Primary tabs

University of Michigan Biological Station

The University of Michigan Biological Station (UMBS) was founded in 1909.

Social

The effects of macro- and micronutrient availability on the soil invertebrate communities and activity

Project Abstract: 
The brown food web encompasses an important group of soil taxa including microbes, microbivores and detritivores, and their predators. In particular, the invertebrate community of the brown food web is responsible for many forest floor processes such as nutrient cycling, including carbon mineralization (decomposition). While it is known that these organisms are affected by key macronutrients (nitrogen and phosphorus), little is known about the effects of other nutrients (trace elements) on this soil community and their activity. Furthermore, less is known about the availability of these micronutrients as forests age. We worked towards filling in this gap by fertilizing the forest floor with sodium, calcium, and manganese and placing decomposition bags in forests at different transitional stages following experimental burns. We predict increased invertebrate abundance, diversity, and decomposition activity in micronutrient-subsidized plots. These increases are expected to be less pronounced in forest stands where these micronutrients were more available. By considering the effects of micronutrients on soil food web processes, this work improves our understanding of controls on ecological processes and their responses to environmental change. Ultimately, this study gives us insight into the complex mechanisms of forest floor processes and how these processes may be changed through disturbance and subsequent recovery.
Investigator(s): 
Paul Moore
Years Active: 
2015
Methods: 
I plan on conducting my all of research in the UMBS burn plots and within the immediate forest surrounding the plots that consists of the oldest plots. First, I will take samples of the soil and leaf litter nutrients from the center of each plot. These samples will include: soil pH, organic matter, available phosphorus, exchangeageable potassium, calcium, magnesium, and amount of N, B, S, Cu, I, Mn, and Zn. I will then have unmodified half-meter quadrats that will contain a pitfall trap and a decomposition bag. I will measure the leaf litter depth in each of the quadrats and set the pitfall traps out for 24 hours twice while running the experiment throughout the summer. At the end of the experiment I will identify the organisms found in the pitfall traps and that have colonized the decomposition bags. I will measure the rate of decomposition using the decomposition bags. I will then be able to analyze any correlations between taxa and the parameters I plan on measuring above. Additionally, I will fertilize half-meter quadrats with Ca, Na, and Mn throughout the summer to maintain the nutrient load. Like the control quadrats described above, the experimental quadrats will have a pitfall trap and a decomposition bag fertilized with the corresponding fertilizer. The pitfall trap will be opened twice throughout the summer, the decomposition bag will be collected at the end of the experiment, and the leaf litter depth will be measured. The organisms in the pitfall and decomposition bags will be identified and patterns/correlations between treatment, leaf litter depth, and invertebrate community will be highlighted. Decomposition rate within each quadrat will be calculated using the decomposition bags.