Cordillera de la Costa
This region is located in elevational patches
between middle and high elevations along the
Venezuelan northern coastal range mountains (between 600 –2675 m in the
high summits),
and supports extraordinarily diverse montane evergreen forests. Separated
physically from
the Andes by the Yaracuy depression, and from the forests of the Guyanan
floristic
province by the extensive plains of the Andes (llanos), these mountains
are isolated from one
another by much drier surroundings lowlands. Isolation and a great variety
of
physiographical scenarios, have created an extraordinary species richness
and strong
speciation processes that are manifested in a relative high level of plant
and animal
endemism.
Location and General Description
The Cordillera de la Costa montane forests are located in the northern
coastal range
of Venezuela. The ecoregion is composed of various enclaves that range
from
approximately 600 to 2675 masl. The Cordillera de la Costa, or Costa
mountain
range, is separated from the Andes by the Yaracuy depression, and from the
southern forests of the Guyanan floristic province by the extensive
Llanos. The
montane forests are isolated from one another by xeric vegetation.
The Cordillera de Costa extends 720 km from east to west along the
northern coast of Venezuela.
The western section of the Cordillera lies in the state of Yaracuy, where
the depression of the
Yaracuy River forms a natural southwestward separation. Two main portions
of the western
Cordillera de la Costa are usually recognized, the Serranía del Litoral
in the northern mountain
range along the coastline of the Caribbean Sea, and the Serranía del
Interior south of Valencia
lake and the valleys of Caracas. The most important mountains of the
Serranía del Litoral are the
Avila (2200 m), La Silla de Caracas (2650 m), and Pico Naiguatá (2675 m,
the highest peak of the
entire cordillera) located northeast of Caracas. Pico Codazi (2200 m),
near Colonia Tovar, and
mountains of Rancho Grande are located to the north of Maracay City. The
Serranía del Interior
includes Cerro Platillón (1930 m), and the mountains of Guatopo (1800 m).
The eastern section of
the Cordillera de la Costa, includes the mountainous areas east of Bergantín
and those around
Caripe, with a maximum elevation of 2596 m at Cerro Turimiquire and the
mountain range of the
Paria Peninsula. This Peninsula has two high peaks with montane forests:
Cerro Humo (1350 m)
and Cerro Patao (1048 m).
The Cordillera de la Costa, formed during the Tertiary period, is older
than the Andes. This
mountain range started be lifted by tectonic movement during the upper
Cretaceous period, and
attained its present configuration with an orientation from west to east
(Steyermark 1979). The
Cordillera de la Costa consists mainly of schist and gneisses, underlain
in some parts by
granites; also limestones are present in several areas, especially in the
Serranía del Interior, were
the Morros de San Juan offer a characteristic landscape feature (Huber,
1997). The calize rocks
in the proximity’s of Caripe have originated the Guácharo cave, the
most famous karstic
formation of Venezuela (PDVSA 1995). Soils are generally acidic and
predominantly entisols and
ultisols; nutrient levels are generally low with exception of certain
soils localized in the valleys
around Valencia lake (Huber and Frame 1989).
The climate of the Cordillera de la Costa is strongly influenced by the
north-eastern trade winds,
specially during the dry season from December to April, whereas during the
rainy season the
Intertropical Convergence Zone (ITCZ) reaches its northern winds with high
moisture. In the
montane forest, the climate consists of prehumid mesothermic conditions
(average annual
temperature 10°–20° C and rainfall between 1000–3000 mm). Frequent
mist occurs above about
800 m on the windward, and 1000 m on the leeward slopes, and it extends up
to 1000–1200 m
(Huber 1997).
According to Huber (1997), this ecoregion includes three forest types:
evergreen transition
forests, evergreen montane cloud forests, and upper montane elfin forest.
Evergreen transition
forests, ranging from 600 to 900 m, form a narrow belt between the lower
montane
semideciduous forests and upper montane forests, or ever green montane
cloud forest. Here the
giant endemic Gyranthera caribensis (up to 60 m tall) form small stands
emerging above the
general forest canopy dominate by Trophis racemosa, Ficus macbridei,
Tetragastris
caracasana, Zanthoxylum ocumarense, Banara nitida, etc. The understory is
dominated by
shrubs of Aphelandra micans, Besleria disgrega, Psycotria macrophylla and
Hoffmannia
apodantha, together with large colonies of giant herbs such as Musaceae
(Heliconia bihai, H.
revoluta), Araceae (Dieffenbachia maculata), Marantaceae, and many ferns.
