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Northern Research Station
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You are here: NRS Home / Research Programs /Forest Disturbance Processes /Climate Change and Events / Nitrogen deposition effects on symbiotic fungi in northern hardwood forests
Forest Disturbance Processes

Nitrogen deposition effects on symbiotic fungi in northern hardwood forests

[photo:] This research examines whether nitrogen deposition effects on mycorrhizal fungi might be contributing to sugar maple decline. Research Issue

Atmospheric nitrogen deposition from fuel combustion and agriculture is falling from the air onto natural ecosystems, leading to changes in nutrient availability and acidification of soils and waters. Symbiotic fungi, called mycorrhizal fungi, are essential to tree nutrient uptake, and in some ecosystem types have been found to decline in abundances and diversity in response to nitrogen deposition, with possible negative effects on plant uptake of soil resources. We wanted to understand the impact of nitrogen deposition on the mycorrhizal fungi associated with sugar maple dominated northern hardwood forests in Michigan. Sugar maple decline has become a serious problem in our region. Understanding whether nitrogen deposition effects on mycorrhizal fungi might be contributing to this decline is critical to our ability to protect these forests.

Our Research

The Michigan gradient consists of four northern hardwood sites over a natural deposition and climate gradient in Michigan. These sites have also had replicated plots with experimental additions of nitrogen since 1994. At these sites we are examining the effects of N inputs on the abundance, community composition and structure, and function of the mycorrhizal fungi associated with sugar maple.

Expected Outcomes

We have demonstrated that the abundance of mycorrhizal fungi declines in response to nitrogen deposition. The community structure of the fungi also appears to be changing. This information, plus data on community function, can be used to inform management and policy decisions on how to respond to nitrogen deposition and how to manage forest fertilization.

Research Results

Van Diepen, L.T.A., E.A. Lilleskov, K.S. Pregitzer, R.M. Miller. 2007. Decline of arbuscular mycorrhizal fungi in northern hardwood forests exposed to chronic nitrogen additions. New Phytologist 176: 175-183.

Research Participants

Principal Investigator

  • Erik Lilleskov, US Forest Service- Northern Research Station Research Ecologist

Research Partners

  • Linda van Diepen, Michigan Technological University
  • Kurt Pregitzer, University of Nevada, Reno
  • Andrew Burton, Michigan Technological University
  • Donald Zak, University of Michigan
  • R. Michael Miller, Argonne National Lab

Last Modified: 07/24/2009