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Microarthropods, earthworms, and leaf litter

Iesha Brooks
Ecology class, BIO 342, Biology Department, DePauw University
Fall semester 2015

Microarthropods are small invertebrates that live in the soil and leaf litter.  Microarthropods are important in controlling the rate of leaf litter decomposition and nutrient cycling.  Microarthropods include mites, spiders, springtails, pseudoscorpions, and insect larvae.  Earthworms are also important to soil health because they transport nutrients and minerals via waste products and aerate the soil with their tunnels.  The goal of my study was to test the relationship between the abundance of earthworms and microarthropods in soil and leaf litter samples in the DePauw Nature Park.

I hypothesized that there would be a correlation between the abundance of earthworms and microarthropods.

I sampled microarthropods and earthworms in seven 35 x 35 cm plots along the Rail Trail in the Nature Park.  I collected leaf litter in plastic bags, dried the leaf litter using Berlese funnels, preserved the organisms in 70 percent ethanol, and counted the number of microarthropods in the samples.  I used the hot mustard extraction technique to measure the abundance of earthworms.  I prepared 7 gallons of mustard powder solution, cleared off leaf litter to expose the top layer of soil, poured the mustard solution on to the soil, collected earthworms that emerged, and measured the wet weight of earthworms.

Results and Discussion
There was no correlation between the number of earthworms and microarthropods in the plots.  Springtails and mites were the most abundant microarthropod and earthworms were least abundant.  Future research can be conducted on different species of earthworms and microarthropods.