Agriculture Reference
In-Depth Information
ecosystem responses to fire in the five MTC regions and related vegetation (MTV)
that often extends outside the MTC (
Box 1.2
).
Five MTC Regions
The largest MTC region is the Mediterranean Basin, which covers an expanse of
more than 3500 km
2
, with increases in summer aridity from north to south and
west to east (Que´ zel
1981
; Grove & Rackham
2001
). It includes portions of
Portugal, Spain, France, Italy, Greece and Turkey on the northern side of
the Mediterranean Sea, Morocco, Algeria and Tunisa on the southern side,
and at the eastern end of the basin Israel and adjacent parts of the Middle East.
This vast distribution across multiple ethnic regions has led to multiple names
applied to vegetation types. Evergreen broadleaf
matorral
,
maquis
,
macchia
and
garrigue
shrublands (
Fig. 1.6a
) transition on arid sites to a lower growing drought-
deciduous spiny formation known as
tomillares
,
phrygana
or
batha
. Geophytes are
common throughout the region and on disturbed sites there is a rich flora of
annuals. On arid sites low levels of disturbance are sufficient to displace shrub-
lands with annual grasslands.
Shrublands are dominated by evergreen sclerophyllous-leaved shrubs com-
monly differentiated based on their distribution on calcareous or non-calcareous
substrates. All of these taxa resprout after fire and some have well developed basal
lignotubers (see
Chapter 3
) and relatively few are postfire seeders (
Box 1.2
).
Evergreen woodlands of low broadleaf trees such as
Quercus ilex
,
Q. pyrenaica
and
Q. suber
(
Fig. 1.6b
), once widespread, still persist in more mesic sites. Conifer
forests of the moderate-sized serotinous-cone (see
Chapter 3
)
Pinus halapensis
are widespread throughout the northern side of the basin and sometimes replaced
at the eastern end of the basin by the closely related
P. brutia
. In addition, in the
western portion of the basin are populations of non-serotinous
P. nigra
,
P. pinea
and
P. sylvestris
.
Some forests such those dominated by
P. halapensis
typically burn in high-
intensity crown fires often associated with maquis fires, whereas others such as
P. nigra
or
Quercus pyrenacica
burn in understory surface fires. Due to the long
history of human civilization in this region, woodland distribution has greatly
contracted and it is often difficult to distinguish between natural pine stands and
plantations, some over 1000 years old (Grove & Rackham
2001
). This MTV
extends eastward into the summer-rain climate of eastern Turkey. Most wildland
fires are started by people, although lightning-ignited fires occur in most moun-
tainous regions of the basin (Va´ zquez & Moreno
1998
). Fires tend to be small due
to the extreme habitat fragmentation, although in southern France the frequent
foehn winds known locally as the mistral winds, or the meltemia winds of Greece
(
Box 1.3
), are capable of rapidly spreading fires over extensive portions of the
landscape.
