Niche width: biogeographic patterns among anolis lizard populations

TLDR: One aspect of the niche width of a population refers to the variety of resources used by the entire population, which may be measured by the variance of the population's resource-utilization function.

Abstract: One aspect of the niche width of a population refers to the variety of resources used by the entire population. This aspect may be measured by the variance of the population's resource-utilization function. Two components make up a population's niche width. The within-phenotype component measures the spread of resources used by the average individual in the population. The between-phenotype component measures the variety of individual specializations in the population. The sum of these two components yields the total niche width. Calculation of these measures is illustrated with data from Anolis lizards. If the population's niche width is mostly composed of the within-phenotype component, it is virtually a monomorphic population of generalists, whereas if mostly the between-phenotype component, it is virtually a population polymorphic with pure specialists. Anolis populations tend more to be monomorphic with generalists than polymorphic with specialists. Recent ecological theory entails four predictions s...