Hydrological Connectivity Enhances Fish Biodiversity in Amazonian Mining Ponds: Insights From eDNA and Traditional...

Area of Science:

• Ecology
• Environmental Science
• Conservation Biology

Background:

• Artisanal and small-scale gold mining (ASGM) in Peru's Madre de Dios region has created extensive mining ponds.
• Post-mining ecological recovery, especially fish biodiversity, in these novel wetland systems is understudied.

Purpose of the Study:

• To evaluate fish community richness and composition in ASGM mining ponds.
• To compare traditional sampling with environmental DNA (eDNA) methods for biodiversity assessment.
• To identify factors influencing fish recolonization in post-mining aquatic environments.

Main Methods:

• Fish communities were assessed in mining ponds of varying dimensions, ages, and physicochemical properties.
• Traditional collection-based methods and eDNA (12S and COI markers) were used for biodiversity inventory.
• ASGM waterbodies were compared with pristine oxbow lakes, analyzing hydrological connectivity.

Main Results:

• eDNA methods, particularly the 12S marker, detected higher fish richness than traditional methods.
• Hydrological pulse flood connectivity was the primary predictor of species richness in mining ponds.
• Fish communities in pulse-flooded ponds showed greater similarity to pristine oxbow lakes.

Conclusions:

• Environmental DNA is a valuable tool for assessing fish biodiversity in post-mining landscapes.
• Enhancing hydrological connectivity is crucial for accelerating ecological recovery in abandoned mining ponds.
• Restoration strategies should prioritize improving aquatic connectivity to support fish recolonization.