Geoscience Reference
In-Depth Information
Taxonomic groupings
2
2
2
B
C
D
Taxonomic-based approach
0
0
0
-2
-2
-2
-4
-4
-4
-6
-6
-6
-4
-3 -2 -1 0
1
2
3
-4-3-2-10123
-4-3-2-10123
Comparisons between resolutions
2
A
0
-2
Comparisons between
groupings
-4
-6
-4 -3 -2 -1 0
1
2
3
2
2
E
F
0
0
-2
-2
-4
-4
Size-class-based approach
-6
-6
-4-3-2-10123
-4-3-2-10123
Size-class groupings
Level of increasing
resolution
Figure 2
An illustration of the framework used in the study. Log
10
predator body
mass is on the x-axis and log
10
prey body mass is on the y-axis, the line denotes the
one-to-one relationship where predator mass equals prey mass. We use the letters A-F
to depict aggregations into different levels of resolution and groupings. The raw data
of individual predator-prey interactions (A) were aggregated using a taxonomic-
based approach to generate different levels of resolution (A-D) or binned into body
size classes using a size-class-based approach to provide groups (E and F) which could
be contrasted with the taxonomic aggregations. For each response variable, compar-
isons could then be made, either between the levels of resolution or between the two
approaches to grouping (all possible comparisons are denoted by dashed and dotted
arrows, respectively). The data shown in this example are from Broadstone Stream,
depicting the predator mass to prey mass relationship. In the analyses, only the
comparisons between A and D, and B and E were carried out for this particular
response variable (prey body mass) (see
Table 2
for details of which comparisons were
done for each response). Solid arrows illustrate along which axis the aggregations
were conducted, that is, no aggregation for the individual-level data (A—highest
resolution); aggregation along the x-axis (focal axis) for resolution B and grouping
E; and aggregation along both the x- and y-axes (non-focal axis) for resolution C and
D, and grouping F. For the details of the levels of resolution and grouping, see
Section
II.B
.
