The California Red-legged Frog (Rana draytonii) is a federally threatened species that is declining in its range. Additionally, other Amphibians are decreasing in their distribution, and researchers attribute these declines to the occurrence of exotic predators. For nearly 150 years, the introduction of non-native fish into California livestock ponds has been prevalent. The impact of these releases has been damaging to native frogs. Pond restoration efforts aimed at eradicating non-native fish can reverse this trend by improving habitat conditions that support recovery goals for the California Red-legged Frog. Following the removal of Largemouth Bass (Micropterus salmoides) and Bluegill (Lepomis macrochirus) from a permanent livestock pond at Pleasanton Ridge Regional Park in the fall of 2022, the location started supporting native amphibians the following spring. For the first time since 2016, when systematic annual survey began, adults and larvae Pacific Chorus Frog (Pseudacris regilla) and California Newt (Taricha torosa) started inhabiting the pond (2023 to 2025). Adult California Red-legged Frogs colonized the site, one year later (2024 to 2025). This new site-specific information on California Red-legged Frog and native Amphibian response to exotic fish removal in a central California rangeland will inform recovery efforts designed to preserve and manage habitat for this threatened species.

David (AKA “DOC QUACK”) Riensche, a Certified Wildlife Biologist, and a Certified Senior Ecologist, is a Wildlife Biologist II for the East Bay Regional Park District where he has worked for over 37 years. For 28 years he has been a member of the Biology Department faculty at Las Positas College, where he teaches courses in biology, ecology, and vertebrate natural history. He is a recipient of The National Association for Interpretation (Region 9) – Outstanding Field Naturalist Award. David holds advanced degrees in both Natural Resource Management and Environmental Education, and an undergraduate degree in Biology (Wildlife). His current wildlife research and habitat restoration efforts are diverse, focusing on the following species and groups: California Least Tern, Western Snowy Plover, Black Skimmer, Forster’s Tern, Western and Clark’s Grebes, Bald Eagle, Ridgway’s Rail, California Black Rail, Burrowing Owl, California Red-legged Frog, California Tiger Salamander, Western Pond Turtle, Salt Marsh Harvest Mouse, San Francisco Dusky-footed Woodrat, Bats, Fairly Shrimp, Central California grassland lizards and small mammals, riparian and oak woodland breeding bird community structure, shorebird nesting population studies, upland gamebirds and waterfowl management