The effects of extreme rainfall events on saprotrophic fungal activity in Michigan forests

Abstract

In northern Michigan, a large part of climate change’s impact will be the continual increase in the severity of rainfall events. As it stands, much of the rainfall accumulated in Michigan occurs in the 10 days of highest precipitation. This has implications on the terrestrial environment, and transitively the rate of decomposition of carbon. In forests, saprotrophic fungi mediate a portion of decomposition through the use of extracellular enzymes, such as phenol oxidase. Using phenol oxidase activity as a proxy for fungal activity, we tested the effects an extreme rainfall event (1in/hr) on three different Michigan landscapes with very different soil chemistry and composition. We determined that this large increase in water had an inverse relationship with enzyme activity in both the dune site and the moraine. However, in the wetland, the rainfall simulation did not have much of an effect on the soil moisture and thus did not impact the phenol oxidase activity significantly. Water did not appear to be a limiting factor in any of the sites.