From DNA to ecosystems – The promise of biological archives for biodiversity monitoring

Detecting the imprints of global environmental change on biological communities is a major challenge for current ecological research. The analysis of the effects of environmental change requires standardized and replicated time series data, which is lacking for most ecosystems and taxa. This lack of community level time series data has become particularly evident with recent reports on global insect decline. Natural history collections are currently receiving attention for their potential to document environmental change, but they usually do not provide community level data. Considering this background, new approaches and data sources are urgently needed to understand historical community change in the Anthropocene. Recent developments in high throughput DNA metabarcoding hold great promise to provide the needed data. The analysis of environmental DNA (eDNA), DNA traces left by organisms in their environment, has particularly revolutionized biodiversity research. eDNA is preserved in many biological archives, making it possible to trace taxonomic changes at unprecedented temporal detail. In my presentation, I will give an overview of our work using eDNA analysis in a large biological archive,  the German Environmental Specimen Bank (ESB). In the past three decades, the ESB has compiled biotic samples from various ecosystems of Germany, including marine, limnic and terrestrial habitats. The samples are collected according to highly standardized protocols and permanently stored at ultra-low temperatures, which makes them an ideal source of historical eDNA. I will first highlight our recent work on the reconstruction of temporal changes in German forest insect communities from eDNA traces associated with ESB leaf samples. Then I will discuss other sources of community level eDNA in marine, limnic and terrestrial samples of the ESB and show preliminary results on community change in different taxonomic groups across the tree of life in the past 30 years.