Brown (1995) defines macroecology, a term first introduced by Brown and Maurer (1989), as “a nonexperimental, statistical investigation of the relationships between the dynamics and interactions of species populations that have typically been studied on small scales by ecologists and the processes of speciation, extinction, and expansion and contraction of ranges that have been investigated on much larger scales by biogeographers, paleontologists, and macroevolutionists. It is an effort to introduce simultaneously a geographic and historical perspective in order to understand more completely the local abundance, distribution, and diversity of species, and to apply an ecological perspective in order to gain insights into the history and composition of regional and continental biotas.” (see also Brown 1999, and Gaston and Blackburn 1999).

Lawton (1999), in a review article entitled “Are there general laws in ecology?” emphasizes the important role of contingencies. There are many widespread, repeatable patterns in nature, but few laws that are generally applicable, because tendencies or rules are contingent on the organisms under study. Such contingencies are observable at all levels, those of populations and ecosystems, but are most complicated at intermediate scales, that is, at the level of communities. In the latter, only “weak, fuzzy generalisations” are possible. Therefore, future research that attempts to dicover general laws, should focus on macroecology, which he defines as the “search for major, statistical patterns in the types, distributions, abundances, and richness of species, from local to global scales, and the development and testing of underlying theoretical explanations for these patterns”.