List of Misconceptions of Earthworms

Many of the commonly believed ideas about earthworms are not true.

The nature of earthworms is surrounded with many misconceptions, simply because many people do not know the history and nature of earthworms. Quite frequently, the impact of earthworms goes unnoticed because they seem so small and unimportant. However, earthworms have a profound effect on forests and soil, so understanding the truth about earthworms is actually important in maintaining the environment.

All Earthworms Are the Same

One misconception holds that all earthworms are the same. In actuality, there are many species of earthworms. Each has different physiologic and behavioral characteristics. Different kinds of earthworms can even co-exist in the same areas because of their different inhabiting and feeding habits. The reason that there are different types of earthworms is that they have evolved to meet their adaptive needs. Earthworms originally came to the United States from Europe on boat which used large amounts of soil to keep stable. When the soil was unloaded off the boats upon arriving in the United States, the earthworms were unloaded as well. Because of very different conditions, depending on the region, earthworms have adapted to their physical surroundings over time. The result of this has been the differentiation of many different species of earthworms.

Earthworms Are Beneficial to Soil

A common misconception is that earthworms are beneficial. They do improve soil by decomposing plant litter, changing the porosity of the soil and making it easier for water to flow through the soil. However, earthworms have more negative than positive effects on soil. When they move through soil, they bury matter that lies on the surface of the soil and protects from erosion. They facilitate the increase and growth of weeds because they spread the seeds by moving through the soil. Because of leaching and denitrification, which is the process of creating energy without oxygen, earthworms also cause soil to lose nitrogen and become imbalanced. Overall, earthworms can entirely ruin the forest floor, which has profound effects on the stability of the ecosystem of the forest.

All Earthworms Eat the Same Thing

All earthworms do not eat the same thing. In fact, there can be many species of earthworms living in the same area, because they have different feeding habits. Some earthworms may eat plant litter, while others eat mineral soil or decaying animal matter. The eating habits of earthworms depend on their physiologic adaptations. Many people believe that earthworms actually eat dirt, but this is not true. The food that provides nutrients and energy for earthworms is actually the decaying plant and animal matter. Although they take in some soil when they eat, the soil does not provide any nutrients for them.

All Earthworms Are Found in Northern Hardwood Forests

One misconception holds that all earthworms are found in northern hardwood forests. In reality, earthworms inhabit many different areas. Native earthworms, for example, are not usually found in northern hardfood forests. Rather, exotic earthworms take over in these regions because of permafrost and glaciation, which rid Canada and the northern parts of the United States of the population of native earthworms.

References

• Overcoming Economic Misconceptions: Earthworms
• Renssalaer Polytechnic Institute: Denitrification
• University of Wisconsin at Milwaukee: Earthworms
• Cary Institute of Ecosystem Studies: Invasion of North Temperate Forest Soils by Exotic Earthworms
• Learner: Earthworms Frequently Asked Questions