Data for Characterizing the spatial signal of environmental DNA in river systems using a community ecology approach

Environmental DNA (eDNA) is gaining a growing popularity among scientists
but its applicability to biodiversity research and management remains
limited in river systems by the lack of knowledge about the spatial extent
of the downstream transport of eDNA. Here, we assessed the ability of eDNA
inventories to retrieve spatial patterns of fish assemblages along two
large and species-rich Neotropical rivers. We first examined overall
community variation with distance through the distance decay of similarity
and compared this pattern to capture-based samples. We then considered
previous knowledge on individual species distributions, and compared it to
the eDNA inventories for a set of 53 species. eDNA collected from 28 sites
in the Maroni and 25 sites in the Oyapock rivers permitted to retrieve a
decline of species similarity with increasing distance between sites. The
distance decay of similarity derived from eDNA was similar and even more
pronounced than that obtained with capture-based methods (gill-nets). In
addition, the species upstream-downstream distribution range derived from
eDNA matched to the known distribution of most species. Our results
demonstrate that environmental DNA does not represent an integrative
measure of biodiversity across the whole upstream river basin but provides
a relevant picture of local fish assemblages. Importantly, the spatial
signal gathered from eDNA was therefore comparable to that gathered with
local capture-based methods, which describes fish fauna over a few hundred
metres.