Are Soil Nematode Communities Altered by Tree Introduction and Prolonged Cultivation in the Subarctic Region?

Abstract

This study is focused on soil nematode communities in undercrown areas of tree plants introduced to and cultivated for a long time in the botanical garden on Bolshoy Solovetsky Island (Arkhangelsk oblast, Russia). Soil nematode communities of natural forests (pine-, spruce-, and birch stands) are studied as the control. The study has demonstrated that the taxonomic diversity and abundance of nematodes, as well as the proportion of plant parasites in the trophic structure of nematode communities in the soil under introduced trees, are higher compared to natural forests. The ecological indices (structure index SI and enrichment index EI) change nonuniformly and so have poor performance as tools for evaluating the consequences of the plant introductions for the soil ecosystem. Correlation analysis reveals a significant positive relationship between the content of carbon and nitrogen in soil and the absolute and relative abundance and the taxonomic diversity of plant parasites, as well as significant negative relationships between C : N and fungal feeders, as well as between the soil pH and the taxonomic diversity of nematodes and the relative abundance of bacterial feeders and EI. The entomopathogenic nematode Steinernema affine Bovien revealed on the island has been reported for the first time in Russia.