B. Beckage et Ij. Stout, Effects of repeated burning on species richness in a Florida pine savanna:A test of the intermediate disturbance hypothesis, J VEG SCI, 11(1), 2000, pp. 113-122
We studied the effect of burning frequency on the density and species richn
ess of understory flowering stems in a Florida sandhill. Flowering stems we
re censused weekly for 54 weeks in six sites that had been burned one to si
x times in the previous 16 years. We concurrently measured overstory charac
teristics such as species composition, density and basal area. We used maxi
mum likelihood and Akaike's Information Criterion to compare linear, quadra
tic, saturating, and null models of community response to repeating burning
. We did not find a relationship between species richness, diversity or flo
wering stem density and fire frequency. Tree density was related to fire fr
equency and may represent an indirect pathway for fire effects on understor
y characteristics. While we found no support for the Intermediate Disturban
ce Hypothesis, an analysis of our experimental design indicated that we had
low statistical power. We develop the hypothesis that a saturating model o
f response to fire best describes understory species richness in our system
. We test this hypothesis using the most extensive published fire data set
we are aware of and find support for a saturating model.