Carl Wernicke: Nature Takes Care Of Itself

Feb 12, 2015

Credit IHMC

Roger Smith, who lectured recently at IHMC on his work rehabilitating injured birds of prey, made a comment during an interview with me that could not be more true. He said that to fully appreciate what is going on in nature, you have to understand it.

   Over many years of reporting on environmental issues, that came home to me again and again. I first really got it when a local environmentalist got me to understand that you literally can miss the forest for the trees. What looks like a healthy forest can in fact be a dysfunctional ecosystem in decline, distorted by poor management or other impacts caused by people.

   Left to itself, the longleaf/wiregrass ecosystem that used to dominate Northwest Florida and the Southeast is one of the richest biological systems in the world. But decades of interference have left it on its figurative knees, a circumstance hidden by the abundance of pine trees across our landscape.

    I remember the story told to me once by a biologist engaged in restoring longleaf on a 40,000-acre patch of woods here in Northwest Florida. He had ridden with a local resident to a spot far out in the woods, where the young man threw his arms out and said this is why I love this place. The biologist told me that he didn’t have the heart to tell the man that they were standing in the middle of a planted pine plantation, the tree equivalent of a cornfield.

    This works, too, with efforts to return prescribed burning to area forests, which has more impacts than you can count. One of my favorite stories is how regular fire restores calcium to the ground, where it is consumed by ants that make up a big part of the diet of the red-cockaded woodpecker. Without regular fire, the ants the woodpeckers eat are low in calcium, so the shells of the woodpeckers’ eggs also lack sufficient calcium, leading to high breakage and low reproduction rates. Without understanding the role of fire in the ecosystem, we could watch woodpecker populations decline without being able to figure out why.

     Recently I read another cool story in this vein. In Colorado, scientists from the University of Florida figured out that bears are critical to the survival of rabbitbrush, an important plant in mountain meadows. It seems that ants eat another insect that preys on a third insect, called a leafhopper, that damages rabbitbrush by sucking its sap. Too many ants means a decline in the predator, which means an increase in leafhoppers, which means a decline in rabbitbrush, which provides a wide range of benefits to birds, butterflies and small rodents. Less rabbittbrush means a less robust mountain meadow.

    Now, it turns out that bears love to eat ants and their grubs. So when bears are present, there are fewer ants to attack the predator that eats the leafhopper, so there’s more rabbittbrush and, therefore, more birds, butterflies and small rodents, which is good for animals like foxes, hawks and owls.
  

That’s pretty cool.