Red-Backed Salamanders at Valley Forge: Coverboard Study, 2013–2023

The two color phases: lead-backed (left) and red-backed (right), which differ in behavior and physiology. NPS photo / T. Henckel.

The eastern red-backed salamander

Plethodon cinereus is a small, land-dwelling salamander of northeastern North America.

• Home: moist forest floors, under rocks and logs; it's abundant.
• Breathing: it has no lungs and takes in oxygen through its skin.
• Habits: nocturnal, coming out on cool nights to eat mostly insects.
• Two looks: the red-backed phase has a red stripe down its back; the lead-backed phase doesn't.

Why study it

Valley Forge National Historical Park tracks red-backed salamander populations in its forests. Their trends show how healthy the ecosystem is as the forest responds to fewer deer and other management and environmental changes.

Coverboards

Lifting a coverboard to look for salamanders. NPS photo / M. Lefevre-Levy.

The study uses arrays of wooden boards laid evenly spaced on the forest floor. They give salamanders a cool, damp place to spend the warmer daytime hours — and let biologists count them without tearing up their habitat.

The park also compares its two main forest types: oak (Quercus), with drier floors, and tulip poplar (Liriodendron).

A red-backed salamander. NPS photo / T. Henckel.

Results, 2013 to 2023

• Numbers: about 23 salamanders a day, varying a little with temperature and rain.
• Color phases: red-backs outnumbered lead-backs about 1.7 to 1.
• Trend: the average per visit has varied since 2013, with no clear trend overall.
• Forest type: no significant difference between oak and tulip poplar forests.

Average salamanders found per visit, each year 2013–2023. NPS graphic.

How you can help

Follow Leave No Trace: please don't turn over rocks and logs looking for salamanders — it destroys their habitat.

Sources

Based on "Salamander Coverboard Study Resource Brief 2024," Valley Forge National Historical Park, National Park Service; a work of the United States government in the public domain. Natural resource management staff: Kate Jensen, Natural Resource Manager; Marta Lefevre-Levy, Ecologist; Ashley Kroon, Biological Science Technician. Prepared by August Blackman, natural resource management intern, 2023–2024.