By Bob Ferris
As a scientist I spend a lot of time thinking about science, particularly ecology. And while I was on this Two Talking Wolves Tour with Todd Wilkinson I did a lot of driving which is also a good opportunity for contemplation. In fact, as I drove south after the last presentation at Third Place Books in the Seattle area I had about two and a half hours to think while I was driving through torrential, have-to-pullover-now-style downpours in the wee hours of the night.
The above experience could largely explain why I started to think of ecology as a river, but the analogy works even when you are not worried about hydroplaning to your death between two semis who have made your world a little like the inside of an out-of-control carwash. Replace habitat for gravity in this context and you have a system that generally flows downhill—swiftly or slowly—depending upon the “slope” or habitat quality. With no slope you have no current resulting in a stagnant pool and that is fairly similar to what we see when habitats are seriously degraded.
The fun and mischief in both ecology and rivers come from the anomalies. Rocks, tree trunks, differentially erodible substrates all make rivers do funny things like causing eddies, rapids and slack water. These anomalies have a similar impact on rivers flowing to the sea as do changes in weather patterns, invasive species presence, unsettled predator-prey dynamics and human disturbances like clearcutting and livestock grazing have on ecological functions. But just as it would be ridiculous to conclude that all rivers run uphill because of eddies, it makes little sense to conclude that wolves are wiping out elk because populations levels of this ungulate are declining from historically high and unsustainable numbers in Yellowstone.
Rivers and ecology are complicated and take time to understand or even to approach understanding. Perhaps that is why many of us run them, study them or do both. But it is also why these variable and complex systems should not be approached casually and without forethought or preparation (My friend Martin and I at left scouting a Class IV rapid on the Lower Salmon River in Idaho). Anyone who has done a 180 in a canoe over seemingly calm waters or has had to change their thinking as more studies emerge on a particular phenomenon, understands that there is peril in thinking that a single observation or finding allows you to draw broad conclusions. Those who parrot the claim that wolves are wiping out elk should understand that to many of us who study these systems and their assemblages of dynamics that is just like saying all rivers run uphill.