AT THE INTERSECTION OF ECOLOGY AND GENOMICS
eDNA and Invasive Species
Anthropogenic impacts on landscapes have created opportunities for invasive species to spread, causing biodiversity loss. Large-scale biodiversity loss contributes to the degradation of ecosystem functions and services, creating a need to better understand invasive species’ impacts on systems. An emerging technology that can be used to characterize changes in biodiversity is environmental DNA (eDNA), which is genetic material that is collected from the environment. Currently we are using airborne eDNA to investigate the impacts of hemlock woolly adelgid (HWA) on hemlock ecosystems. HWA is a small invasive insect that has decimated hemlock forest in the eastern United States (US) and is spreading westward in the Midwest regions of the US and Canada.
Kate Geller, an undergraduate student in our lab, designed a 3D printed trap that holds microscope slides coated in dilute petroleum jelly. Previous work by my graduate student, Meg Sanders, has shown similar traps are very effective at capturing HWA individuals and other HWA material. Using these traps, we are using quantitative polymerase chain reaction (qPCR) to monitor for the presence of HWA in high-risk areas (see HWA monitoring page). We are also evaluating whether these traps can detect the presence of other small forest pests, like the nematode the causes beech leaf disease.
eDNA and Ecosystem Changes
Hemlocks are foundation species that disproportionally regulate microclimates it inhabits. Significant loss of hemlocks in an ecosystem can drive large-scale, ecosystem changes that include changes in species abundance, stream temperature, soil chemistry, carbon storage distribution, and water yield. As hemlocks begin to decline in Michigan, it is important to understand the impact this will have on coastal dunes forests and how any impacts may be mitigated. Because our traps not only collect HWA, but other DNA that is present in the environment, we are using them to track changes in community composition in infested areas. This information can be used to understand how changes in community composition could alter ecosystem functions. This will help us begin to understand the impact that HWA-driven hemlock loss will have on our coastal forest ecosystems.
Portions of this work have been funded by a Special Technology Development Grant from the US Department of Agriculture, US Forestry Service and Michigan Invasive Species Grant.
