Effects of Naphthalene Application on Soil Fungal Community Structure in a Poplar Plantation in Northern Jiangsu, China

The soil food web is essential for the functioning of terrestrial ecosystems. The application of naphthalene is a commonly employed experimental treatment for expelling soil fauna to examine faunal effects on litter decomposition processes, for which is it assumed that naphthalene has negligible effects on soil microbial communities. An experiment was conducted to examine the potential soil-fauna-repellent effect of naphthalene application (100 g/m(2)/month, TR) on a soil fungal community during litter decomposition. The results showed that TR greatly suppressed the abundance and taxonomic richness of soil fauna by 83.7 +/- 14.2% and 48.1 +/- 17.2%, respectively, and reduced the rates of poplar leaf litter decomposition compared to the control (CK, without naphthalene treatment). Among the fungal communities, the abundance of Thelephorales in the TR soil was suppressed, while the abundance of Capnodiales was stimulated, although TR did not significantly alter the carbon and nitrogen content in the soil microbial biomass nor the diversity of soil fungal communities and the most abundant fungal phylum. Thus, both the suppressed soil arthropod abundance and altered soil fungal community might contribute to the observed slowdown in litter decomposition. These results suggest that naphthalene, as a soil fauna repellent, can alter the abundance of specific taxa in a soil fungal community, thereby impeding the effort to elucidate the contribution of soil fauna to ecosystem functioning (e.g., with respect to litter decomposition).

Automated summary

The soil food web plays a crucial role in terrestrial ecosystems. Naphthalene is commonly used to expel soil fauna for studying their effects on litter decomposition, assuming negligible impacts on soil microbial communities. However, experiments showed that naphthalene significantly suppressed soil fauna abundance and altered soil fungal community composition, resulting in a slowdown of litter decomposition. These findings suggest that naphthalene can alter specific taxa in the soil fungal community and impede the understanding of soil fauna's contribution to ecosystem functioning.