Topographic controls on ecosystem evapotranspiration and net primary productivity under climate warming in the Taihang Mountains, China

Abstract

Topography is a key control of mountain ecosystems and the corresponding ecohydrological processes in mountain environments. This study examines the influence of topography on variations in mountain ecohydrology under climate warming in the Taihang Mountains in China. The BioGeochemicalCycles (BIOME–BGC) ecosystem model was modified and used to evaluate ecosystem evapotranspiration (ET) and net primary productivity (NPP) for deciduous broadleaf trees, shrubs and grass at different elevation gradients and examine the changes in these variables under a 3 °C–warming scenario with no precipitation changes. The results showed that the ET and NPP of deciduous broadleaf trees and shrubs increased with elevation below 1500 m and decreased with elevation above 1500 m. The NPP and ET of deciduous broadleaf trees and shrubs decreased in response to warming below 1500 m, and increased above 1500 m. For grass, the ET and NPP slightly decreased with greater elevation and increased under climate warming. Combined with the influence of precipitation on ET and NPP, the response to warming can be explained as follows: deciduous broadleaf trees are under water stress in low–middle elevation and under energy stress in high elevation. Shrubs were influenced by water conditions with an optimal precipitation of 600 mm at low–middle elevation and under energy stress in high elevation. Grass was under energy stress at all elevations. The results of this study are important for identifying topographic and climate change impacts on mountain ecosystem and can provide support for planning and management of future ecosystem restoration in the Taihang Mountains.