Geoscience Reference
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winter is relatively dry. Temperature for a given
site and elevation varies little on average during
the year, although daily temperature may l uctu-
ate considerably. Semi-deciduous forest pre-
dominates at lower elevations on wet slopes,
and evergreen forest (bosque siempreverdes),
including cloud forest (bosque nublados), is
found from about 2000 m to 3000-3200 m alti-
tude (Ruiz 1992). Higher up is the alpine shrub
zone, known as páramo, an area described as
summer in the daytime and winter at night.
The term páramo is derived from Spanish,
generally referring to high, desolate, cold, wet
terrain (Luteyn 2011). Far from being desolate,
however, the páramo is now considered to be
the most diverse high-altitude ecosystem in the
world (Diazgranados 2009). It is situated in the
interval between the upper forest limit and per-
ennial snow cover in Colombia, Ecuador and
Venezuela. In the latter, páramo is found from
about 3500 m to 4500 m elevation mostly within
the Parque Nacional Sierra Nevada. This zone
is almost constantly in clouds. Rain falls most
days during the cool, wet summer season, and
snow falls during the slightly colder, dry winter
months. Wetland conditions are widespread in
formerly glaciated valleys and mesas, including
mires and wet meadows with histosols (Fig.
17-6).
The most characteristic plants in the páramo
are members of the subtribe (taxonomic
A
B
Figure 17-5. Climatic and environmental contrasts in
the Venezuelan Andes Mountains. A. Desert zone with
cactus vegetation in the Río Chama valley southwest of
Mérida, below 1000 m elevation. B. Alpine zone at Pico
Águila (4118 m), northeast of Mérida. P. Águila is a
horn shaped by glacial erosion of the mountain sides.
Photos by J.S. Aber.
Figure 17-6. Meandering stream courses through wet meadow in a fog-shrouded valley, Mesa del Caballos, Parque
Nacional Sierra Nevada, Venezuela. Photo by J.S. Aber.
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