Human populations continue to have a profound impact on native ecosystems and this research program will continue to
address these impacts. This program will examine how direct and indirect human activities affect forest ecosystems, and test
potential techniques to aid in their restoration. I will focus on how anthropogenic changes at the landscape scale have affected
the diversity and sustainability of hardwood forests. In addition, I will test techniques to restore native tree species and control
non-native shrub species.
In forests and other biomes, invasive species have eliminated or excluded native species, altered soil conditions, homogenized
species composition, reduced biological diversity, and suppressed forest regeneration. Invasive insects and disease can
function as a disturbance agent by eliminating important trees species from across a region in a matter of decades. These
losses reduce biodiversity, alter trophic relationships, and degrade wildlife habitat. In addition, the loss of overstory trees
changes the microenvironment of forest understories, leading to shifts in species composition and community structure.
Invasive plants often displace native species, and the loss of these species have likely caused cascading effects on wildlife
populations, nutrient cycling, and embedded aquatic systems. Further, invasive plants alter the productivity and sustainability of
forest ecosystems, which directly impacts the economic viability of forest land. Economic effects are particularly problematic in
the Midwest, where forests constitute a relatively small component of total land cover but produce high value premier hardwood
veneer and lumber. Therefore, control of non-native plants within is critical to both the ecological and economic integrity of
forests.
Alterations to native disturbance regimes have also led to ecological change and degradation. For example, fire suppression
across much of eastern North America has led to the loss of fire- dependent forest types and the homogenization of species
composition. In particular, fire suppression has led to a well-documented and wide scale reduction in oak species importance
across much of the eastern United States. This genus is economically important and critical to the trophic structure of forests
because of the production of hard mast. Consequently, members of this genus are viewed as foundation species in the eastern
forest. To reverse these undesired changes, land management agencies have sought to restore native fire regimes. However, a
serious lack of knowledge about how fire functions in these forests has stymied managers and highlights the need for additional
research. As oak forests in the eastern United States age and individual oak trees edge closer to natural mortality, this avenue
of research becomes increasing critical to preserving these ecologically and economically valuable forests.
Similarly, chronic browsing by overabundant deer populations has led to the loss of sensitive species, the homogenization of
understory communities, and the failure of forest regeneration. The contemporary landscape of the eastern United States has
created conditions that favor the continued overabundance of deer. However, deer population abundance, and the effects of
these populations, vary with landscape context. Understanding these relationships is critical to the successful management of
deer populations at a state-wide scale.
