BATTAGLIA, L. L.* AND R. R. SHARITZ. Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802. - Hurricane disturbance increases spatial complexity of the environment: implications for regeneration patterns in floodplain forest communities.
In bottomland hardwood forests, hurricanes create a complex array of
flooding and light microsites that vary with intensity of disturbance.
Microsite heterogeneity may influence growth, species composition, and
spatial arrangement within the seedling and sapling layers, yet few
studies have addressed the combined effects of multiple environmental
factors and their spatial configuration on forest regeneration. In
the old-growth bottomland hardwood forest of the Congaree Swamp
National Monument, we established thirty 100 m2 plots
spanning a disturbance gradient created by Hurricane Hugo. We
measured relative elevation and estimated light availability based on
analyses of color fisheye photographs. Measurements and photographs
were taken at each woody seedling and at 25 random points within each
plot. To examine spatial patterns, we established two 200 cm
perpendicular transects at five of the random points in each plot and
took measurements and photographs at 5, 10, 25, 50, 100, 150, and 200
cm. Highly disturbed plots were more environmentally variable than
undisturbed ones, and seedlings occupied a relatively narrow range of
the variation present. Semivariograms indicated reduced spatial
autocorrelation of light and microtopography along the disturbance
gradient. The hurricane increased environmental heterogeneity which
has influenced spatial patterns of regeneration.
Key words: disturbance, heterogeneity, hurricane, light, microtopography, spatial patterns