He suggests that there are four things we need to remember about species interactions in order to design appropriate conservation programs. Different interactions happen in different populations.
Interactions can evolve rapidly.
I've already mentioned the change in beak morphology of the Hawaiian i'iwi, but it is only one example. Recall that populations occupying clear-cut meadows, which were created in the late 1960's, switched their food plant preferences from Pedicularis semibarbata and Castilleja disticha to Collinsia torreyi . There is no particular direction in which interactions will evolve. Because the genetic basis of interactions may differ from one population to the next and because the ecological details of the interaction are also likely to differ from one population to the next natural selection is likely to produce different results in populations that evolve independently of one another. Habitat fragmentation may contribute to evolutionary divergence among populations that were once similarly adapted.