You are here:
PROJECTED POPULATION-LEVEL EFFECTS OF THIOBENCARB EXPOSURE ON THE MYSID, AMERICAMYSIS BAHIA, AND EXTINCTION PROBABILITY IN A CONCENTRATION-DECAY EXPOSURE SYSTEM
Citation:
Raimondo, S AND C L. McKenney Jr. PROJECTED POPULATION-LEVEL EFFECTS OF THIOBENCARB EXPOSURE ON THE MYSID, AMERICAMYSIS BAHIA, AND EXTINCTION PROBABILITY IN A CONCENTRATION-DECAY EXPOSURE SYSTEM. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 24:564-572, (2005).
Impact/Purpose:
to estimate population-level effects from pesticide exposures
Description:
Population-level effects of the mysid, Americamysis bahia, exposed to varying thiobencarb concentrations were estimated using stage-structured matrix models. A deterministic density-independent matrix model estimated the decrease in population growth rate, l, with increasing thiobencarb concentration. An elasticity analysis determined that survival of middle stages provided the largest contribution to l. Decomposing the effects of l in terms of changes in the matrix components determined that reduced reproduction had a large influence on population dynamics at lower thiobencarb concentrations, whereas reduced survivorship had the largest impact on populations at higher concentrations. A simulation model of a concentration-decay system was developed to demonstrate the importance of integrating chemical half-life and management practices in determining population viability. In this model, mysids were originally exposed to a high thiobencarb concentration (300 ?g/L) that decayed an order of magnitude in the number of mysid generations corresponding thiobencarb half-life values under three different exposure regimes. Environmental stochasticity was added to the model to estimate the cumulative extinction probability (CEP) of mysids exposed to fluctuating concentrations of thiobencarb in random environments. The CEP increased with thiobencarb half-life, stochasticity, and concentration present at the time of a new exposure. The model demonstrated the expansion of population projection models in determining the ecological impact of a population exposed to pesticides.