Soil Springtail Communities Are Resilient to Forest Tent Caterpillar Defoliation in Quebec Mixed Hardwood Forests

Outbreaks of defoliator insects are important natural disturbances in boreal forests, but their increasing frequency under warming climate conditions is concern. Outbreak events can shape ecosystem dynamics with cascading effects through trophic networks. Caterpillar defoliation alter tree physiology, increase sunlight to the understory, and result deposition large amounts leaf litter caterpillar frass forest floor. These modifications thus affect soil organisms direct (e.g., changes temperature or moisture) indirect detrital root food webs) mechanisms. We assessed whether a recent (2015 2017) outbreak tent (Malacosoma disstria) at Lake Duparquet Teaching Research Forest (Abitibi, QC, Canada) affected springtail communities, abundant microarthropods soils. In 2018 2019, we sampled (0–10 cm depth) eight sites each aspen-dominated (Populus tremuloides Michx) stands that were undefoliated had history. found no significant difference abundance (specimens cm−2) alpha diversity indices between those However, observed transient change community composition 1 year after (2018) absence Folsomia nivalis, Anurophorus sp1, Xenylla christianseni history, compositional differences 2019. Certain nutrients (P, C, Mg, Mn) predictors composition, microbial biomass was not, despite its decrease Our results show communities respond short-term shifts, seem ultimately resilient these events.