Agriculture Reference
In-Depth Information
(a)
(b)
(c)
(d)
Fig. 6.7
Recently burned matorral near Bariloche, Argentina: (a) dominated by resprouting
Nothofagus antarctica
(b) with well-developed lignotuber and (c) postfire annuals not
evident in nearby unburned matorral, (d) including a species of
Phacelia
(erect with white
flowers), one of the dominant postfire annual genera in California chaparral. (Photos by
Jon Keeley.)
Disjunct patches of matorral shrublands occur under a MTC on the eastern side
of the Andes around Bariloche, Argentina, at around 41
S latitude and provide
some insight into the role of lightning. Some of these patches are dominated by
shrubs with well-developed lignotubers (
Fig. 6.7a
,
b
) and resprout after fire. More
importantly though, these communities have a number of annual forbs that
appear to be restricted to postfire sites (
Fig. 6.7c
,
d
), not unlike the ephemeral
postfire herbaceous flora in California chaparral (see
Chapter 5
); including
many of the same families: Hydrophyllaceae, Boraginaceae, Scrophulariaceae,
and Portulacaceae. This postfire flora is in striking contrast to the lack of such a
fire response in central Chile. It may be tied to the fact that the Andes are much
lower in this region and thus it is subjected to predictable natural lightning-ignited
fires, and that these shrublands are particularly prone to regular high-intensity
crown fires (Mermoz
et al.
2005
). Thus, these shrublands have had a far longer fire
regime than the anthropogenic fire regime of central Chile.