Amphibian monitoring in hardwood forests: Optimizing methods for contaminant‐based compensatory restorations.

This article evaluates amphibian monitoring techniques at four restored bottomland hardwood forest sites in northeastern Indiana, USA, focusing on their effectiveness, cost, and suitability for restoration monitoring under the U.S. Department of the Interior’s Natural Resource Damage Assessment and Restoration (NRDAR) Program. Thirteen amphibian species were detected, including two Indiana Species of Special Concern: northern leopard frogs (Lithobates pipiens) and Blanchard's cricket frogs (Acris blanchardi). Among four methods tested—automated recording units (ARUs), diurnal visual encounter surveys (VES), nocturnal transect surveys, and amphibian rapid assessments (RAs)—RAs yielded the highest species richness and catch per unit effort at the lowest cost, while ARUs provided extensive acoustic data but required greater investment and had limitations detecting salamanders. Modeling of ARU data indicated that increasing the number of nights sampled was the most effective way to maximize species detection, offering guidance for efficient acoustic survey design in restoration contexts.