Geoscience Reference
In-Depth Information
EVERGREEN OAK FOREST
Sustainable
exploitation
Excessive exploitation
(cutting, burning, browsing)
Cutting, burning,
browsing
Grazing,
burning
MAQUIS
STEPPE/PASTURE
GARRIGUE
Cultivation,
irrigation
Field crops, orchards
Abandonment/regeneration
COMMERCIAL
AGRICULTURE
Exploitation/degeneration
may mean that it has never been suitable for trees. It is
clearly important in the light of these new studies to study
the ecological history and current ecological conditions
of each local area before accepting deforestation
unthinkingly across the entire region.
Adaptations to drought
The long summer drought means that plants must adapt
to a period of severe water stress at a time when air
temperatures are at a maximum. Xeromorphism or
adaptations to drought allow plants to survive these
adverse conditions in many and varied ways. Annuals are
ephemeral plants which grow only when conditions are
favourable, in the cooler and moister Mediterranean
winter. By germinating, growing, flowering, setting seed
and dying within one growing season these plants exhibit
the strategy of
drought avoidance
. Geophytes adopt a
similar pattern but grow from a bulb or corm which is the
vegetative resting stage after flowering, e.g. tulip, scilla,
asphodel.
Succulents
are able to store water in swollen
cells, e.g. cacti; a special group are halophytes, salt
tolerators such as salt marsh plants which can survive
saline soil conditions. Halophytes cope with salinity by
two mechanisms: filtering at the root surface, and
expelling salt at the leaf surface. The succulence is able to
near Valencia, Spain. Prominent plants are the carob, lentisc,
Kermes oak, buckthorn, euphorbia and, in the foreground, the
dwarf fan palm.
Photo: Ken Atkinson
