Pattern and Process in Competition
R I C H A R D S . M I L L E R
Department of Biology. University of Saskatchewan. Smkatoon. Canada
I . Introduction .........................................................
1
I1 . The Nature of Competition ............................................
6
A . The Process of Competition .........................................
7
B . Component Elements of Competition ................................
8
I11 . The Ecological Niche .................................................
16
A . Historical Development of the Niche Concept .........................
16
B . Niche Relationships ...............................................
17
I V . Competition in Nature ................................................
20
A . Distribution Patterns ..............................................
21
B . Community Composition ...........................................
26
D . Character Displacement ............................................
30
E . Invasions ........................................................
31
V . Conditions of Coexistence ..............................................
33
48
A . Mammals ......................................................... 49
B . Birds ............................................................ 55
C . Amphibia ........................................................ 67
D . Clustacea ........................................................
68
E . Insects ...........................................................
60
65
References ...............................................................
69
C . Species-Abundance ................................................ 28
V I . Conditions of Competitive Exclusion ....................................
V I I . Species Diversity .....................................................
I . INTRODUCTION
The development of competition theory has traditionally included
three stages: (1) inferences drawn from observation of natural populations. (2) construction of mathematical models and (3) laboratory
experiments designed to test elements of competitive interactions in
controlled environments . Unfortunately. even though competition has
occupied the minds of scientists in various biological disciplines for
many years and is presumed to be a dominant force in biological
evolution. remarkably few testable hypotheses have emerged and almost
all of our conclusions about the importance of competition in natural
systems are still based on speculation and inference .
Darwin (1859) assigned a major role to competition between closely
related species in the process of natural selection . He wrote. “As the
1