Problem: 
For a stable network with robustness, which way has more effects on it: change one route heavily, or change several place slightly?

Formulated question:
Supposing there is a food web, if I want to decrease an animal (for example mouse's) food quantity by 50%, which is more efficient to reach this goal: change one chain in food web by 90%, or  change several route by 30%?

Answer: 
Food webs and other evolved biological networks almost always tolerate a 90% change of a RANDOMLY picked link, however the same networks disintegrate if a link with high betweenness centrality is INSIGHTFULLY SELECTED. So if you  compare to a strong but RANDOM link change then I could imagine that SEVERAL small changes have a higher chance to hit a link of high betweenness centrality for which even a small change has more impact on  the whole network than the single, random, large change. For ODE  dynamics on networks there is a powerful concept of Metabolic Control Analysis (MCA) to access the impact of link changes.