INVESTIGADORES
KITZBERGER Thomas
artículos
Título:
Effects of fire severity in a north Patagonian subalpine forest
Autor/es:
KITZBERGER, T.; RAFFAELE, E.; HEINEMANN, K.; MAZZARINO, M.J.
Revista:
JOURNAL OF VEGETATION SCIENCE
Editorial:
OPULUS PRESS
Referencias:
Año: 2005 vol. 16 p. 5 - 12
ISSN:
1100-9233
Resumen:
Question: What is the relative importance of fire-induced
canopy mortality, soil burning and post-fire herbivory on tree
seedling performance?
Location: Subalpine Nothofagus pumilio forests at Challhuaco
valley (41°13´S, 71°19´W), Nahuel Huapi National Park,
Argentina.
Methods: We fenced and transplanted soils of three burning
severities along a fire severity gradient produced by a fire in
1996. Over two growing seasons we monitored soil water,
direct incoming solar radiation, seedling survival, final seedling
total biomass and root/shoot ratio. Additionally, we assessed
severity-related changes in soil properties.
Results: Incoming radiation (an indicator of the amount of
canopy cover left by the fire) was the primary factor influencing
spring and summer top soil water availability, first and
second-year seedling survival and seedling growth. While
seedling survival and soil water content were negatively affected
by increased radiation, seedling final biomass was
highest in very open microsites. Burned soils showed lower
water holding capacity and soil carbon; however these changes
did not affect topsoil water, and, contrary to expectation, there
was a slight tendency toward higher seedling survival on more
heavily burned soils. Herbivory significantly reduced seedling
survival, but only under high-radiation conditions. While the
effect of radiation on final seedling biomass was not affected
by herbivory, R/S ratios were significantly reduced by herbivory
in high radiation microsites.
Conclusions: Despite inducing faster aerial growth, increased
radiation and herbivory in severely burned sites may effectively
prevent post-fire regeneration in north Patagonian
subalpine forest where seed sources are not limiting.