Amphibian monitoring protocol (version 2.0): Great Lakes Inventory and Monitoring Network

Casper, Gary; Beever, Erik; Gafvert, Ulf; Nadeau, Stefanie

The National Park Service’s (NPS) Great Lakes Inventory and Monitoring Network (GLKN) has developed a prioritized list of indicators, termed “Vital Signs”, for monitoring long-term ecosystem health in NPS units in the Great Lakes ecoregion. This amphibian monitoring protocol is one of several protocols that GLKN is currently implementing is seven NPS parks: Apostle Islands National Lakeshore, Grand Portage National Monument, Indiana Dunes National Lakes Shore, Isle Royale National Park, Mississippi National River and Recreation Area, Pictured Rocks National Lakeshore, and Sleeping Bear Dunes National Lakeshore. Guiding principles for selecting this protocol’s survey methods were: 1) maximizing detection probabilities, 2) minimizing cost, 3) practicality (in terms of non-experts being able to conduct surveys or collect data with minimal training and practical logistics), and 4) potential for partnering (in terms of using standard methods in widespread use to allow for data sharing)––all while meeting rigorous scientific standards for statistical power. The program collects digital acoustic data utilizing automated recording systems deployed at wetlands within each park, supplemented with temperature loggers. This equipment is typically deployed in early spring, checked on once in late spring, and retrieved in August. Digital data are then archived and sent for analysis. The analysis consists of a series of steps designed to detect every species present at each site in each year with minimal false absences and no false positives. The latter condition is important for accurate occupancy trend analyses. In brief, the analysis steps are: 1. Examine and organize annual data with quality control reporting. 2. Run acoustic samples (ca. 150/site/year) through software developed for automated species recognition. 3. Proof the auto-classification results to eliminate false positives for each sampling site. 4. Independently select 30 samples from the same dataset for manual surveys. 5. Manually survey these 30 samples, with an expert observer scoring each species present in each sample by visually and acoustically examining each acoustic signature encountered. 6. Have a second observer verify manual results. 7. Report on results. 8. Periodically (ca. every 5 years) run results through occupancy models to analyze trends. This system provides an economically feasible methodology for the GLKN to track frog and toad occupancy trends within the region, and can be built upon incrementally to provide greater coverage as future needs dictate. It also allows for pooling of data with other regions or partners to expand analysis of natural resources monitoring, and the methodology can be readily developed further to monitor other wildlife that communicate acoustically (i.e., birds). Currently the program is monitoring 66 sites in seven parks, and analyzes approximately 2 TB of data annually.

Amphibian monitoring protocol (version 2.0): Great Lakes Inventory and Monitoring Network

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