Evergreen montane cloud forests, extending from 1000 to 2200 m, are the
most species-rich plant
communities of the entire Cordillera de la Costa. They are irregularly
structured in 2–3 canopy
layers with a main canopy extending up to 15–20 m. Canopy trees include
Ecclinusa
abbreviata, Graffenrieda latifolia and Ocotea spp. Palms are very frequent
in the canopy and
in the understory as well, either growing solitarily (Dictyocarium sp.,
Socratea sp., Geonoma
spp.) or in large, sometimes monodominant clumps (Hyospathe pittieri,
Catoblastus
praemorsus, Bactris sp.). Epiphytes (ferns, orchids, bromeliads, ericads
and gesneriads) and
terrestrial ferns are very abundant, and shrub and herb layer is usually
dense and dominated by
endemic species.
Upper montane elfin forest and scrub, resembling in some instances the
sub-paramo belt of the
Andes, is found above 2000–2400 m. Here, the open scrub is dominated by
the primitive
espeletioid composite, Libanothamnus neriifolius, and show an irregular
but often rather dense
herbaceous layer; while in the low mossy forest the trees Clusia
multiflora, Weinmannia spp.
and Prumnopitys harmsiana, are the most frequent.
This general pattern in the distribution of vegetation due to elevation is
common in most of the
mountains of the Cordillera de la Costa. In some regions, such as the
mountains of the
Peninsula of Paria, exposure to the prevailing winds makes strong
modifications in the local
conditions of humidity and temperature, allowing lower montane evergreen
forests to start at
400 m above sea level (Moore and Beament 1989; Stattersfield et al 1998).
Other examples are the
modifications in the vegetation patterns present in the slopes of the
mountains of El Ávila
National Park, and other mountains of the region, where the original
forest vegetation had been
substituted by open vegetation, like savannas, that display a strong
component of exotic
grasses (Huber et al 1998).
Biodiversity Features
The Cordillera de la Costa montane forests are rich in species and are
considered
the most important endemic zones for flora and fauna in Venezuela. It
would appear
that the primary factor for determining this grade of endemism is mainly
related to the
establishment of topographic barriers that separate the Cordillera de la
Costa with
these other two mountainous systems (Steyermark 1979).
Phytogeographycally, the flora of the Cordillera de la Costa shows a
stronger relationships with
the Mesoamerican and Caribbean floristic regions than with the northern
Andean flora (Huber,
1997) and the Guayanan flora (Steyermark 1979). A survey of endemic plant
species registered a
total of 247. According to this survey, the dispersal centers of the two
cordilleras (western and
eastern) showing the greatest number of endemic species are Naiguatá with
69 species, Rancho
Grande with 40, Guácharo (Caripe) with 38, Turimiquire with 37, and Paria
with 29 (Steyermark
1979). However, other botanical studies have shown important differences
in the values of
endemism for the same areas (see Huber et al, 1998), revealing the need
for more botanical
research to have better estimates of endemic species.
Endemic birds in the Cordillera de la Costa are also relevant. A total of
12 bird species are
restricted to the entire ecoregion (Table 1) Five of them are exclusive of
the western cordillera,
and another five to the eastern cordillera, with two species common to
both
sections(Stattersfield et al 1998). The eastern Cordillera also includes
45 endemic subspecies, 13
of which are confined to the Paria peninsula (Cracraft 1985). The number
of Andean-derived
bird species in the various coastal mountain ranges decreases from west to
east, with the
minimum number in the Paria Peninsula. (Moore and Beament, 1989). All the
eastern region
endemic birds are considered threatened species. The scissor-tailed
hummingbird (Hylonimpha
macrocerca), paria whitestart (Myioborus pariae), Venezuelan
flower-piercer (Diglosa
venezuelensis), and grey-headed warbler (Basileuterus griseiceps) are in
critical danger, and
white-throated barbtail (Premnoplex tatei) is endangered. In the western
portion the endemic
rusty-flanked crake (Laterallus levraudi) and the northern helmeted
curassow (Pauxi pauxi),
common to other ecoregions, are vulnerable and endangered respectively
(Stattersfield et al
1998). Other non-endemic bird distributed along the western region of the
Cordillera, such as
the harpy eagle (Harpia harpia) and the military macaw (Ara militaris),
are considered
vulnerable at national level (Rodriguez and Rojas-Surarez 1997).
Bird migration from north and south has been registered during boreal
autumn (Aug-Oct) and
spring (March-April) in Henri Pittier National Park (Zalles and Bildstein
2000). The Peregrine
falcon (Falco peregrinus) and the broad-winged Hawk (Buteo platypterus)
have been observed
during the last 10 years at Paso Periquito located in the lowest point of
the mountain range.
Eighteen other migrant species have been registered during this time
(Salas et al, 2000).
