Data from: Tracking the phenology of riverine insect communities using environmental DNA

The data contains three datasets and one R scripts used in the article
"Tracking the phenology of riverine insect communities using
environmental DNA". The three datasets contain the
following:  Presence/absence of aquatic insects based on eDNA
sampling Information on the sampling sites Permutation tests Aquatic
insects are iconic and ecologically highly relevant inhabitants of
riverine ecosystems. They are also often the target of monitoring programs
to assess the ecological status of these lotic habitats. Environmental DNA
(eDNA) techniques have been widely and successfully implemented to
investigate freshwater insects and other macroinvertebrates. Commonly,
such monitoring is conducted at one or two timepoints per year, despite
the known phenology of aquatic insects' life history strongly
affecting species presence—or detection—and population dynamics through
the seasons. Here, we assessed if and to which extent eDNA can capture the
temporal changes of the orders Ephemeroptera (mayflies), Plecoptera
(stoneflies), Trichoptera (caddisflies), and Diptera (true flies). We
carried out eDNA sampling at roughly monthly intervals from April to
October at 25 sites across a whole river catchment in the northeastern
part of Switzerland. We found pronounced, cyclic phenological trends in
all orders but Trichoptera: the communities diverged from spring to summer
and then in fall gradually returned closer to the spring state. The four
orders exhibited different predominance in gains or losses of species
detection throughout this time interval. Lastly, we found that field
replicates, despite showing a relatively high local stochasticity, were
able to provide a more complete assessment of aquatic communities. Field
replicates, when used as a proxy for the frequency of observation of a
species through the seasons, yielded comparable temporal patterns to the
ones extracted from the Global Biodiversity Information Facility (GBIF)
for about 35% of the investigated species. Overall, our findings
demonstrate that eDNA techniques can be used to reveal intra-annual
dynamics of aquatic insects. Given the current necessity to assess and
monitor the biodiversity status of ecosystems, we therefore show that eDNA
methods are a viable option to obtain a deeper understanding of the
structuring of freshwater communities over time.