Impact of bedrock geochemistry on vegetation productivity depends on climate dryness in the Guizhou karst of China. (February 2021)

• Record Type: Journal Article
• Authors: Zhu, Xinrong; Liu, Hongyan; Wu, Lu; Liang, Boyi; Liu, Feng; He, Wengqi
• Other Names: Liu Hongyan guest-editor.; Peng Jian guest-editor.
• Is Part Of: Progress in physical geography. Volume 45:Number 1(2021)
• Page Start: 20
• Page End: 32
• Publication Date: 2021-02
• Subjects: Karst -- Climate -- Bedrock geochemistry -- Random forest -- structural equation model (SEM) -- GPP; Physical geography -- Periodicals; 910.02
• DOI: 10.1177/0309133320936085
• Languages: English
• ISSNs: 0309-1333

Abstract

The Guizhou karst area is one of the largest continuous areas of karst in the humid climate zone and is representative of karst landforms in China. Large portions of the karst system are characterized by extremely shallow soils underlain by weathered bedrock and water deficits are common. Although the distribution of ecosystem productivity is largely related to variations in the temperature and precipitation, the influence of the substrate in karst areas requires further exploration. We explored the relative importance of the bedrock geochemistry (characterized by the concentrations of Ca, Mg and Si) and climatic factors (temperature and precipitation) to explain the spatial variability in gross primary productivity (GPP) with various degrees of water deficit during the time period 2001–2015. Our results show that the impact of bedrock geochemistry is an important parameter in changing the original relationship between climate and the GPP. The bedrock geochemistry functioned as a "regulator" of the relation between climate and the GPP, which strengthened with decreasing climate favourability. The variations in GPP and surface water storage were significantly different when different elements (Ca, Mg or Si) were dominant. The Mg-rich regions showed the greatest annual variations in the GPP, whereas the Si-rich regions had the strongest surface water storage potential to support vegetation growth. The results of our study are important for systematically evaluating the effects of climate on vegetation productivity and provide a benchmark for global vegetation modelling predictions.