Figure 1.
The food web of Kelian River at sampling site 1 (the pristine river segment).
The inset on the left provides the full names of trophic groups. Nodes with pink background represent fish groups. There are two symmetrical links (PRED/OMNI and CARN/PRED), otherwise the network would be acyclic. Network drawn by COSBILAB Graph [17].
Table 1.
The structural and dynamical importance indices used in this paper (see definitions and explanations in text).
Figure 2.
The food web of the pristine river (site 1), size of nodes is proportional to six measures of importance: D (a), nBC (b), K (c), TI3 (d), IH(V) (e) and KH(V) (f).
Network drawn by COSBILAB Graph [17].
Table 2.
Importance ranks of trophic groups in the food web of the pristine river (site 1).
Figure 3.
The matrix of simulated dynamical interaction strengths in site 1(from groups in row i to groups in column j).
Four simple interaction types were analyzed: indirect self-loop is yellow, predator-prey interaction is red, prey-predator interaction is purple and trophic cascade is green (a). None of these interactions is in white. In (b), the 20 strongest simulated interactions are shown (apart of the 14 self-loops that are obviously the strongest ones). Direct (red and purple) and indirect (only white, as no green trophic cascade appears in the top 20) interactions are well-mixed. The strongest one is a direct effect from GRAZ to POM, the second strongest effect is indirect (from HERB to OMNI). The shown 20 interactions are followed by 162 weaker effects, their rank is shown in (c). Here, the x axis is the rank of interactions, while the y axis is their strength shown in (a).
Figure 4.
The IH(V) value for four selected trophic groups at each site.
The top-down effects of fish on the dynamical variability of other groups in increasing in the more human-influenced site.
Figure 5.
Abiotic variables (turbidity in (a) and temperature in (b)) followed by biotic ones (IH(M) for OMNI in (a) and TERR in (b)).
To help visual comparability, values have been transformed in such a way that the minimum and the maximum value be equal to 0 and 1, respectively. The x axis is the series of study sites.