National Capital Parks–East Amphibian Monitoring, 2023

Marbled salamander (Ambystoma opacum). NPS / L. Beimfohr.

At least 12 amphibian species

Field teams monitor wetland pools in the parks of National Capital Parks–East, recording which amphibians they find where. Across all sites, that gives each species' occupancy — the share of sites where it lives. The question: is occupancy changing?

Some species live outside the monitored wetlands — red-backed salamanders on land, burrowing eastern spadefoot toads. They may live in the parks, but the monitoring isn't designed to find them; incidental sightings are recorded but left out of the analysis.

Wetland amphibians in 2023

• Three wetland species were seen in 2023; 12 since monitoring began in these parks in 2016.
• Fewer visits: usually two a year; in 2023 crews visited 24 wetlands once, in April.
• Most abundant: southern leopard frogs (four adults), then spring peepers and wood frogs — each found at one wetland.

Figure 1. Occupancy probability by species in wetland pools at National Capital Parks–East. NPS.

How to read the figure

• Dark gray bars: occupancy from raw sightings.
• Black dots and lines: estimated occupancy, filling gaps because amphibians hide well and crews count fewer than are present.
• Light gray bands: 95% credible intervals.
• "Gray treefrog complex" and "Toad complex": closely related species grouped together.
• "Trend" box: a number and color for the estimated trend — blue positive, white neutral, yellow slightly negative, red negative; the parentheses give the 95% credible interval.
• Species are in alphabetical order by common name.

Spotted salamander (Ambystoma maculatum). NPS / C. Shafer.

These data are preliminary and may be revised. They have not received final approval by the U.S. Geological Survey, and are provided on the condition that neither USGS nor the U.S. Government is liable for damages from their use.

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Sources

Based on "NCP East Amphibian Monitoring 2023," part of the series Amphibian Monitoring in the National Capital Region, National Park Service; a work of the United States government in the public domain.