At population densities of roughly 10,000 per hectare (more than 4,000 per acre) the red-backed salamander is by far the most abundant vertebrate on the Holt Research Forest. Given their abundance, habitat (forest floor litter), and diet (litter invertebrates), it is likely that they play a large role in forest ecology. For example, redbacks slow the rate of litter decomposition by preying on the invertebrates that shred leaf litter.
From 1983 to 1986 we conducted surveys designed to estimate population densities of redbacks. In 1987 we switched methodology to obtain a population index. Interpreting these data is complicated because the number of salamanders detected is very sensitive to rainfall patterns: more salamanders are near the surface during usually wet months such as May and during wet years. Nevertheless, redbacked salamander populations are probably reduced in the harvested portion of the forest compared to the control side. This topic will require further research because it is possible, albeit unlikely, that redback counts on the harvested area are not diminished; they may merely be living deeper in the soil and thus are harder to detect.