The ecology of aboveground terrestrial eDNA: Its state, transport, and
fate on aboveground surfaces
Abstract
Environmental DNA (eDNA) analysis has become a valuable tool for
detecting aquatic and terrestrial species for monitoring efforts and
site biodiversity assessments. However, if aboveground terrestrial eDNA
surveys are to be widely adopted, it is necessary to first understand
how terrestrial conditions affect the state, transport, and ultimate
fate (or ‘ecology’) of terrestrially deposited eDNA. Many of the
processes that affect the state, transport, and fate of eDNA in aquatic
environments may not be applicable in aboveground systems, warranting an
exploration of the terrestrial processes that likely do affect eDNA.
Here we explore the ecology of aboveground terrestrial eDNA through a
series of experiments evaluating the optimal filter pore size for
intracellular eDNA collection, how eDNA is affected by rain events, and
its degradation rate under different solar radiation conditions. We
found that the captured concentration of intracellular eDNA was not
significantly affected by an increase in filter pore size, suggesting
there is a wide range of viable pore size options for targeting
intracellular eDNA. We also found extracellular eDNA degrades more
rapidly than intracellular forms when exposed to solar radiation,
indicating the latter is a more viable target for collection. Finally,
we identified that rainfall or mist will remove most terrestrial eDNA
present on vegetation substrate. This study provides researchers and
managers key insights into successfully designing and carrying out
terrestrial eDNA surveys that maximize detection probability and
minimize false positive results.