Energy Flow and Nutrient Cycling in Salamander Populations in the Hubbard Brook Experimental Forest, New Hampshire

Abstract

Energy flow through salamander populations in the Hubbard Brook Ecosystem is about 11,000 kcal/ha°yr (= 46,000 kJ/ha°yr). This is °0.02% of the net primary productivity, and is °20% of the energy flow through bird and mammal populations. Salamanders are efficient (60%) at converting ingested energy into new tissue and produce more new tissue annually than do bird populations. Salamanders are insignificant agents as “sinks” for nutrients or as agents for nutrient cycling in the ecosystem. Sodium is the possible exception, as an amount equivalent to > 8% of the Na in annual litter fall passes through salamander populations; all other nutrients (Ca, Mg, K, P, N, S, and Zn) are < 1%. Calicium content of salamanders is > that of most of their invertebrate prey. There is some evidence that invertebrates rich in Ca content, such as snails and mites, are necessary components of the diet of salamanders. Salamander tissue is higher in protein content than that of birds and mammals and represents a source of high—quality energy for potential predators. Salamanders have restricted home ranges and are not significant agents in the movement of nutrients into or out of the system.