Protozoan species accrual on artificial islands in differing lentic and wetland systems

Abstract

In the recently broadened context of insular biogeographic theory, artificial substrates might well be considered as initially barren islands with the surrounding natural community acting as a source pool of potential colonists. In an attempt to relate protozoan communities forming on polyurethane foam (PF) substrates to their environments, a series of field experiments were performed in several aquatic and semi-aquatic (wetlands) systems in Michigan, Virginia, and Colorado. Results were considered in the context of island colonization theory. Given relatively stable environmental conditions and sufficient time to colonize, protozoa formed highly replicable communities on PF substrates; MacArthur & Wilson's equation for noninteractive island colonization, S = Seq ·(l-e−Gt ), accuratelt described the process of species accrual in most cases. Sites were compared using non-linear regression estimates of the parameter, G, which reflects the rate at which substrates attained equilibrium species numbers. In general, the rate of equilibrium acquisition reflected differences in productivity and structure between the protozoan communities from the various habitats and systems studied.