Flowering plant and pollinator responses to oak savanna restoration

Temperate savannas are among the earth’s least conserved ecosystems.  They were once a prominent feature in the landscape of the Midwestern United States, where now they are one of the rarest communities in the region due to direct conversion for European settlement and agriculture along with a disruption of the historical fire regime.  High quality natural communities often help guide restoration efforts of more degraded sites, and the near absence of high quality oak savannas in Michigan creates uncertainty regarding the best methods for savanna restoration there.  In 2010 we initiated a long-term restoration study on a closed-canopy fire-suppressed oak savanna remnant at MSU MacCready Reserve in Jackson County, MI.  Specifically we are comparing approaches of gradual cutting of non-oak, fire-intolerant woody species coupled with fire (cut+burn), fire alone (burn), and unmanaged reference plots.  In doing so, we hope to better understand how restoration approaches affect pollinator communities and their floral interactions.  Here we present data on initial responses of ground-level light availability, abundance and species richness of forbs in flower, and native bee abundance.  The plant community is responding to increased light availability in cut+burn plots, with formerly light-suppressed species blooming for the first time.  In the future we hope to explore pollinator community structures between treatments, and determine which environmental factors affected by our restorations (e.g. light) best explain pollinator diversity and community structure.  These results help us begin to better understand how restoration approaches affect pollinators that could alter plant community trajectories and overall restoration success.