Antietam Amphibian Monitoring 2023

American toad (Anaxyrus americanus)

NPS / C. Shafer

Home to at least five amphibian species!

We monitor wetlands at Antietam National Battlefield. Field teams visit wetlands and streams, recording which amphibian species they observe and in which sites. Looking across all sites in a park, they generate a measure of species “occupancy,” that shows what proportion of sites are occupied by a particular species.

We want to know, “is there a change in occupancy over time?”

A few amphibian species are found outside of the wetland environments that we monitor (like terrestrial, red-backed salamanders and burrowing, eastern spadefoot toads). These species may live in the park, but our monitoring is not designed to document them. While we do record incidental sightings, they are excluded from the data analysis.

Wetland amphibians: 2023 Findings

In 2023, we observed two wetland species. We have observed five total wetland species at Antietam since monitoring began in 2021:

• American toad
• American Fowler's toad
• northern green frog
• pickerel frog
• northern dusky salamander.

Lower numbers in 2023 are the result of fewer visits to monitoring sites. Usually there are two each year. Field crews visited seven wetlands once in May of 2023. Two of the nine previously mapped wetland sites were removed from the sampling list, because their location fell outside the park boundary.

American toads were the most abundant amphibian detected (roughly 30,000 larvae). Each species was detected at only one wetland.

Occupancy plots will be provided once we have a few years of replicate survey visits.

These data are preliminary or provisional and are subject to revision. They are being provided to meet the need for timely best science. The data have not received final approval by the U.S. Geological Survey (USGS) and are provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the data.