TURNOVER PATTERNS AND SPECIES LONGEVITY OF LARGE MAMMALS FROM THE LATE PLIOCENE AND PLEISTOCENE OF SOUTHERN AFRICA - A COMPARISON OF SIMULATED AND EMPIRICAL-DATA

Two models of faunal turnover patterns were tested against observed frequencies of first and last appearances of large mammals from the late Pliocene and Pleistocene of southern Africa. Simulations based on a constant turnover model with subsequent sampling at fossil sites adequately explained the empirical data. Under a model with turnover pulses at the times of putative climatic events, i.e. at 2.5 and 0.9 Myr, simulated ranges of first and last appearance frequencies encompassed the fossil data with the exceptions of four time intervals in which observed frequencies of last appearances did not fit the model. Concordance between simulated and empirical data for apparent species longevity did not differentiate between the two models, but served to confirm the general validity of the assumptions of the simulations. Differential sampling of species at fossil sites is the simplest explanation for the observed ''trends'' in species appearances. The fossil record is then explicable by a model of constant turnover without the unnecessary conjecture of periodic abiotic forcing.