Meeting Abstract

108.6  Tuesday, Jan. 7 09:30  The effects of stress on nutrient stoichiometry in larval amphibians and the resulting influence on ecosystem processes KIRSCHMAN, L.J.*; FRITZ, K.F; WHILES, M.R.; WARNE, R.W.; Southern Illinois University; Southern Illinois University; Southern Illinois University; Southern Illinois University l.j.kirschman@gmail.com

The effects of environmental stressors, particularly low-level, chronic stressors, are not always apparent in populations or communities. A population may be robust and appear healthy, but the majority of individuals may be living in altered physiological states that influence metabolic and nutrient processes. Stressed populations may also affect their environment through altered patterns of nitrogen excretion and nutrient transfers to other trophic levels. These dynamics may substantially alter nutrient availability in aquatic ecosystems, potentially affecting functions such as decomposition and primary production. Amphibian larvae, which are often abundant in freshwater habitats, can operate at multiple trophic levels and significantly influence nutrient cycling. Investigating how environmental stressors may alter the physiological state of these abundant consumers is central to understanding how they can influence ecosystem processes. We used mesocosm experiments to examine the effects of experimentally induced physiological stress, induced through chronic exposure to exogenous cortiscosterone or invertebrate predator cues, on the nutrient stoichiometry of wood frog larvae (Rana sylvatica) tissues and excretion. We also examined the effects of tadpoles on leaf litter decomposition and microbial respiration.