Airborne eDNA documents a diverse and ecologically complex tropical bat and other mammal community

Environmental (e)DNA has rapidly become a powerful biomonitoring tool,
particularly in aquatic ecosystems. This approach has not been as widely
adopted in terrestrial communities where the methods of vertebrate eDNA
collection have varied from the use of secondary collectors such as
blood-feeding parasites and spider webs to washing surfaces of leaves and
soil sampling. Recent studies have demonstrated the potential of direct
collection of eDNA from air sampling, but none have tested how effective
airborne eDNA sampling might be in a biodiverse environment. We used three
prototype samplers to actively sample a mixed neotropical bat community in
a partially controlled environment. We assess whether airborne eDNA can
accurately characterize a high-diversity community with skewed abundances
and to determine if filter design impacts DNA collection and taxonomic
recovery. Our study provides evidence for the accuracy of airborne eDNA as
a detection tool and highlights its potential for monitoring high-density,
diverse assemblages such as bat roosts. Analysis of air samples recovered
>91% of the species present and some limited relationship between
species abundance and read count. Our data suggest this method can
accurately depict a diverse mixed mammal community, particularly when the
location is contained (e.g., a roost, den or burrow) but also highlights
the potential for secondary transfer of eDNA material on clothing and
equipment. Our results also demonstrate that simple, inexpensive,
battery-operated homemade air samplers can collect an abundance of eDNA
from the air, opening the opportunity for sampling in remote environments.