Nitrogen deposition has a significant effect on the forest ecosystem community composition in the context of global change. However, traditional nitrogen deposition researches are generally based on understory nitrogen addition, ignoring the role of canopy process.

Considering that the forest canopy can intercept and utilize a considerable part of nitrogen (for example, leaves can directly absorb and utilize nitrogen), nitrogen deposition may change the plant's inputs (litter and root exudates) and thus affect soil biota which rely on those inputs.

In a research article recently published in the journal Soil Biology & Biochemistry, researchers from South China Botanical Garden of Chinese Academy of Sciences studied the forest soil nematode community structure under canopy nitrogen addition and understory nitrogen addition.They found that understory nitrogen addition significantly inhibits the abundance and diversity of soil nematodes while canopy nitrogen addition has no significant effect on soil nematode communities.

Furthermore, 52% and 44% of the N added to the forest canopy at two N concentration levels were retained by the forest canopy.

This study shows that the forest canopy maintains the soil community composition under elevated nitrogen deposition, which is of great importance for revealing the biodiversity maintenance mechanism under the background of global change, and provides new ideas for future nitrogen deposition research.

For further reading, please refer to: https://doi.org/10.1016/j.soilbio.2020.107733.