The fact that the results were so mixed shows that the experiment itself was not so intrusive as to kill some of the plants, the researchers say. All the plants, they insist, were treated very kindly. Otherwise, damage would have extended to more species, and one species certainly would not have done better than the control plants.
The researchers have come up with a whole batch of explanations for what may have killed the plants, which means they really don't know, Cahill says. It may simply be that trampling nearby plants to get to the specimens selected for the study had an effect by letting in more sunlight, or stirring up insects. But why wouldn't that have affected all six species?
"I don't honestly know," Cahill says.
It may be that the most plausible explanation is that handling the plants triggered a biological process that either attracted or repelled insects, he adds.
In an effort to fight off the human touch, the Indianhemp may have released chemicals that attracted the insects. The Sulphur Cinquefoil may have done just the opposite.
The researchers have now turned their attention to finding out just what caused the plants to die, and they have broadened the scope to include many other species. The results, which Cahill is now writing up for publication, suggest that many plants may be affected by the human touch. Even handling house plants, he says, may have an effect, either good or bad.
"But we don't know which yet," he adds.
Study Leads to Change
The issue is of considerable importance to scientists because it suggests they may sometimes unknowingly alter the environment they are attempting to study and thus skewer their results, the researchers say.
They liken it to the Heisenberg Uncertainty Principle, a law of physics postulated in 1927 by Werner Heisenberg. The study of subatomic particles, according to Heisenberg, is limited by the fact that just measuring the particles changes their properties. To study them is to change them. Maybe just measuring some plants is all it takes to kill them.
At the very least, the experiment proves one thing, Cahill says. The world is even more complicated than we had thought.
Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.