Comparing eDNA and Transect Methods for Aquatic Biodiversity Assessment in Lakes and Ponds

Area of Science:

• Ecology
• Molecular Biology
• Conservation Science

Background:

• Molecular methods like eDNA metabarcoding are increasingly used for biodiversity monitoring.
• Established applications are limited to certain taxonomic groups, necessitating research into method strengths and weaknesses.
• Reliable application of eDNA requires understanding its performance, especially for underrepresented groups.

Purpose of the Study:

• To compare the effectiveness of eDNA metabarcoding and traditional survey methods for amphibians and Odonata.
• To assess the strengths and weaknesses of eDNA metabarcoding for different taxonomic groups in biodiversity monitoring.
• To evaluate the complementarity of eDNA metabarcoding and traditional methods for ecological assessments.

Main Methods:

• eDNA metabarcoding and traditional transect walks were conducted on 56 plots across 38 water bodies.
• Amphibians were assessed via visual encounters, dip netting, and acoustic detection.
• Odonata were assessed using exuviae (shed skins).

Main Results:

• Both methods detected 8/11 amphibian species; eDNA identified 3 additional species.
• Amphibian species richness per plot was similar, but eDNA metabarcoding showed higher detection probabilities.
• For Odonata, 10/29 species were detected by both methods, while 19 were found only via exuviae; exuviae yielded higher species numbers per plot.

Conclusions:

• eDNA metabarcoding is efficient for amphibian monitoring, complementing traditional methods and offering a suitable protocol.
• eDNA metabarcoding showed significant gaps for Odonata, highlighting the need for protocol optimization for certain ecological communities.
• The study underscores the varying performance of eDNA metabarcoding across taxa, impacting its reliability for comprehensive biodiversity assessments.