Equitability and Resource Limitation

Abstract

It is suggested that the equitability concept of Lloyd and Ghelardi provides an approach to resolving the question of resource limitation in a specific field situation. The high equitabilities of predaceous insect groups in an annual grassland community indicated that these populations were food limited, whereas the low equitabilities of the herbaceous insects indicated that they were limited by some other factor not directly involved in competition. The increase in equitability of the spiders (all species of which are predatory) during the growing season was tentatively explained on the basis that reaching a resource—limited equilibrium in relative abundances required more time because of the relative immobility of species in this component. These data also demonstrated how the relative abundances of species can undergo a history of adjustment during seasonal succession.