Noel B. Pavlovic and Ralph Grundel

Research Ecologists, U.S. Geological Survey


Biodiversity Changes Across a Midwest Prairie-Oak Savanna-Forest Gradient


Woody vegetation manipulation is a common approach and goal during oak savanna restoration management along the grassland to forest continuum. We investigated the tradeoffs in plant and animal community composition related to changes in woody vegetation density along this continuum in northwest Indiana and predicted what landscape compositions, related to woody vegetation cover, might maximize diversity of plant and animal communities. We sampled vegetation, birds, reptiles, amphibians, butterflies, and bees across the prairie-savanna-forest gradient among 25 sites at Indiana Dunes National Park, and Tefft and Hoosier Prairie Nature Preserves. Thus, five prairie, oak scrub, oak savanna, oak woodland, and oak forests were sampled. We found that different taxonomic groups responded to different environmental factors (e.g., fire regime, canopy cover, ground cover, plant diversity, composition of plant in flower, etc.) across the gradient. In addition, with birds, we showed that we could not maximize species diversity and conservation value of species simultaneously. From this research, we discuss the benefits and drawbacks for oak savanna restoration for the taxonomic groups and what kinds of landscapes would maximize which goals.


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