Diversity of earthworms and microarthropods in leaf litter
Earthworms are native to Europe but are an invasive species in North America and Asia. Earthworms are important to soil health because they transport nutrients and minerals via waste products and aerate the soil with their tunnels. Earthworms are a source of food for many heterotrophs and are frequently used in commercial and recreational fishing.
Microarthropods are miniscule invertebrates that live in 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.
I hypothesized that the soil quality would be affected by the number of earthworms and microarthropods, and 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.
There was no correlation between the number of earthworms and microarthropods in the plots. Springtails were most abundant and earthworms were least abundant.
My results showed that the number of earthworms and microarthropods were independent of each other. A study by Loranger et al. (1998) showed that abundance of microarthropods was influenced by soil pH, soil depth, water content, food availability, and soil pore size. Future research can be conducted on different species of earthworms and microarthropods.
Cameron, E., et al. 2013. Effects of an ecosystem engineer on below ground movement of microarthropdos. PLOS ONE E62796.
Gerard, B. 1967. Factors affecting earthworms in pastures. Journal of Animal Ecology 36: 235.
Loranger, G., et al. 1998. Impact of earthworms on the diversity of microarthropods in a vertisol (Martinique). Biology and Fertility of Soils 27:21-26.
National Geographic. 2014. Common earthworms: pictures and facts. http://animals.nationalgeographic.com/animals/invertebrates/earthworm