PARENT SESSION
Oral Session #17: Wetland Ecology. Presiding: E. Weiher.
Monday, August 6, 2001. 1:00 PM to 4:15 PM. Hall of Ideas H.
Developing appropriate plant assemblage bioindicators of forested wetland hydrology.
Volin, John1, Owen, Dianne1, Dunson, William2, 1 2
ABSTRACT- Vegetation assemblages are proposed as bioindicators of the status of, and changes in, wetland hydroperiod for the Big Cypress region of the Florida Everglades. Wetlands with diminished hydroperiods will contain either or both (1) inappropriate assemblages of inundation-intolerant plant species, or (2) inundation-tolerant plant species in wetland zones that normally would have a hydroperiod too long for their survival. This is the result of a colonization shift of plant species from higher to lower elevations as wetland hydroperiods are shortened by anthropogenic activities. The shift is most obvious when the canopy contains a substantial proportion of long-lived cypress trees, which clearly indicates the prior wetter hydrological status. Within each vegetation stratum or layer, an assemblage of plant species is chosen to represent a three-step gradient in tolerance to inundation. In this way an observer can assign a relative value (from high to low in three levels) for hydroperiod of a site simply by examining the present vegetation. A comparison between the present hydroperiod thus estimated and the likely historic or desired hydroperiod will determine the degree and type of restoration needed, or the success of restoration undertaken. Data testing this proposed vegetation assemblage bioindicator model will be presented.
KEY WORDS: bioindicator, restoration, wetland, hydrology