Print PagePlant detritus often provides >90% of the energy and materials in aquatic food webs, yet few studies have tested the impact of plant detrital traits on larval amphibian growth and survival. In order to explore this topic, we reared Anaxyrus americanus (American Toad) larvae individually in 1 L outdoor mesocosms under 27 plan litter treatments. The treatments included 15 native species treatments, 9 non-native species treatments, and four diversity treatments (1, 3, 6, 12 species) (30 replicates/treatment for a total N =840). From 24 May to 12 August 2010 we monitored larval survival, development rate, and size at metamorphosis (weight and snout-vent length). We also collected data on the abiotic condition of mesocosms (pH, dissolved oxygen, temperature, and conductance) and litter stoichiometry (C, N, P and lignin levels). Based on the findings of previous studies, we hypothesized that larvae would show higher survival and develop faster when reared with native species litter and their performance would improve with increasing litter diversity.
Results/Conclusions
Survival, development, and size at metamorphosis were significantly different among treatments but neither plant origin nor diversity were important in explaining these effects. Both weight and SVL at metamorphosis were significantly negatively correlated with increasing C:N and C:P ratios. Our results indicate that differences in plant traits are more important in explaining the performance of larval A. americanus tadpoles than plant origin or litter species richness. These conclusions have implications for current wetland restoration: If exposure to certain plant species contributes to elevated stress in developing tadpoles, additive or synergistic effects with other stressors (predators, competitors, pesticides, parasites, diseases, UV-radiation or elevated temperature) may further affect already-dwindling amphibian populations.
