Precipitation is a primary determinant of plant community structure in drylands. However, empirical evidence and predictions for how plant functional diversity in desert and steppe communities respond to altered precipitation regimes are lacking.

Yu Qiang, research fellow from the Institute of Agricultural Resources and Regional Planning (IARRP), Chinese Academy of Agricultural Sciences (CAAS), and Zuo Xiaoan, research fellow of the Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS) examined how precipitation changes along the natural and experimental gradients affect different components of functional diversity in desert - shrub and steppe - grass communities. They also disentangled the roles of species turnover and intraspecific variations in affecting the responses of different functional diversity to precipitation changes.

The results show that in general the similar responses of functional traits or diversity to both the natural and experimental precipitation gradients were dependent on plant community type; however, the relationship between the functional diversity to precipitation changes of grass and shrub communities and their influencing mechanisms are different. Precipitation was positively associated with plant functional traits in grass community, while positively associated with functional divergence (FDvar) and functional dispersion (FDis) in shrub communities.  

These results suggest different responses to precipitation changes between shrub and grass communities. Both species turnover and intraspecific variations contributed to the responses of grass community traits to precipitation changes across both gradients, and to functional divergence of traits and FDis in shrub communities along the natural gradient. In contrast, species turnover variations contributed to functional divergence of traits and FDis in shrub communities in experiment gradient. 

Explained variability of interspecific and intraspecific variations contributed to the responses of grass community traits to precipitation changes, and to functional divergence (FDvar) of traits and FDis in shrub communities. On the left is natural gradient and on the right is experiment gradient.

The research results were published in Functional Ecology (IF=5.61) titled Functional diversity response to geographic and experimental precipitation gradients varies with plant community type. Research fellow Zuo Xiaoan from the Northwest Institute of Eco-Environment and Resources, CAS is the first author, and research fellow Yu Qiang from the IARRP, CAAS is the corresponding author.

This research was jointly funded by the National Natural Science Foundation of China (42071140, 41622103) and China’s Second Scientific Expedition on the Qinghai-Tibet Plateau Project (2019QZKK0305).

https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2435.13875