Maracaibo
The Maracaibo dry forest is no exception to
the widespread degradation and conversion of
neotropical dry forests caused by agriculture
and grazing. The Maracaibo ecoregion falls
within the principal oil producing region of
Venezuela, which is one of its most degraded
regions.
Location and General Description
The Maracaibo dry forests are located in the northeastern coastal area of
Venezuela. The majority of the ecoregion is located in the state of Zulia in the
Maracaibo Basin; the remainder lies in the state of Trujillo. The ecoregion
borders the Sierra de Perijá to the west,
and the Cordillera de Mérida and the
Sierra of Baragua to the south and northeast respectively. There are also
patches of mangrove habitat interspersed along the shores of Maracaibo Lake, in the interior of the ecoregion. A major
network of roads extends through the basin; one of these roads is the Pan American
Highway. This area contains the Bolivar oil field, the largest field in Venezuela,
located on the northeastern shores of Lake Maracaibo. In fact, most of the oil in
Venezuela comes from around the oil fields in Lake Maracaibo (Harcourt and J.
Sayer 1996).
The entire ecoregion extends through coluvio-alluvial plains that range in elevation from 0 to
500 m. Annual temperature ranges from 16 to 26 oC. This area receives less than 1000mm of rain
annually and is strongly seasonal. The terrain is flat and the surrounding hills and mountains
become transitional moist forests at higher elevations. The area is traversed by rivers that flow
into the Maracaibo Basin from the surrounding mountains. The Palmar, Negro, Lora and
Catatumbo Rivers start in the Sierra de Perija. The Escalante River starts in the south Andes.
The Motatan, Misoa, and Pachango Rivers start east of the Maracaibo Basin (Venezuela 2000).
After fifty years of human intervention, little is left of the natural dry forests. The remaining
native vegetation consists of small isolated patches that include savannas with trees and
deciduous forests. Some of the species found in the fragmented savannas are Axonopus
canascens, Bowdichia virgilioides, Borreria sp., Byrsonima crassifolia, Bulbostylis capillaris,
Curatella americana, Copernicia tectorum, Galactia jussieuana, and Xylopia aromatica. Very
small fragmented areas of deciduous dry forests are found west of Lake Maracaibo. Some of the
flora in these areas include Acacia glamerosa, Bulnesia arborea, Bourreria cumanensis,
Copaifera venezuelana, Gyrocarpus americanus, Jacquinia pungens, Malpighia glabra,
Myrospermum frutescens, Piptadenia flava, and Ritterocereus griseus (Huber and Clara
Alarcon 1988). In abandoned areas, secondary vegetation includes Cecropia sp., Jacaranda
copaia, Xylopia aromatica, etc.
Biodiversity Features
Endemic terrestrial mammals characteristic of this ecoregion, and of others in dry
forests in Colombia and Venezuela, are the opossum (Marmosa xerophila), and the
vesper mouse (Calomys hummelincki). Marmosa is well adapted to dry habitats,
and is also found in deciduous forest, while the vesper mouse is mainly found in
sandy grasslands (Eisenberg 1989).
The number of endemic birds in this and other ecoregions is restricted to the small dry areas of
northern Venezuela, including the Maracaibo Basin. The following endemic birds are under the
status "least concern": the pygmy swift (Tachornis furcata), buffy hummingbird (Leucippus
fallax), chesnut piculet (Picumnus cinnamomeus), white-whiskered spinetail (Synallaxis
candei), black-backed antshrike (Sakesphorus melanonotus), slender-billd tyrannulet (Inezia
tenuirostris), tocuyo sparrow (Arremonops tocuyensis), and vermilion cardinal (Cardinalis
phoeniceus) (Stattersfield et al. 1998).
Current Status
There are few and very small natural habitats remaining due to the high population
and intensive land use in the ecoregion. Grazing has especially affected the
southeastern and southwestern areas of Lake Maracaibo (Huber and D. Frame
1988). The main impact on the natural vegetation has been caused by shifting
cultivation, and by an extensive network of roads surrounding Lake Maracaibo
(Huber n. d.). There are not any protected areas within this dry forest ecoregion.
Types and Severity of Threats
Continuous conversion of remaining natural habitat in the southern part of the Basin is
of great concern especially without any protected areas to keep any remnants of this
ecoregion safe from conversion. Also of concern to all living things of this ecoregion
is the recent findings that some of the rivers that traverse the Basin and flow into the
Maracaibo Lake, within this ecoregion, are polluted with pesticides and fertilizers
(Venezuela 2000). The greatest threat to this ecoregion unfortunately includes the
total destruction of this habitat type including all unique vegetation and fauna
associated with it.
Justification of Ecoregion Delineation
These are one of several dry forest regions of in the vicinity of the Maracaibo Basin
and Cordillera de Mérida. This ecoregion encompasses Lake Maracaibo, and
preliminary delineation’s follow Huber and Alarcon (1988). Linework was
subsequently reviewed and modified by Robert Smith (pers. comm), who identified
the region as unique based on species endemism and historic coverage’s.