The Lemmings Did It!

By: Daniel Nardini

Let us take the lemming—a small rodent that lives near and in the Arctic circle. Related to the mouse, rat and mole, the lemming is an important part of an eco-system that has existed for millions of years. It is hard to imagine that such a cute little critter like the lemming is causing a raucus in the scientific community. For a number of years, scientists have come to believe that the changes in the types of plants being found in the Arctic circle may be due to global warming. However, a study by the University of Texas may point to something less frightening than many people think. The study, conducted over a 50 year period, has discovered that the change in plants being found in the Arctic may be more related to the habits of the lemming.

Since the Arctic does not get enough sunlight and because of the extreme cold, plants like lichens and bryophytes (related to mosses, liverworts and hornworts) are the most common form of plant life up there. They feed on the vegetation and minerals from the earth. Within the last 20 years, scientists have noticed that the lichens and bryophytes have been disappearing in favor of grasses and shrubs (which need more nutrients and animal life to sustain them). At first, researchers from the University of Texas believed that this was due to global warming. Well, they did a careful experiment. Certain areas made up of lichens and bryophytes were completely fenced off (not sure how that was done) so that the lemmings could not get to them. Next, they let the lemmings run wild in certain other areas.

Those areas that were fenced off remained basically the same. Those areas where the lemmings were allowed to run wild started to change. As the lemming population grew, grasses and shrubs began to replace the lichens and bryophytes. It should be emphasized that grasses and shrubs are the lemmings’ favorite source of food. Hence, these food sources exist for the lemmings, and the lemmings help the grasses and shrubs take root and grow. In other words, mother nature is allowing the lemmings to change the ecology of the areas they inhabit. And how fast or slow, and how many or how few lemmings there are determines the rate of increase of grasses and shrubs in the areas in the Arctic circle.

This specific phenomenon is not new—it has been going on for unaccounted millions of years where animal populations have a direct or indirect impact on the environment. Of course, the change in climate might influence the growth or decline in the population of any given species, but this is not always the case. Why the lemming population has gotten larger may simply be no more than more favorable population growth based on abundant food sources that they helped to create. This in of itself does not suggest climate change—simply that the circumstances are right for lemmings to grow. In another ten years it could reverse and the lemming population could decline and even almost disappear. Mother nature is funny that way, and even after a century of study there is much we do not understand about our natural world.

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