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The Acorn Connections

Clive G. Jones
Institute of Ecosystem Studies

Gypsy moth defoliation and Lyme disease are major problems in eastern United States oak forests. Using a combination of long-term studies and large-scale experiments, Dr. Richard Ostfeld, Dr. Jones and other colleagues have shown that acorns initiate a complex series of ecological chain reactions. These interactions can ultimately determine whether or not gypsy moth outbreaks will occur, and may determine Lyme disease risk to people. Acorns are a key food for white-footed mice. The mice are key predators on gypsy moth pupae. When there are many acorns the mouse population increases, which keeps the moth population low. However if there are no acorns, the mouse population collapses allowing the moth population to increase. Acorns also attract white-tailed deer into oak forests to feed on acorns. The deer carry adult ticks that drop off and spend the winter in the oak forests. The next year the female ticks lay eggs that hatch into larval ticks. The larval ticks are not infected with the bacteria that cause Lyme disease, but become infected when they feed on the mice that have increased because of acorns. This means that the risk of Lyme disease may be higher in oak forests two years after a large acorn crop. Acorns initiate many other chain reactions, and gypsy moth defoliation has many effects on the forest, including a reduction in acorn production. The research has important implications for understanding forest ecosystem health and human health, and is part of a larger collaborative research program called FORSTAD (Forest Responses to Stress and Damage) that is trying to understand how the complexity of interactions among species affects the functioning of forest ecosystems.

Collaborators
Dr. Charles Canham, IES
Dr. Felicia Keesing, IES Visiting Scientist, Sienna College
Dr. Gary Lovett, IES
Dr. Richard Ostfeld, IES
Mr. Eric Schauber, Graduate Student, IES & University of Connecticut, Storrs
Dr. Peter Turchin, University of Connecticut, Storrs
Dr. Jerry Wolff, University of Memphis, Tennessee

Selected Publications

An Overview of the Acorn Connections

Scientific Correspondence on the Acorn Connections