eDNA extraction from passive collection materials
All cellulose ester materials, as well as the nylon bags, were cut or flash frozen (-80ºC) and crushed into small pieces that were placed in a 2 mL Eppendorf tube in preparation for extraction. All other materials were placed directly into a 2mL Eppendorf tube as is for extraction. Total nucleic acid was extracted from all materials in the same fashion using a DNeasy Blood and Tissue Kit (Qiagen; Venlo, Netherlands), with an additional 40 µL of Proteinase K used during a three-hour digestion period at 56°C on rotation (300 rpm). DNA was eluted into 200 µL AE buffer. All extractions took place in a dedicated DNA extraction laboratory using a QIAcube (Qiagen; Venlo, Netherlands), where benches and equipment were routinely bleached and cleaned.