Revista Chilena de Historia Natural 85 (1): 101-111, 2012
RESEARCH ARTICLE
The effect of heat and smoke on the emergence of exotic and native seedlings in
a Mediterranean fire-free matorral of central Chile
We studied the effect of heat shock and wood-fueled smoke on the emergence
of native and exotic plant species in soil samples obtained in an evergreen matorral of central Chile that has been free of
fire for decades. It is located on the eastern foothills of the Andes Range in San Carlos de Apoquindo. Immediately after
collection samples were dried and stored under laboratory conditions. For each two transect, ten samples were randomly
chosen, and one of the following treatments was applied: (1) heat-shock treatment, (2) plant-produced smoke treatment, (3)
combined heat-and-smoke treatment, and (4) control, corresponding to samples not subjected to treatment. Twenty-seven
species, representing 13 families, emerged from the soil samples. The most abundant families were Asteraceae and
Poaceae. All of the emerged species were herbaceous, and 18 species were exotic. Respect to general hypothesis, there is
no evidence for the proposition that fire-free matorral has lower proportion of exotic and native species with fire-related
cues than matorral with fires. Among the exotic and native, the mean number of species that emerged from soil samples
did not change significantly with respect to the control for any of the treatments applied. Nevertheless, important species-
specific responses were observed. Smoke and heat-smoke combination significantly increased the emergence of the exotic
species Anthriscus caucalis. While smoke-related cues significantly increased the emergence of the exotic
species Avena barbata, the emergence of the exotic Aphanes arvensis and the native Bromus
berteroanus decreases. For several species our results showed inconsistent responses to fire-related cues compared to
those reported in the literature. We suggest that these differences might be related with the fire-history in the populations,
an important issue poorly acknowledge in the literature.
Key words:
central Chile,
exotic herb, fi re, heat-shock, smoke
