Data from: Digging into dirt: Rewilding with threatened mammals shapes soil insect assemblages

Digging mammals function as ecosystem engineers by altering soil
structure, influencing nutrient cycling, and shaping vegetation
communities. The widespread decline of these taxa globally, driven by
habitat loss and introduced predators, has triggered cascading ecological
effects, yet the consequences for soil-dwelling insect communities remain
poorly understood. Insects, many of which have subterranean larval stages,
provide essential functions such as pollination, decomposition and
nutrient cycling, making them ideal indicators for evaluating the
restructuring of ecological communities following mammal reintroductions.
Here, we used data from a long-term experimental mammal exclusion study
within a predator-free sanctuary (Scotia Wildlife Sanctuary) in
southeastern Australia to test how the reintroduction of digging mammals
affects the structure and composition of insect communities emerging from
soil. We sampled insects using emergence traps across replicated plots of
mammal reintroduction, exclusion, and procedural control in 2010 and in
2018, 8 years after fence installation. While variation in digging
activity (indexed by pit density) did not significantly affect richness or
biomass of soil-emerging insect taxa, areas with digging showed reduced
insect abundance. Hierarchical modelling of taxa communities revealed that
parasitoid wasps (Hymenoptera) and predatory robber flies (Diptera:
Asilidae) were strongly associated with plots without digging activity,
likely reflecting sensitivity to direct predation or nest disturbance. No
herbivorous beetle taxa showed a statistically supported association with
treatment, indicating that negative associations with digging activity
were restricted to specific parasitoids and predatory groups, rather than
representing a consistent trophic-wide response. Our findings therefore
indicate that the reintroduction of ecosystem engineers alters insect
assemblages, potentially cascading through to multitrophic interactions
and ecosystem functioning. This is important because it: 1) suggests there
may have been profound effects of the widespread loss of ecosystem
engineers on ecosystems across the Australian continent; and 2) highlights
that whole-of-ecosystem knowledge is critical to getting rewilding right.
We emphasise the importance of thorough, long-term ecological monitoring
of invertebrate assemblages to inform mammal reintroduction and
restoration efforts, ensuring they align with broader ecosystem management
objectives.