Competitive and Predatory Interactions in Natural and Experimental Populations of Notophthalmus viridescens dorsalis and Ambystoma tigrinum

Abstract

In natural ponds, adult N. viridescens prey on developing eggs of A. tigrinum. Predation by Notophthalmus was strong enough to exclude larval Ambystoma from 1 natural pond. Experiments conducted in artificial ponds demonstrated that the presence of Notophthalmus depressed mean mass at metamorphosis of surviving Ambystoma larvae. The presence of large Ambystoma larvae depressed eft production by Notophthalmus. Variation in density of adult Notophthalmus was not related to growth of adults and larvae, or eft production. Adult survival was depressed at high levels of adult density. Growth of adults and larvae was negatively correlated with larval density, suggesting competition between subpopulations in these 2 phases of the newt life cycle.