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Mac A. Callaham, Jr.

Team Leader/Research Ecologist
Center for Forest Disturbance Science
320 Green Street
Athens, GA 30602-2044
United States
Current Research

I am interested in soil ecosystem responses to natural disturbances (fire, wind, and flood), forest management practices which seek to simulate disturbances (prescribed fire, thinning, harvesting), and anthropogenic disturbances (e.g. invasive species).  I am particularly interested in responses of soil biota (e.g. earthworms, herbivorous insects, soil microbes, etc.) to these disturbances and land management practices, and how changes in invertebrate assemblages may lead to changes in other components of forest systems (e.g. nutrient relationships, plant-herbivore relationships).  In addition to pure soil biology, I am also interested in elemental dynamics, and specifically the effects of prescribed fire on soil organic matter and toxics (soil carbon, nitrogen, and mercury).

  • Kansas State University, Ph.D., Biology, 2000
  • University of Georgia, M.S., Agronomy, 1996
  • University of Georgia, B.A., English, 1994
  • University of Georgia, B.S., Zoology, 1994
Featured Publications
Other Publications
Research Highlights

Earthworms, Millipedes, and Soil Carbon in the Eastern U.S.

Year: 2016
Earthworms, millipedes, and other soil invertebrates directly contribute to forest soil processes such as leaf litter decomposition and soil organic matter formation. There is relatively little known about how the composition of soil macroinvertebrate communities varies across temperature and moistu...

Soil fauna are of vital importance to soil processes and deserve attention

Year: 2017
Although soil fauna are critically important for many ecosystem services, they are often neglected by researchers. Scientists at the Forest Service and the University of Georgia discuss reasons for this in their review of how disturbance affects these organisms.

Invasive earthworms have unexpected effects on other soil organisms

Year: 2017
Invasive earthworms alter the structure and function of soil. Forest Service scientists show that these earthworms decrease the abundance of springtails, but act as a food source for centipedes. These changes are likely to alter the communities of other soil-dwelling organisms, with potential rippli...

Short-circuiting an Invasional Meltdown

Year: 2014
Chinese privet is an invasive plant species in flood plain forests of the southeastern U.S., in some cases occupying up to 80 percent of available riparian floodplain forest habitat. Non-native invasive earthworm species are found in the same soils where Chinese privet is abundant. In this study, Fo...

Prescribed Fire to Stem the Tide of Earthworm Invasion

Year: 2015
Asian earthworms are currently invading eastern deciduous forests from Georgia to Vermont. Because these earthworms eat leaf litter in the forest floor, Forest Service scientists and collaborators hypothesized that applying some heat and removing some of this food source with prescribed fire might s...