The ecoregion has one endemic mammal registered, Ichtyomys pittieri- a
fish-eating rat,
confined to the western region of the cordillera (Linares 1998). There are
also four insectivore
non-endemic species of bats (Thyroptera discifera, Myotis keaysi, Molossus
bondae, y
Tadarida aurispinosa) that are found in other neotropical regions
excluding Venezuela (Linares
1998).
There is not enough information about the herpetofauna of the Cordillera
de la Costa. The
existent available information is based on isolated captures, so the
number of specimens and
ecological data of many species is insufficient. Although more studies on
the herpetofauna are
necessary, the Cordillera de la Costa Montane Forests is considered as a
region with great
endemism. At least 21 species of frogs and 11 species of reptiles are
recognized to be endemic
to this region (Table 1). The endemic frog, Atelopus cruciger, was once
abundant in the cloud
forests of the Cordillera de La Costa. Today this amphibian is the first
frog declared endangered
in Venezuela (Manzanilla et al, 1995; La Marca and Lotters, 1997). The
frog has disappeared
from protected areas like Henri Pittier and San Esteban parks (last
registered in the late 80s). The
fast decline in its population has been related to the global decline of
amphibians (Rodriguez
and Rojas-Suarez, 1995), and specifically to the decline of other species
of Atelopus in the
Andes.
Current Status
The remaining fragmented montane forests are restricted to higher
elevations, where
the pronounced slopes are difficult to access (Huber, 1997). The ecoregion
includes11 National Parks: Yurubí of 237 km2 (IUCN category II), Henri
Pittier of
1,225 km2 (IUCN category II), San Esteban of 435 km2 (IUCN category II),
El
Avila of 852 km2 (IUCN category II), Macarao of 150 km2, Guatopo of 1,225
km2, El Guacharo of 627 km2 (IUCN category II), Peninsula de Paria of 375
km2
(IUCN category II), and five Natural Monuments: Pico Codazi of 119 km2
(IUCN
category III), Cueva Alfredo Jahn of 0.6 km2 (IUCN category III),
Alejandro
Humbolt of 1.8 km2 (IUCN category III), Juan Germán Rocio o Cerro
Platillon of
80 km2 (IUCN category III), and Morros de Macaira of 1 km2 (IUCN category
III). Governmental protection is deficient, and most of the protected
areas are
threatened (even National Parks), except for El Avila, Henri Pittier and
Pico Codazi
(Huber 1996).
Types and Severity of Threats
Deforestation due to shifting cultivation has been responsible for most of
the
destruction of the original forests on the lower and middle mountain
slopes. One of
the areas most heavily affected by shifting cultivation is the Cerro
Turimiquire and the
Cerro Peonía in the eastern section (Wege and Long, 1995). Likewise, the
lower
montane forests of Peninsula de Paria, where habitat destruction is still
proceeding at
an alarming rate (Long, 1995), are being altered and settled following the
completion
of a road leading to Macuro (Huber and Frame 1989). Deforestation in other
areas
is also caused by construction of tourist and recreation resorts in the
vicinity of the
larger cities, which also involves intensive road building into previously
inaccessible
areas (Huber 1997).
A major threat to the remaining forests are frequent fires lit during the
dry season in the already
deforested and mostly savanna-covered, surrounding lower areas. Although
fires usually do
not penetrate into the cloud forest itself, in some place the adjacent
montane evergreen forests
are being severely reduced (Huber 1997).
Another important threat is the selective extraction of some plant species
of commercial value.
Even though no known Venezuelan plant species has yet been exterminated,
some of them are
certainly either endangered or threatened. This is especially true for
some species of orchids of
genus Oncidium, Cycnoches, Schomburgkia, Brassavola, Encyclia, Lycaste
(Huber 1998)
many species of Catteya and the species Masdevallia tovarencis (endemic of
the central
portion of the Cordillera de la Costa) (Steyermark 1977). Also tree ferns,
whose trunks are made
into hanging baskets to grow orchids, are in great demand (Steyermark
1977).
Finally, shifting hunting and presence of great number of introduced
animals that feed in small
mammals and birds, are also an important threat to the fauna. This
situation especially occurs in
those areas that are located near populated areas (Fernandez-Badillo and
Ulloa 1990).
Justification of Ecoregion Delineation
These patches of montane forest occur in a mosaic of xeric habitats which
predominate northern Venezuela, and are therefore refuges for many species
–
including a high percentage of endemic species (Stattersfield et al.
1998).
Delineation’s were derived from Huber (1988), and linework was modified
following
the expert opinion of Smith (pers. comm), whose extensive experience in
the area
help make critical distinctions between original and current vegetation
cover. This
archipelago of moist forests are generally characterized by distinct
elevational
changes, creating a gradient in climate and therefor flora and fauna