Detecting and Attributing the Impact of Human Activities on Grassland Aboveground Biomass in China's Loess Plateau

Abstract

Human activities are affecting grassland ecosystem functions, especially plant biomass. However, the direction and magnitude of their effects on plant biomass still remain underexplored. Herein, we quantitively assessed both the positive and negative effects of various human activities on grassland aboveground biomass (AGB) in China’s Loess Plateau from 2000 to 2022. The results showed that the magnitudes of the positive and negative effects increased by 0.29 g m−2 per year and decreased by 0.31 g m−2 per year, respectively. Spatially, 32 % of the grasslands experienced significant positive effects, whereas the rest grasslands faced negative effects. Notably, only 20 % of the areas with negative effects showed worsening trends mainly due to ecological restoration, sustainable agriculture, and population migration. Agricultural production activities and population changes emerged as dominant factors, with some activities, like livestock farming, exhibiting dual effects (i.e., positive and negative effects) on AGB. These findings underscore the complexity of human activities in affecting the grassland production function and highlight the necessity for balanced management strategies to sustain grassland productivity and resilience.

Keywords: Aboveground biomass, Human activities, Effect magnitude, Spatiotemporal attributions, grasslands, Loess Plateau