M. Vila et J. Terradas, EFFECTS OF COMPETITION AND DISTURBANCE ON THE RESPROUTING PERFORMANCEOF THE MEDITERRANEAN SHRUB ERICA-MULTIFLORA L (ERICACEAE), American journal of botany, 82(10), 1995, pp. 1241-1248
Two field experiments were designed to evaluate the importance of comp
etition, fire, repeated disturbance, and their interactions on the veg
etative and reproductive performance of the Mediterranean shrub Erica
multiflora over a 2.5-yr period. In a burn experiment, fire was applie
d to the ground-level stumps of previously clipped 13-yr-old plants wi
th a propane torch and competition was diminished by removal of neighb
oring plants. Fire resulted in a reduction of sprout vigor and biomass
of flowers; mature neighbors also reduced E. multiflora sprout vigor
and flowering. The interaction between fire and competition was nonsig
nificant. In a stand burned by a wildfire we studied the effects of re
generating neighbors on target plants by removing all neighbors or onl
y Quercus coccifera. the most dominant species in the burned stand. In
this stand we also simulated herbivory by repeatedly clipping the spr
outs of E. multiflora. Regenerating neighbors did not affect target pl
ant sprout vigor after the wildfire, but did cause a decrease in the b
iomass of flowers per plant. Survival decreased after repeated clippin
g but was not affected by neighborhood treatment. The results suggest
that the importance of competition on resprouting vigor was temporally
variable. Variables related to plant size rather than species determi
ned competitive superiority: resprouting neighbors did not affect resp
routing performance of target plants, but mature neighbors did. In nat
ure, fire may directly reduce vegetative and reproductive biomass by t
he heating effect. But it may have an indirect positive effect on biom
ass, by reducing competition among plants. Frequent disturbances that
removed aboveground biomass of E. multiflora had a detrimental effect
on target plant survival independent of neighborhood effect.