Invasive earthworms affect soil morphological features and carbon stocks in boreal forests

Gray Luvisols are polygenetic

“…The Ahe horizon thickness was 2 and 4 cm at Breton and Winfield, respectively. More recently, Lejoly et al (2021) reported the presence of an 8-cm-thick, Ahu horizon with granular structure underlying the LFH horizon at Breton (Table 3). A third pedon in the forest preserve at the Breton plots was observed to have a 13 cm thick Ahu horizon underlying the LFH horizon.…”

“…There is also evidence to suggest that increased earthworm activity in forested Luvisolic soils has altered the soil carbon balance of the mineral A horizons in the last 30-40 years. Lejoly et al (2021) sampled pedons in the forest preserve at the Breton Plots showing significant evidence of earthworm activity (Ahu horizons) and these pedons have a markedly different soil carbon distributions compared to the forested pedons sampled by Izaurralde et al (2001) and Howitt and Pawluk (1985). Lejoly reported SOC stocks of 3.3 Mg ha -1 in the LFH (4 cm thick) and 35.3 Mg ha -1 in the top 10 cm of mineral soil, compared to the 1979 and 1981 estimates of 43 and 40 Mg ha -1 in the LFH (10 and 8 cm thick) and 17 and 14 Mg ha -1 in the top 18 and 17 cm of mineral soil, respectively.…”

“…The Ae horizons described by Pawluk (1980) and Martin et al (1987) had weak or moderate platy structures and were 12 and 14 cm thick. Lejoly et al (2021) reported Ahe horizons that were 2 -3 cm thick with platy structures. The third pedon in the forest preserve had a 25 cm thick Ahe horizon with platy structure (Table 3).…”

“…In comparison, in Alaska, 50% of the low human-impact sites sampled by Saltmarsh et (2016) were invaded. Compared to other soil types, A horizons of Gray Luvisols are potentially more affected by earthworm invasion compared to other orders because they form de novo organo-mineral complexes (Lejoly et al 2021).…”

Do the Invasive Earthworms Amynthas agrestis (Oligochaeta: Megascolecidae) and Lumbricus rubellus (Oligochaeta: Lumbricidae) Stimulate Oxalate-Based Browser Defenses in Jack-in-the-Pulpit (Arisaema triphyllum) by Their Presence or Their Soil Biogeochemical Activity?

“…Specifically, the invasion of woodlands by earthworms results in the loss of organic soil horizons (through consumption of the O e and O i layers) and a mixing of organic and mineral material [5], setting off an ecological cascade of effects that reach well beyond the forest soil and the immediately affected ecosystem [6]. With invasions now reaching into the ecosystems of the arctic circle [7,8], earthworms may affect the vast stocks of carbon stored in the taiga and tundra soils [9,10]. In the temperate regions of North America, the invasion is already well advanced and is affecting the plantsoil system [11][12][13], as well as whole ecosystems [1].…”