hydroecology, including runoff, evapotranspiration, soil moisture content, gross primary production (GPP), and photosynthetic productivity (PSNnet), by applying the Regional Hydroecological Simulation System model to the Seolmacheon catchment (8.5 km2). Based on the daily runoff, evapotranspiration, and soil moisture content in the watershed from 2007 to 2009, calibration (2007–2008) and validation (2009) of the model were conducted. By utilizing PSNnet and GPP data collected with the Moderate Resolution Imaging Spectroradiometer sensor onboard the Terra satellite, model calibration (2007) and validation (2008) were implemented. For future climate change data, the MIROC3.2 (hires) and the HadCM3 climate change scenarios (A1B and B1), which were provided by the IPCC, were used for reference. Compared to the baseline period, the future temperature increased by a maximum of + 4.9 °C in the MIROC3.2 A1B scenario, and precipitation increased substantially in spring and winter. In the hydrological evaluation, MIROC3.2 showed annual change rates from − 33.9 to 6.0%. Both the A1B and B1 scenarios showed 6.0% and 1.0% increases in the 2020s and − 33.9% and − 32.8% decreases in the 2080s, respectively. For HadCM3, the A1B (B1) scenario showed rates of − 9.9% (1.4%), − 48.6% (− 19.2%), and − 42.4% (− 32.1%), in the 2020s, 2050s, and 2080s, respectively. Because climate region movement is relatively slow for temperature ranges when plant movement increases, existing forests might survive in their minimum state or vanish under extreme conditions, such as heat stress, droughts, and fires. In the simulation, the evapotranspiration volume, which was closely related to vegetation, caused the average annual temperature to increase by 2.6–3.6 °C, which caused local vegetation to vanish.