Agriculture Reference
In-Depth Information
Table 1.1 Vegetation comparisons between the five MTC regions of the world.
South
Africa
Mediterranean
a
California
b
Australia
c
Chile
Total vegetated
area (km
2
)
1 286 950
98 575
111 725
68 175
430 875
Grassland (%)
15
9
0
0
4
Shrubland (%)
d
45
34
79
97
63
Woodland (%)
25
35
8
2
27
Forest (%)
15
22
13
<
1
6
a
Due the extensive east-west range of the Mediterranean Basin there are some important
differences in vegetation; for example grasslands are a minor component of the western
basin but comprise 18% of the vegetation in the eastern basin, and shrublands follow an
opposite pattern.
b
Includes Baja California but not the northwest or Central Valley or higher elevations of
the Sierra Nevada.
c
In this topic the MTC in Australia is considered to include more forested landscape in
South Australia and Victoria than represented by these data. MTV further east in NSW is
dominated by forests.
d
Includes scrub and succulent associations.
Source
: From Underwood
et al
.(
2009
), modified for the Mediterranean Basin by MODIS
and CORINE remote imaging analysis (accessed Jan 2010).
Sclerophyllous vegetation dominant in MTC regions sometimes extends beyond
these climatic boundaries at similar latitudes, and it is preferable to refer to these
as mediterranean-type vegetation (MTV). For example, in most MTC regions the
evergreen sclerophyll shrublands extend eastward into regions with summer rains
(
Box 1.1
). In the past these have been referred to as mediterranean-type
ecosystems (MTEs), but this term should be avoided because generally the desig-
nation is based on the presence of MTV, and seldom do we have sufficient
information to confirm ecosystem similarities. When MTV outside of MTC
regions has been studied in detail, such vegetation often comprises ecosystems
that are rather different from those in MTC regions (e.g. Fotheringham
2009
). For
example, the same species of trees and shrubs may dominate MTV in both
summer drought and summer rain climatic regimes, but frequently the latter will
have an understory rich in C
4
grasses and the former will not. Thus, the focus in
this topic is on ecosystems in MTC regions with consideration of similar sclero-
phyllous MTV outside that climatic region when it can add to our understanding
of fire. Biogeographical patterns are very different from one region to the next. In
North America evergreen sclerophyll shrublands exist under the MTC of
California and many of the same MTV species occur disjunct 500 km eastward
in Arizona. Other pockets of MTV shrublands are found on well-drained sub-
strates in the southeastern part of the continent under an aseasonal rainfall
regime. Similar patterns are evident in the distribution of sclerophyllous-leaved
shrublands in southern Australia, dominating in the MTC region of Western
