The Last Butterflies by Haddad Nick;

Author:Haddad, Nick;
Language: eng
Format: epub
Publisher: Princeton University Press
Published: 2019-04-17T00:00:00+00:00

KILLING BUTTERFLIES TO SAVE BUTTERFLIES

After repeated visits to the artillery ranges, my concept of restoration for the St. Francis’ Satyr turned upside down. Intense and frequent disturbances caused by artillery fire were not, after all, harmful to butterflies. Large St. Francis’ Satyr populations in the ranges pointed to exactly the opposite conclusion. In addition to fire, ranges supported healthy populations of beavers, which flooded large stretches of streams. There was a giant difference between what I observed outside the artillery ranges and what I observed inside. The extensive metapopulations within formed an interconnected network of wetlands, such that individual butterflies from undisturbed wetlands could colonize disturbed areas where the vegetation was recovering. I could see now that disturbance was not harmful to the butterfly populations.

This experience forced me to admit that nearly every measure I had taken to conserve the St. Francis’ Satyr outside the artillery ranges had been wrong. My lab’s conservation actions had protected the butterflies from direct harm, including via natural disturbances. My rationale had been that the St. Francis’ Satyr had existed in these areas for this long, and so, I assumed, it would continue to remain safe.

One of these wrong decisions occurred in my first year of research. A beaver dam grew downstream of a newly discovered St. Francis’ Satyr population. Biologists were worried that this dam would grow so big that it would flood out the population. The next year, the beavers were gone. The road engineers had used our concerns and the dam’s flooding of a road as justification to remove the beavers. In the ensuing years, the butterfly population boomed. It expanded to colonize the area that had been underwater. A decade later, however, with no further disturbance, the population collapsed.

By doing nothing, I was, in fact, killing the butterflies. If protected from disturbance but otherwise let be, their open habitats continued through a natural course of succession, giving way to shrubs and then trees. These woodlands excluded the St. Francis’ Satyr’s host plant, and thus the St. Francis’ Satyr. Trees then introduced environmental feedback, acting like straws that sucked water from the soil. In doing so, they caused wetlands to dry. This reduced the habitat’s potential for the St. Francis’ Satyr even further. The irony was that by preventing fire or floods from killing the butterflies, we were killing them anyway. Herein lies a great paradox exposed vividly in the artillery ranges: we need to kill some butterflies to save butterflies—indeed, to save a species.

Unlike my restoration targets outside the artillery ranges, the environments inside the ranges were turbulent. Fires and floods introduced constant change to the St. Francis’ Satyr’s habitats. The processes that seemingly destroyed habitat at the same time initiated a process that regenerated host plants and habitat the butterfly needed to thrive. What I observed firsthand was how artillery helped to recreate natural disturbances and habitat conditions that once defined this landscape before the army—before people—ever walked on it. It did so in at least two ways.

First, artillery-generated fires replaced natural fires.

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