Biology Reference
In-Depth Information
9
.
Some detailed biogeographical/
macroecological patterns
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 popula-
tions 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 biogeo-
graphers, 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 con-
tinental 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 inter-
mediate 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''.
In the following, I discuss some biogeographical/macroecological
patterns in some detail in order to demonstrate contingencies for some
groups, but also general patterns applicable to several groups.
