An analysis of soil free-living and plant-parasitic nematode communities in three habitats invaded by Heracleum sosnowskyi in central Lithuania

How does an invasive Heracleum sosnowskyi affect soil nematode communities in natural conditions?

“…In the AGRh and REDh plots, the mean nematode abundance and genera numbers decreased, while the MEAh plots were not affected by H. sosnowskyi invasion. In agreement with our results, several previous studies have shown lower total nematode abundance under invasive plant species than under native plants, such as found by Renčo & Baležentiené (2015) in the H. sosnowskyi monocultures that formed in the forest edge, roadside slope and abandoned grassland; Belnap et al (2005), after the exotic grass Bromus tectorum invasion of native Hilaria jamesii; or Zhang et al (2018) after addition of roots and shoots litter of native P. australis vs invasive Spartina alterniflora to soil of non-vegetated area (bare mud flat) without any previous higher plants. This is in contrast with higher nematode numbers detected under the influence of the invasive weed, Ambrosia trifida, which proliferated on abandoned croplands (Liang et al, 2007).…”

“…Predaceous arthropods decreased in response to invasive plants in 44% of studies, which may reflect the indirect effects due to reductions in prey. However, the behaviour and response of large groups of small soil inhabitants, e.g., nematodes, to the incidence of invasive plants have been less well studied (Belnap et al, 2005;Chen et al, 2007;Renčo & Baležentiené, 2015). Furthermore, in previous studies different invasive plant species growing in different ecosystems (habitats) and climatic areas were studied; therefore, results are not comparable or universal.…”

“…To our knowledge, data on the relationship of some of the invasive Heracleum species and soil nematodes are scarce. Databases include only our previous work on H. sosnowskyi performed in central Lithuania (Renčo & Baležentiené, 2015), where a long-term H. sosnowskyi dominance was associated with low abundances and faunal similarity of soil nematode communities, despite the fact that several nematode trophic groups (bacterivores, root fungivores, omnivores) and nematode species were not sensitive to invasion. However, due to the wide habitat preference of H. sosnowskyi, generalisations about the H. sosnowskyi impact on soil nematodes is problematic because only three invaded habitats on one locality have been examined (Renčo & Baležentiené, 2015).…”

Soil ecology of the exotic dune grass Leymus arenarius.

“…However, at a local scale, plants can also have strong influence on soil communities (Johnson et al 2003;Marschner et al 2004). In particular, changes in dominant plant identity, for example due to exotic plant invasions or habitat restoration efforts, have been shown to alter soil community structure and function of bacteria (Batten et al 2006;Hawkes et al 2005;Kourtev et al 2002;Urbanová et al 2015), fungi (Lankau et al 2014;Mummey and Rillig 2006), and invertebrates (Chen et al 2007;Renčo and Baležentiené 2015;Tanner et al 2013;Xiao et al 2013), often through changes in carbon inputs via litter or root exudation. Exotic plants may also alter soil communities via suppression of belowground herbivores and pathogens, the "enemy release hypothesis" (Heger and Jeschke 2014), though application of the enemy release hypothesis belowground has been debated (Colautti et al 2004).…”

“…Several recent efforts have improved understanding about the belowground impacts of exotic plant invasions. For example, exotic plant invasions alter soil communities through changes to bacteria (Kourtev et al 2002), arbuscular mycorrhizal fungi (Lankau et al 2014;Mummey and Rillig 2006), and invertebrates (Chen et al 2007; Renčo and Baležentiené 2015;Tanner et al 2013;Xiao et al 2013). Even after removal of the exotic plants, negative soil legacy effects created by the exotic plant may impede full recovery of the community to its pre-invasion state (D'antonio and Meyerson 2002).…”