Evaluating restoration trajectories using DNA metabarcoding of
invertebrates and their associated plant communities
Abstract
Invertebrate communities provide many critical ecosystem functions (e.g.
pollination, decomposition, herbivory and soil formation), and have been
identified as indicators of ecological restoration. Unfortunately,
invertebrates are often overlooked in restoration monitoring because
they are time-consuming to survey, often require rare taxonomic
expertise, and there are many undescribed species. DNA metabarcoding is
a tool to rapidly survey invertebrates and can also provide information
about plants with which those invertebrates are interacting. Here we
evaluate how invertebrate communities may be used to determine ecosystem
trajectories during restoration. We collected ground-dwelling and
airborne invertebrates across chronosequences of mine-site restoration
in three ecologically different locations in Western Australia, and
identified invertebrate and plant communities using DNA metabarcoding.
Ground-dwelling invertebrates showed the clearest restoration signals,
with communities becoming more similar to reference communities over
time. These patterns were weaker in airborne invertebrates, which have
higher dispersal abilities and therefore less local fidelity to
environmental conditions. Invertebrate community recovery was most
evident in ecosystems with relatively stable climax communities, while
the trajectory in the Pilbara, with its harsh climate and unpredictable
monsoonal flooding, was unclear. Plant assay results indicate
invertebrates are foraging locally, providing data about interactions
between invertebrates and their environment. Thus, we show how DNA
metabarcoding of invertebrate communities can be used to evaluate likely
trajectories for restoration. Testing and incorporating new monitoring
techniques such as DNA metabarcoding is critical to improving
restoration outcomes, and is now particularly salient given the
ambitious global restoration targets associated with the UN decade on
Ecosystem Restoration.