Stochastic models for toxicant-stressed populations.

We obtain conditions for the existence of an invariant distribution on (0, infinity) for stochastic growth models of Ito type. We interpret the results in the case where the intrinsic growth rate is adjusted to account for the impact of a toxicant on the population. Comparisons with related results for ODE models by Hallam et al. are given, and consequences of taking the Stratonovich interpretation for the stochastic models are mentioned.