Using eDNA to understand predator-prey interactions influenced by invasive species

Area of Science:

• Ecology
• Conservation Biology
• Environmental Science

Background:

• Invasive species disrupt ecosystems by altering prey population dynamics.
• Assessing predator-prey interactions is challenging, especially for elusive species.
• Environmental DNA (eDNA) analysis offers a novel approach to detect species presence and interactions.

Purpose of the Study:

• To evaluate the effectiveness of eDNA analysis in assessing predator-prey interactions between invasive fishes and native amphibians.
• To investigate the impact of invasive fishes (Lepomis gibbosus, Pseudorasbora parva) on amphibian populations (Triturus cristatus, Pelobates fuscus).

Main Methods:

• Quantitative eDNA analysis using species-specific TaqMan assays.
• Water samples collected from 89 sites across 31 ponds over three months in Germany.
• Monte-Carlo statistical tests to analyze eDNA concentration relationships.

Main Results:

• A significant negative correlation was found between the eDNA concentrations of invasive fish predators and amphibian prey.
• eDNA data supported the hypothesis that invasive fishes are a contributing factor to local amphibian declines.
• The study demonstrated the utility of eDNA for detecting ecological interactions in aquatic ecosystems.

Conclusions:

• eDNA analysis is a powerful tool for understanding predator-prey dynamics, particularly for difficult-to-monitor species.
• Invasive fishes pose a threat to native amphibian populations, necessitating targeted conservation and management strategies.
• This research underscores the importance of eDNA in guiding effective conservation actions for vulnerable species.