Trophic Relations and Ontogenetic Niche Shifts in Aquatic Ecosystems

Abstract

These ontogenetic niche shifts can be a consequence of changes in an organism's foraging ability, such that it feeds more efficiently on different sizes or types of preym or in different habitatsm as it grows. IN THIS CASE, WE MAY HAVE MORE OF A CONTINUOUS SHIFT / GRADIENT IN RESOURCE USE THAT OCCURS AS A FUNCTION OF SIZE. NOT A DISCRETE ONTOGENETIC SHIFT. Stages showing density-dependent responses to diferent resourecs, provides a likely mechanism whereby the densities o consumers and their resources will positiely covary within a life-stage Two life-stage model for competing species In cases where trophic levels are not clearly defined and many species comprise a trophic level, a thorough understanding of the processes that control resource and consumer abundances must include informaiton aout the way consumers utilize resources (and therefore influence the resources' mortality rates). Foraging theory is a powerful tool... Equilibrium Population densities are a result ofboth top down (predaton) or bottom up (competition) forces.