portions of shrubby vegetation and canopy species, including the canopy tree Celtis
 laevigata Willd. sugarberryy). The high climbers included Cissus trifoliate L. (possum
 grape), Parthenocissus quinquefolia, and Cynanchum scoparium Nutt. (leafless
 Cynanchum or leafless swallowwort).

 At Turtle Mound, Norman and Hawley (1995) found that winter freezes have
 presumably caused vegetation dieback on shell mounds, which they believed resulted in a
 general increased frequency of vine occurrence for both temperate and tropical species.
 They hypothesized that the reason was that many vines have rhizomes and underground
 tubers that can survive underground and resprout after periods of freeze (Norman and
 Hawley 1995). Other disturbances at Turtle Mound including boardwalk construction
 and continued removal of encroaching vegetation also may have stimulated the growth of
 vines.

 Monk (1965) sampled 60 mixed hardwood forests in north central Florida. He
 found many vines species occurring throughout these sites. Vitis rotundifolia was found
 at 90% of the sites, followed by Gelsemium sempervirens, Parthenocissus quinquefolia,
 Smilax bona-nox, and Toxicodendron radicans being found at 81%, 80%, 79%, and 75%
 of the sites, respectively. Additionally, he found Campsis radicans on 37% of the sites
 and Galactia elliotti on 2% of the sites.


 Ecosystem Succession

 Ecosystem succession encompasses changes in the environment over time. While
 no unified theory of succession has been accepted, many have been hypothesized. Vines
 have been theorized to play an important role in succession, and a history of successional
 theory is provided below to further explain the possible role vines play in succession.

 Cowles (1899) was one of the first to study vegetative succession. He described
 changes in vegetation over time on the dunes of the Indiana portion of Lake Michigan.
 Later, Tansley (1935) described succession based on the concept of ecosystems and
 vegetation in the landscape as a mosaic controlled by environmental factors including soil
 moisture, nutrients, topography, perturbations, and animal activity. Then in 1936,
 Clements defined succession as being a set path that ecosystems follow based solely on
 the prevailing regional climate and the physical conditions of the environment. Soon
 after, Lindeman (1942) described ecological succession as ecosystem based and
 controlled, placing an emphasis on the role of energy flow as expressed in trophic level
 structure.

 Keever (1950) and Bormann (1953) based early successional theory on old field
succession in the North Carolina piedmont, studying passive revegetation of disturbed
lands. Then Egler (1954) discussed two separate models of succession. First, vegetation
is replaced in a set pattern by specific vegetation and resists outside invasion. Second,
the species that arrive first establish and remain on-site.