Geoscience Reference
In-Depth Information
F*
D*
Size-class-based
food web
Taxonomic-based
food web
Figure 3
Illustrating how food webs for both groupings (the more traditional
taxonomic approach, D* and size-class-based approach, F*) were constructed from
the individual-level data (aggregation A in
Figure 1
). Grey links denote the observed
individual feeding interactions, while black links indicate interactions between the
designated nodes of the network (species or size classes, denoted by dashed boxes).
The masses assigned to each node were from aggregations D and F in
Figure 1
(see
Section
II.B.3
for details).
possible level of aggregation for which the comparison could be made was
used, thus enabling the use of the most information available.
What follows are descriptions of each of the nine response variables, along
with which aggregations were used for the allometric relationships examined
and if it was possible to use the response variable in the resolution compari-
son, the grouping comparison, or both. These descriptions are summarized in
Table 2
. A schematic diagram of the possible comparisons between aggrega-
tions is shown in
Figure 2
.
The response variables can be split into three sets (Sections
II.C.1 and II.
C.2
below). The first set of responses examined the relationship between the
trophic ordering of predators and their size. The second explored the rela-
tionships between variation in the diets of predators with their size: that is,
predators are the focal entities. The third set looked at the variation of
species' predators with their size: that is, prey are the focal entities. The
responses measuring diet variation and consumer variation of species were
calculated in the same manner, except that the focal and non-focal species
were reversed.
