Population persistence in rivers.
SPEIRS, D.C.* and W.S.C.GURNEY
University of Strathclyde, Glasgow, Scotland 1
Many organisms inhabiting streams and rivers are continually subjected to downstream drift, and when this is the only transport process population extinction is inevitable. Using analytical and numerical models representing a range of hydrodynamic scenarios, we demonstrate how the action of random dispersal can permit persistence in such advective environments by allowing a proportion of the population to reproduce close to their natal location. We establish convenient approximate analytic conditions for diffusion-mediated persistence in benthic and planktonic populations. The approximations are supported by numerical simulations which also indicate the robustness of the results to variations in hydrodynamics. Estimating parameters from published field studies, we show that the persistence of various aquatic invertebrates may be diffusively mediated in situations where horizontal dispersal is high and advection is relatively low.
Keywords: population dynamics, drift paradox, advective environments
This abstract is being presented at: 9:30 AM in session:
Oral Session #39: Theoretical Ecology.