Non-native earthworms have been invading North America since European settlement. Compared to temperate forests, their presence in the boreal forest is much more recent and thus remains understudied, despite the potential threat they represent for soil carbon (C) stocks. Here we compared earthworm-invaded and earthworm-free zones in soil types representative of the boreal forest, including Luvisols, Podzols, and Brunisols (Cambisols). We observed that the forest floor (surface organic layer, or LFH) decreased in thickness after invasion in most cases and developed into a Vermimull, with the loss of the most humified layer (humic or H horizon). Simultaneously, the surface mineral horizon was reworked by earthworms into a novel Ahu horizon, characterized by higher organic matter and enriched in earthworm casts. Forest floor C stocks decreased by 94% and 59% for Luvisols and Brunisols respectively, while those of Podzols remained apparently unaffected. Mineral soil C stocks in Brunisols increased after invasion, while no changes were observed in Luvisols and Podzols. Our results demonstrated the substantial impact that invading earthworms are having on soil morphological features and C stocks in boreal forests. Effects were similar to what has been reported for temperate forests, although the degree of impact depended on soil type. While C stocks were less affected in the mineral soil compared to the forest floor, the development of a novel surface horizon reworked by earthworms could alter microbial dynamics and impact mineral C persistence. Further research is needed to quantify long-term implications of earthworm presence for boreal soil C stocks.

自欧洲定居以来，非本地蚯蚓一直在入侵北美。与温带森林相比，它们在北方森林中出现的时间要晚得多，因此仍未得到充分研究，尽管它们对土壤碳 (C) 储量构成潜在威胁。在这里，我们比较了代表北方森林的土壤类型中的蚯蚓入侵区和无蚯蚓区，包括 Luvisols、Podzols 和 Brunisols（Cambisols）。我们观察到，在大多数情况下，森林地面（表层有机层，或 LFH）在入侵后厚度减少，并发展为蚯蚓，失去最腐殖化的层（腐殖质或 H 层）。同时，地表矿物层被蚯蚓改造为新的阿湖层，其特征是有机质含量较高，富含蚯蚓粪。Luvisols 和 Brunisol 的林地 C 库分别减少了 94% 和 59%，而 Podzols 的那些显然没有受到影响。Brunisols 中的矿物土壤碳储量在入侵后增加，而 Luvisols 和 Podzols 中没有观察到变化。我们的研究结果表明，入侵的蚯蚓对北方森林的土壤形态特征和碳储量产生了重大影响。尽管影响程度取决于土壤类型，但影响与温带森林报告的影响相似。虽然与森林地面相比，矿物土壤中的碳储量受到的影响较小，但由蚯蚓改造的新型地表层的发展可能会改变微生物动态并影响矿物碳的持久性。需要进一步研究来量化蚯蚓存在对北方土壤碳储量的长期影响。