Regeneration Failure in Overcup Oak in a Seasonally Flooded Karst Depression
Sinking Pond, a 35-hectare, seasonally flooded karst depression located on Arnold Air Force Base near Manchester, Tennessee has been recognized as a National Natural Landmark for its unique biodiversity. This forested wetland is dominated by a disjunct population of overcup oak (Quercus lyrata) that our research has shown to be exhibiting spatially restricted patterns of regeneration. Since 1970, recruitment of seedlings to small adult size classes has been entirely limited to shallow (less than 0.5 meters) ponding depths. Hydrologic models characterize ponding durations after 1970 as being considerably longer than historical norms, pointing to climate change as the likely factor driving the suppression of tree regeneration in the Pond.
In our current grant from the US Geological Survey, we are following up on our work from 2001 and addressing the following questions:
1) Has tree regeneration in Sinking Pond over the last 15 years continued to be restricted to shallow (less than 0.5 meters) ponding depths?
2) Have ponding durations over the last 15 years continued to be longer than historical norms?
Wolfe, W., J.P. Evans, * S. McCarthy, W.S. Gain, and B. Bryan. 2004. Tree-regeneration and mortality patterns and hydrologic change in a forested karst wetland – Sinking Pond, Arnold Air Force Base, TN. U.S. Geological Survey Water-Resources Investigations Report 03-4217. (Agency peer-reviewed)
* McCarthy, S. and J.P. Evans. 2000. Population dynamics of overcup oak (Quercus lyrata) in a seasonally flooded karst depression. Journal of the Torrey Botanical Society 127:9-18.
Bill Wolfe, USGS
Sarah McCarthy, Alma College
Callie Oldfield, University of Georgia