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based on size classes (with a mean slope of 0.366) than when they are
aggregated into species-based food webs (mean slope of 0.278, t
¼
3.111,
df
¼
6, p
¼
0.021).
2. Size Structure Dimension Set #2: Diet Variation
a. Predator Mass-Variance of Prey Mass (Resolution). There was no sig-
nificant difference between the slopes (estimated by linear regression) of the
highly (B) and less resolved data (D) (t
¼
0.635, df
¼
6, p
¼
0.549,
Figure 8
B).
b. Predator Mass-Variance of Prey Mass (Grouping). When the data were
grouped into size classes (E), the estimates of the slopes from the linear
regressions were not significantly distinguishable from the slopes of taxo-
nomic aggregation (B) (t
¼
0.780, df
¼
6, p
¼
0.466,
Figure 8
C).
c. Predator Mass-Range of Prey Mass (Resolution). There was no signifi-
cant difference between the slopes (estimated by linear regression) of the
highly (B) and less resolved data (D) (t
¼
1.311, df
¼
6, p
¼
0.238,
Figure 8
D).
d. Predator Mass-Range of Prey Mass (Grouping). Upon visual inspec-
tion of the size-class aggregation (E), a clear hump-shaped relationship was
evident in most of the study systems. Therefore, a quadratic term was
included in the linear regressions for both aggregations. Rather than a
comparison of the slopes (the first-order coefficient), the second-order coeffi-
cients were compared. In this instance, the paired t-test was testing the
hypothesis that the size-class grouping produced relationships that were
more humped than the taxonomic grouping (B). Such a pattern was indeed
found (
Figure 9
), the size-class grouping had a mean coefficient of
3.767,
while the taxonomic grouping had a mean coefficient of
1.178 (t
¼
3.094,
¼
¼
df
6, p
0.021,
Figure 8
E).
e. Species Mass-In-Degree (Generalism). Linear regression was used to
estimate the slopes in each study system (
Figure 10
). No significant difference
between the slopes of the taxonomic (D*) and size-class food webs (F*) was
found (t
¼
0.520, df
¼
6, p
¼
0.622,
Figure 10
A).
3. Size Structure Dimension Set #3: Predator Variation
a. Prey Mass-Variance of Predator Mass (Resolution). Slopes of the sys-
tems were estimated using linear regression. The paired t-test found no
significant difference between the high (B) and the low (D) resolution aggre-
gations (t
¼
1.101, df
¼
6, p
¼
0.313,
Figure 11
B).
