Data from: Environmental DNA metabarcoding reveals temporal dynamics but functional stability of arthropod communities in cattle dung

Terrestrial invertebrates are highly important for the decomposition of
dung from large mammals. Mammal dung has been present in most of Earth’s
ecosystems for millions of years, enabling the evolution of a broad
diversity of dung-associated invertebrates that process various components
of the dung. Today, large herbivore mammals are increasingly introduced to
ecosystems with the aim of restoring the ecological functions formerly
provided by their extinct counterparts. However, we still know little
about the ecosystem functions and nutrient flows in these rewilded
ecosystems, including the dynamics of dung decomposition. In fact, the
succession of insect communities in dung is an area of limited research
attention also outside of a rewilding context. In this study, we use
environmental DNA metabarcoding of dung from rewilded Galloway cattle in
an experimental setup to investigate invertebrate communities and
functional dynamics over a time span of 53 days, starting from the time of
deposition. We find a strong signal of successional change in community
composition, including for the species that are directly dependent on dung
as a resource. While several of these species were detected consistently
across the sampling period, others appeared confined to either early or
late successional stages. We believe this is indicative of evolutionary
adaptation to a highly dynamic resource, with species showing niche
partitioning on a temporal scale. However, our results show consistently
high species diversity within the functional groups that are directly
dependent on dung. Our findings of such redundancy suggest functional
stability of the dung-associated invertebrate community, with several
species ready to fill vacant niches if other species disappear.
Importantly, this might also be a potential mechanism buffering the
ecosystem functions related to dung decomposition against environmental
change. Interestingly, alpha diversity peaked after approximately 20-25
days in both meadow and pasture habitats, and did not decrease
substantially during the experimental period, probably due to preservation
of eDNA in the dung after the disappearance of visiting invertebrates, and
from detection of tissue remains and cryptic life stages.