Biology Reference
In-Depth Information
1 (= carrying
capacity for
species)
5
bats
4
birds
filling of
niche space
and SES
values
mamm
a
ls
3
ants
2
herps
1
invertebrates
fish parasites
0
0
fish
vagility
size of
individual or
population
Figure 11.1. Diagram representing filling of extant niche space as indicated by SES
various vertebrate and invertebrate groups. Note that taxa comprising large (relative
to their habitat) species and/or species with great vagility (bats, birds, mammals, ants)
have greater SES values than taxa containing small species and/or species with little
vagility. Data from Gotelli and Rohde (
2002
) and Gotelli and McCabe (
2002
).
only one of many mechanisms. Others include the affinities of species for
non-overlapping habitats leading to segregation, events that reflect bio-
geographic and evolutionary history, etc. (references in Gotelli and
McCabe
2002
).
In interpreting Figure
11.1
, two important points must be kept in mind:
(1) vagility and/or dispersal may be more important than body size, because
populations of animals at the top of the food chain often have smaller
biomass than smaller herbivores ''below'' them; (2) the body size of species
has to be measured relative to their habitat. Thus, fish, which have the
lowest standardized effect sizes (SES) values of all communities tested, are
