Plant invasions from a belowground nematocentric perspective

We examined the impact of plant-soil biota feedbacks set in motion by the exotic plants in 2 × 2 factorial (species × location) field and microcosm experiments both within the invasive as well as natural range of both plant species using a metagenetic nematocentric approach. The results were inconsistent and did not lend themselves to simple generalizations as responses of nematode community composition patterns were specific to plant species, locations, years, and even to experimental conditions. For instance, greater diversity of plant-parasitic nematodes was confirmed for both plant species in their native ranges, but only in the field surveys (not microcosms) and only in the first year of sampling (not the second). Equally importantly, the specificity was only observed at the “near species” level allowed by the metagenetic approach and as the identification of nematodes became less resolved, i.e., as identification moved from the “near species”-level to coarser levels of taxonomic resolution, the specific responses generally diminished.