American Chestnut Past and Future: Implications of Restoration for Resource Pulses and Consumer Populations of Eastern U.S. Forests

Abstract

Forests dominated by oak, beech, hornbeam, and boreal conifers are characterized by resource pulses. Contemporary eastern U.S. oak forests may exhibit dramatic resource pulses in part because of the loss of American chestnut, which comprised 25–50% of the canopy throughout its range. Chestnut loss may have reduced mast resources for wildlife. A newly developed, blight‐resistant hybrid makes reintroduction feasible within several years. We use historical data to model the effects of American chestnut mast on consumer populations, illuminating the potential ecological effects of a successful restoration. We parameterized a stochastic population growth model with mast production data to compare consumer population dynamics both pre‐ and post‐blight. We explored the effect of maximum intrinsic population growth rate, degree of density dependence, and reliance upon mast on consumer response to chestnut loss. We parameterized the models for white‐footed mouse, eastern chipmunk, gray squirrel, and white‐tailed deer. At a northern site 14 years post‐blight, simulated annual mast production decreased 80% and the coefficient of variation (CV) increased 60%. At a southern site 35 years post‐blight, annual mast production decreased by 35% and the CV increased by 76%. Smaller, more variable mast crops translated to reduced abundance and increased variability in simulated consumer populations. White‐footed mice were the most responsive, exhibiting a 48% decrease in population size and 57% increase in interannual variation post‐blight. The reintroduction of blight‐resistant chestnut may fundamentally alter predator–prey interactions, gypsy moth outbreaks, and Lyme disease hot spots through its effect on the character of resource pulses that drive consumer dynamics.