Characteristics of coenoclines, or community gradients, were studied as a basis for simulating the distribution of species populations along environmental gradients. A computer program is described which is inexpensive, realistic in the manner in which species are distributed, and flexible in that levels of alpha and beta diversity, sampling error, and other parameters can be varied. The simulated coenoclines are of interest in connection with dominance and diversity relations, measurement of ecological distance, and ordination of community samples.