Populations

Abstract

The study of populations is particularly important, as it facilitates the description of many ecological processes in quantitative terms. Furthermore, the individual mammal is a recognizable and easily defined unit. By studying populations it is possible to record changes in densities and to quantify the effects of different factors on its numbers. Obviously, densities can vary enormously—for example, in Serengeti, there is one cheetah (Acinonyx jubatus) to every 8500 ha (Schaller, 1970); this is in sharp contrast to the 1200+ voles (Microtus arvalis) per ha recorded from grassland in Poland (Gromadzki and Trojan, 1971). But it is not the magnitude of densities that is important; it is the reasons for prevailing densities in a locality that require explanation. The study of populations goes a long way to providing this information.