Salamanders Are More Than a Snack in Forest Ecosystems

Salamanders are tricky to spot and certainly even harder to keep track of. That's why salamander populations have largely been left up to speculation. However, new research suggests that they are actually very prevalent, and play a significant role in the food chain of whole-forest ecosystems.

"Using the latest research methods, we calculated the population size of Southern Redback Salamanders in Ozark Forests and their value as a food source," researcher Ray Semlitsch, at the University of Missouri, said in a recent release. "We found that 1.88 billion salamanders inhabit one district of the Mark Twain National Forest alone, which is roughly 1,400 metric tons of biomass. For comparison, that's equivalent to the biomass found in most whitetail deer in that region!"

These results and more were detailed in a study recently published in the Canadian Journal of Zoology.

Back in the 1970s, ecologists fist stumbled upon evidence that salamanders could represent a major source of biomass, or food, for an entire forest. They determined this after painstakingly collecting the creatures for weeks or even months from the forest floor. However, experts now understand that the majority of these creatures spend their time hiding underground.

For this latest study, researchers instead ran brief surveys of the forest floor over the course of two years at random times. Statistical modeling helped them determine how many salamanders were likely to be missed, and produced a more thorough assessment of salamander population density.

"Our abundance models also take into account environmental factors," Semlitsch said. "Factors such as date of collection, time since last rainfall, slope of the terrain and forest canopy cover are plugged into the model to help predict variation in the surface population over time; that's what makes our model so powerful. The hidden biodiversity of amphibians is something we don't generally consider; we forget that salamanders are nocturnal and mostly unobserved. Therefore, I think most will be amazed at the quantities of food out there that we just don't see."

However, if salamanders are indeed a common and important source of biomass to any forest ecology, that might mean many ecosystems are even more vulnerable to new diseases than once thought.

Fatal fungal infections of Batrachochytrium salamandrivorans are sweeping through salamander populations, for example, affecting a whopping 520 amphibian species worldwide so far.

"If even a few of these animals have the fungus, it's a question of when, not if, this fungus reaches North America," researcher Carly Muletz warned in a statement earlier this year.