PARENT SESSION
Oral Session #49: Restoration Ecology. Presiding: J. Callaway.
Wednesday, August 8, 2001. 1:00 PM to 4:30 PM. Madison Ballroom D.
The effects of a light gradient on seedling establishment in an oak savanna restoration.
Hausman, Constance1, Michaels, Helen1, 1
ABSTRACT- Oak savannas are characterized by having open-grown oak canopies with a diverse mix of understory plants. However, controversy has surrounded whether or not oak savannas can be considered a distinctive habitat or are merely transition zones between prairies and forests. The view of savannas as "prairies with trees" de-emphasizes their uniqueness, making them less of a conservation priority. Thus it is important to identify characteristics favoring structure, composition and regeneration of oak savannas. This experimental restoration simulates a variety of cover types that an herbaceous seedling encounters during germination. Seed mixtures of 14 savanna species were sown into 1m2 plots in a randomized block design (with 4 light levels) in early May 2000. Patterns of emergence, survivorship, growth and reproduction for all species were analyzed to determine how light effects an individual species and the patterns of diversity. The maximum proportion of germination was significantly greater at intermediate light levels applied using 30% and 50% shade covers. The rate of germination decreased with increased shade intensity with the slowest germination occurring at the highest percent shade cover. Larger plants were also found in the intermediate light levels at the termination of the experiment. As expected there were also species-specific responses to the different light levels.
KEY WORDS: Restoration, Plants, Savanna, Light