MONITORING, UNDERSTANDING AND PROTECTING FRESHWATER BIODIVERSITY IN NATURAL, ARTIFICIAL AND MODIFIED WATERWAYS IN BOREAL FORESTS USING DNA METABARCODING

Man-made ditches, modified waterways, and small natural streams make up over 90 % of the total length of running waters in Sweden. Millions of kilometers of these small waterways are exposed to pressures from forestry, including insufficient riparian buffers along modified waterways and the cleaning of drainage ditches. Such practices pose major threats to aquatic biodiversity, yet we currently lack the capacity to predict biodiversity responses, as these systems are largely overlooked in monitoring programs. Using DNA metabarcoding targeting diatoms and bacteria sampled from multiple substrates at 56 sites across Sweden, we explored biodiversity patterns along a gradient from natural streams to man-made ditches, with and without recent forestry pressure. We can, for the first time, provide a snapshot of microbial biodiversity in these understudied systems. Our results suggest that recent forest harvesting surrounding waterways influences habitat conditions – especially light availability and temperature – more strongly than whether the system is natural or man-made. Interestingly, geographic region emerged as a stronger predictor of diatom community composition compared to both waterway type and recent forestry disturbance, suggesting that the biodiversity values of natural and man-made waterways may be more similar to each other than expected. Our ongoing work aims to develop a cost-efficient and scalable field and laboratory protocol and provide an eDNA-based diatom index tailored for small boreal forest waterways to assess their ecological status.

Presentation Preference: Standard Oral (12 Minutes)

Primary Presenter: Cedric Bagheri Åkermark, Swedish University of Agricultural Sciences (cedric.akermark@slu.se)

Authors:

Cedric Bagheri Åkermark, Swedish University of Agricultural Sciences  (cedric.akermark@slu.se)

Maria Kahlert, Swedish University of Agricultural Sciences  (maria.kahlert@slu.se)

Brendan McKie, Swedish University of Agricultural Sciences  (brendan.mckie@slu.se)

Theresa Lumpi, Swedish University of Agricultural Sciences  (theresa.lumpi@slu.se)

Anna Székely, Swedish University of Agricultural Sciences  (anna.szekely@slu.se)

Eliza Maher Hasselquist, Swedish University of Agricultural Sciences  (eliza.hasselquist@slu.se)

Lenka Kuglerová, Swedish University of Agricultural Sciences  (lenka.kuglerova@slu.se)