Aquatic Biodiversity Assessment in Alpine Lakes — A Season with AcquaDecode
Three lakes. Twelve sampling sessions. Zero species capture required. A conservation team in the Swiss Alps used AcquaDecode to conduct a comprehensive aquatic biodiversity survey entirely from water samples.
Environmental DNA monitoring is not a new concept. The idea that organisms shed genetic material into their surroundings — skin cells, mucus, faeces — and that this material can be detected and identified from environmental samples has been established science for over a decade. What has changed is the accessibility of the technology.
This case study documents a season-long aquatic biodiversity survey conducted at three Alpine lakes in canton Graubünden, using AcquaDecode as the primary monitoring tool.
Why eDNA for Alpine lakes?
Traditional aquatic biodiversity assessment relies on physical sampling — electrofishing, net surveys, underwater observation. In Alpine lake ecosystems, these methods are logistically demanding, seasonally constrained, and in some cases prohibited for sensitive species. eDNA sampling requires only a water sample, collected from the shoreline or from a boat, with no disturbance to the ecosystem.
The survey protocol
At each of the three lakes, water samples were collected at three depth profiles and two shoreline stations during each monitoring session, for a total of 36 samples per session across the season. The AcquaDecode unit was transported by field vehicle to each site and operated directly from the shoreline. No cold-chain sample preservation was required.
Key findings
The survey detected 23 distinct aquatic species across the three lakes, including six fish species, four amphibian species, and a range of macroinvertebrates. One finding stands out: at Lake B, the eDNA analysis detected a signal consistent with the presence of brook trout (Salvelinus fontinalis), an invasive species not previously recorded in that water body. A follow-up targeted survey confirmed the presence of a small but established population.
The early detection of this invasive species — before it reached a population level visible through conventional sampling — represents exactly the kind of conservation value that eDNA monitoring is designed to provide.
Seasonal patterns
Across the monitoring season, eDNA signal strength for several species showed clear seasonal variation, consistent with known reproductive and behavioural cycles. These patterns were detectable without any physical species observation.
Key figures
- 3 lakes · 12 sessions · 36 samples per session
- 23 aquatic species detected
- 1 invasive species identified before visual detection
- 0 fish captures required
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