Advances in Effect of Nitrogen Deposition on Soil Nematode Communities

Abstract:

The increase of nitrogen deposition has altered ecosystem structure and function. As key bioindicators of soil ecosystems, soil nematodes have important ecological implications. With the globalization of nitrogen deposition, it has attracted widespread attention on how elevated nitrogen inputs affect soil nematode. The response pattern and mechanism of soil nematodes to elevated nitrogen deposition in terrestrial ecosystems (grassland, farmland and forests) were reviewed. In general, elevated nitrogen deposition had no significant effects on the number of soil nematodes, but increased the number of enrichment opportunist (i.e. r-strategy nematodes with low trophic levels) and decreased soil nematode maturity index (MI), indicating that the increase of nitrogen inputs might simplify soil food webs. Moreover, elevated nitrogen deposition could affect the soil nematode community directly by changing soil microenvironment, such as increased NH₄⁺ and NO₃^- concentration and decreased soil pH, or indirectly by changing plant resource inputs and the relationships between the nematodes and other soil biota. In the end, some limitations of previous studies were pointed out, including temporal and special scales, and measurement techniques. To better understand the effects of global environmental changes, it is urgent to explore how multiple global change factors affect soil nematode communities across different terrestrial ecosystems. It was suggested to combine both molecular biology techniques and laboratory incubation methods in the future.