Nitrogen addition affects trait divergence of plant community assembly

It is well known that nitrogen (N) deposition can affect plant community assembly in the temperate desert steppe, thus resulting in changes in local ecosystem functions and species diversity.

A research team from the Northwest Institute of Eco-Environment and Resources of the Chinese Academy of Sciences (CAS) conducted a four-year N addition experiment with eight N addition levels to investigate the underlying plant community assembly mechanisms in the temperate desert steppe of Inner Mongolia.

The researchers investigated species composition and then collected aboveground biomass and measured six soil properties and functional traits. They also examined changes in six trait ranges and trait patterns along experimental N addition gradients.

Their results were published in Plant and Soil on Feb. 13.

According to the researchers, environmental and biotic filtering plays important roles in community assembly along N addition gradients in a temperate desert steppe. The effects of environmental and biotic filtering on plant community assembly can be revealed by progressively examining changes in trait ranges and trait patterns along N addition gradients.

High N addition also alters species diversity and composition. In N-rich communities, traits tend to diverge because species with opposite ecological strategies show small differences in their competitive ability and thus coexist abundantly, suggesting that high N addition induces functional trait differentiation and trait dissimilarity drives plant community assembly.

This study contributes to our understanding of the mechanisms underlying the emergence and maintenance of biodiversity in the temperate desert steppe and provides a theoretical basis for the conservation and sustainable development of ecosystem functions and ecosystem services.