Soil is a full-time home to millions of small animals, consuming living and dead plant material, reproducing, and acting as both predator and prey species. Though larger vertebrates (e.g. voles, moles, mice) are important in shifting and mixing soil, their efforts are frequently overshadowed by worms and other soil invertebrates that help to decompose plant matter, contribute to nutrient cycling, and help to mix soil. Soil invertebrates are topsoil factories; their castings are rich in all the minerals necessary for plant growth and are in a water soluble form so that they are immediately available for plant use.
Students discover the many small creatures that live underneath their feet everyday by collecting and identifying some of the invertebrates that live in the soil. Students learn to take and analyze soil samples, assemble a Tullgren funnel to separate invertebrates from the soil, and practice species identification skills. Observations should prompt a discussion addressing soil as a habitat to invertebrates, biodiversity, and the importance of soil invertebrates to decomposition and nutrient cycling in forests.