Ecology has way too many variables, but examples are instructive. Melissa Breyer on Treehugger.com covers more research relevant to my own interest in Lyme Disease, which is already alarming, specifically on how small rodent predators suppress the presence of illness in mice:
After two years of painstaking work – trapping mice, counting ticks, testing the ticks, and dragging a blanket on the ground to capture additional ticks – [Tim R.] Hofmeester had some rather conclusive-seeming data. “In the plots where predator activity was higher, he found only 10 to 20 percent as many newly hatched ticks on the mice. Thus, there would be fewer ticks to pass along pathogens to next generation of mice,” writes [Amy Harmon in The New York Times].
Curiously, areas of higher predator activity didn’t correlate to a decrease in the numbers of mice themselves, just a lower rates of infected ticks. Hofmeester suggests that the predators’ activity curtailed the roaming of the small mammals, which was enough to make an impact.
“This is the first paper to empirically show that predators are good for your health with respect to tick-borne pathogens,” Dr. Taal Levi, an ecologist at Oregon State University, told The Times. “We’ve had the theory but this kind of field work is really hard and takes years.”
Another reason to keep the cats. Although I wish they were a little more active. Insouciant bunnies, now we have insouciant mice. Might as well put lounge chairs out for them.
