The impact of salamander predation on Collembola abundance

We examined the role of the red-backed salamander, Plethodon cinereus, in c ontrolling springtail (Collembola) abundance in a temperate deciduous fores t. Salamander abundance was manipulated in paired, replicated held enclosur es during Fall 1993 and spring 1994, such that each cage either had four or zero salamanders m(-2). After four weeks we sampled arthropod abundance wi th pitfall traps. The abundance of arthropods was compared using two-way MA NOVA (treatments = salamanders and season), followed by univariate tests fo r each taxon. The effects of salamanders on arthropods was not significant (Wilks' lambda = 0.76, P = 0.6), but Collembola were significantly more abu ndant in the presence of salamanders. Season had a significant effect on ar thropod abundance (Wilks' lambda = 0.13, P < 0.0001); beetles, crickets, mi llipedes, and mites were more abundant in the fall, and Collembola were mor e abundant in the spring. Stomach analysis of salamanders showed that ants were their main prey item, and Collembola were not among the prey taken. We hypothesize that salamanders indirectly enhanced Collembola abundance by p reying upon their invertebrate predators.