A Pictographic Key to Leaf Litter Arthropods from the Missouri Ozark Forest Ecosystem Project (MOFEP)


SARAH HEYMAN - Department of Biological Sciences,University of Missouri, (sheyman@biosci.mbp.missouri.edu)

JAN WEAVER -Department of Biological Sciences, University of Missouri, (weaver@biosci.mbp.missouri.edu)

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Role of Leaf Litter Arthropods

In theory, 90% of the biomass produced by a forest returns to the soil. There, bacteria and fungi break down the leaves and dead wood into nutrients that can be taken up again by plants to make new leaves and wood. Although the bacteria and fungi could do this by themselves, it would take a very long time without the activity of the animals that live in the leaf litter and the first few centimeters of soil. Mites (related to ticks) and springtails (primitive wingless insects), whose combined weight may be less than 2 grams per square meter, may recycle almost 30% of the leaves and wood on the forest floor. Indirectly, their feeding breaks litter into smaller pieces, increasing the surface area where decomposition by bacteria and fungi actually take place. Their feeding also coats the pieces with fungal spores and bacteria. Both of these may double or even triple the rate of decomposition by fungi and bacteria.

The leaf litter animals also play an important role in the forest food web. There is 1 1/2 times as much energy stored in the soil and leaf litter of a forest as there is in the trees. In addition, the leaf litter animals are very efficient at turning the food they eat into biomass. As a result they can support long food chains. For example, a mite will eat dead leaves and fungus, this mite will be eaten by a predatory mite, the predatory mite will be eaten by a spider, the spider will be eaten by a beetle, the beetle will be eaten by a mouse, and the mouse will be eaten by an owl. These long chains are important because they allow important minerals like sodium and calcium to be concentrated and then used by animals higher on the food chain.


MOFEP stands for Missouri Ozark Forest Ecosystem Project. This is a long term (100 years), large scale (over 2000 hectares) experimental study of the effects of clear cutting, selective cutting and no cutting on Ozark forest. This experiment is a cooperative effort of the Missouri Department of Conservation's (MDC) Forestry and Wildlife Research units, with the involvement of MDC Natural History SEction, the U.jS. Forest Service North Central Forest Experiment Station, the University of Missouri and others. (If you want to know more about MOFEP click here)

Our Study

Our study is looking at the community of leaf litter animals before and after the cutting treatments. To sample this community we set up 36 5 meter x 5 meter plots. Twelve plots are in forest that will be 10% clearcut, 12 are in forest that will be 10% selectively cut, and 12 are in forest that are not cut. From each plot we collect 4 samples of leaf litter with an area of 0.02 square meters (the area of a 3 lb coffee can lid). The leaf litter is dried and heated under a light bulb and as the animals move down through the litter to avoid the heat they fall into a collecting container of alcohol. We bring these alcohol containers back to the lab and sort the animals under the microscope. An average sample may have 50 species and over 1000 individuals.

Why a Web Page?

In order to describe this community, we need to be able to tell the different species in the leaf litter apart, and be able to recognize them when we see them again. Early on in the study we sketched every new species we found, giving it a unique number and a special identification code. However, as more people became involved in the project we decided it would be better to take pictures of our animals and store the pictures on a computer - kind of an electronic catalog of species. At about the same time, the world wide web was becoming established, so we decided to put our catalog on the web, so anyone with an interest in these animals could see what we had found. With the support of the Bay Foundation, the University of Missouri, and the Missouri Department of Conservation, we purchased a digital camera, a microscope, and a computer that allowed us to set up this web page.


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