Biology subjects

Koschorrek, J.

Publications and source records attributed to Koschorrek, J..

3 recordsLinked to original sources

bioRxiv2026

eDNA metabarcoding provides scalable and continuous biodiversity monitoring across the tree of life

Environmental DNA (eDNA) metabarcoding has the potential to substantially expand our knowledge of global biodiversity beyond that provided by conventional approaches. However, the degree to which eDNA data provides real ecological insight, rather than primarily reflecting environmental factors that affect eDNA shedding and degradation, remains unclear. Additional uncertainties arise in terms of cost-effectiveness and whether the price is worth any extra biodiversity information that is gleaned. Here, we established a high-resolution, bi-weekly eDNA time-series in Germany across aquatic and riparian habitats to quantify seasonal biodiversity dynamics, to relate eDNA to different potential environmental drivers, and to parametrize cost estimates. Over one year, eDNA metabarcoding detected more than 1,000 species across multiple trophic levels and primarily revealed real, taxon-specific seasonal patterns, in addition to some relationships to water temperature, discharge, and conductivity. Compared to historical records dating back to 1891, year-round eDNA monitoring increased reported species numbers by 2.4-fold for invertebrates, 2.2-fold for mammals, 1.7-fold for diatoms, 1.2-fold for fish and lamprey, and 1.03-fold for birds. Cumulative biodiversity estimates increased strongly with sampling frequency, demonstrating the value of eDNA for high-frequency time-series monitoring. Moreover, eDNA monitoring was highly cost-effective, providing more than twice the biodiversity information of many conventional surveys for one-sixth the cost, enabling scalable, high-resolution freshwater biodiversity assessments.

ecology↗

bioRxiv2025

Unraveling long-term trends and drivers of fish biodiversity change using environmental DNA metabarcoding of archived samples

AbstractLong-term biodiversity data are critical for assessing, understanding, and predicting ecosystem change globally, but are often limited by their availability. We present the longest eDNA metabarcoding time series for freshwater fishes based on archived suspended particulate matter (SPM) from Germanys Environmental Specimen Bank, covering 17 years (2005-2021) across six major European river systems (Rhine, Danube, Elbe, and their tributaries). From 211 annual samples collected according to highly standardized procedures at 13 sites, we detected 63 fish and lamprey species and traced their spatio-temporal trajectories. eDNA metabarcoding captured significantly declining trends at multiple sites with no recoveries. Common and sensitive species declined at nearly half of sites while invasive species spread. Site occupancy and relative read abundance trends were correlated, providing semi-quantitative indicators. Alpha and beta diversity shifted over time and Bayesian hierarchical models revealed that 19% of species showed significant declines in relative read abundance. The eDNA-derived trends showed strong concordance with long-term regulatory fish monitoring data, validating the patterns across methodological approaches. Random forest models and multivariate analyses identified multiple anthropogenic pollutants, measured from the same SPM samples, as drivers of biodiversity patterns. Pesticides, heavy metals, temperature, and fine sediment negatively affected species richness, with site-specific stressor combinations explaining 29% of community variation. Our results demonstrate that archived SPM, originally collected for chemical monitoring, provides a reliable, dual-purpose monitoring matrix integrating pollution and biodiversity trend assessments simultaneously. This approach enables holistic monitoring of global freshwater ecosystem change and can provide an early warning framework supporting evidence-based environmental management.

ecology↗

bioRxiv2022

Environmental DNA from archived leaves reveals widespread temporal turnover and biotic homogenization in forest arthropod communities

A major limitation of current reports on insect declines is the lack of standardized, long-term, and taxonomically broad time series. Here, we demonstrate the utility of environmental DNA from archived leaf material to characterize plant-associated arthropod communities. We base our work on several multi-decadal leaf time series from tree canopies in four land use types, which were sampled as part of a long-term environmental monitoring program across Germany. Using these highly standardized and well-preserved samples, we analyze temporal changes in communities of several thousand arthropod species belonging to 23 orders using metabarcoding and quantitative PCR. Our data do not support widespread declines of -diversity or genetic variation within sites. Instead, we find a gradual community turnover, which results in temporal and spatial biotic homogenization, across all land use types and all arthropod orders. Our results suggest that insect decline is more complex than mere -diversity loss, but can be driven by {beta}-diversity decay across space and time.

ecology↗