Scientists uncover core stabilizing driver of grassland productivity

LANZHOU -- A joint study by Chinese and international scientists has newly revealed the core driving factor that helps maintain stable productivity of grassland ecosystems, according to Lanzhou University, located in Northwest China's Gansu province.

The new study shows that species diversity within local grassland communities is the key driver of productivity stability in China's natural grasslands, the university noted.

Led by the College of Ecology of Lanzhou University, in collaboration with researchers from institutions in the Netherlands and Spain, these findings have been published in the journal Nature Communications.

"The findings of our study provide a new perspective for understanding and predicting the stability of grassland ecosystems given the context of global climate change," said Liu Xiang, professor at the College of Ecology of Lanzhou University.

Climate change and biodiversity loss caused by human activities are profoundly affecting the stability of ecosystem functions, and the ecological community has for long believed that higher species diversity promotes ecosystem stability.

Earlier evidence demonstrated that local functional trait composition and diversity along the fast-slow leaf economics spectrum can predict the temporal stability of community productivity in response to environmental changes. Scientists initiated this new study to investigate whether these relationships persist at larger spatial scales, Liu said.

Focusing on typical arid and cold region ecosystems such as the Qinghai-Tibet Plateau and the Inner Mongolia Plateau in China, the study team carried out systematic field investigations.

Researchers set up 235 grassland sampling sites and measured plant species composition, functional traits and the physical and chemical properties of soil in these communities. They also used remote sensing data, spanning a decade, to track interannual variations in vegetation productivity at each site.

By combining community information obtained from field investigation with long-term productivity dynamics, the team analyzed the temporal stability of grassland productivity across multiple spatial scales.

The study determined that species richness contributes to the stabilizing of productivity, while functional diversity contributes to destabilizing productivity at the local scale. In contrast, the study found no evidence that differences in species composition or functional traits among local communities enhance stability at larger spatial scales via asynchronous fluctuations in productivity among local communities, according to Liu.

The relationships between environmental conditions, local diversity and stability differ among regions. On the Inner Mongolia Plateau, where water limitation predominates, mean annual precipitation is the key stabilizing factor for grassland productivity. In contrast, on the Qinghai-Tibet Plateau, where temperature constraints are dominant, species richness within local communities is the key factor, the study showed.

"By combining large-scale field investigation with long-term remote sensing observation, our new study confirmed the crucial role of species diversity within local communities in maintaining the stability of grassland productivity," Liu said.

"Furthermore, it provides a new scientific basis for the sustainable management of grasslands, especially in arid and cold regions," he added.