Effects of density-restricted food encounter on some single-level competition models

A family of two-species competition models in which density-restricted rates of food enounter are explicitly incorporated generates the following results:

1. 1. Sigmoidal growth. A new model for sigmoidal single-species growth is produced, but one whose inflection point always falls below half the carrying capacity.

2. 2. Comparison with simpler models. In models having shared and exclusive resources, the one or two stable nodes of simpler models may no longer occur in the first quadrant. Such models can simulate how one species by consuming enough overlapping resource can cause another species, unable to maintain itself on its exclusive resources, to go extinct. In models for interspecific interference competition (resource competition purely intraspecific), one or even two more intersections of the zero-isoclines may occur, or the isoclines may intersect once, but with different relative slopes than in the simpler models.

3. 3. Alternative communities. A new model is produced for alternative communities. Conditions for this situation, phrased in terms of parameters measuring feeding and competitive abilities, are rather narrow.