Vegetation, such as this cactus, are adapted to Loma El León’s scarce water conditions (Photo: Rodolfo Castillo)
The monument is found in the semiarid zone of Venezuela, which covers approximately 40,000 km², or a little less than 5% of the total area of the country and 67% of Lara State (Garcia et al., 1990; Ferrer, 1985). The prevailing harsh climate has brought about the emergence of very specialized flora and fauna species (Diaz, 1988; Alarcón & Diaz, 1993; Alarcón, 1990).
In the natural monument there is notable floral diversity and a unique combination of species. A preliminary listing of the flora in the monument includes a total of 116 species, of which, 81 are classified as shrubs, encompassing 77% of the shrub species found in the arid zones of Falcón and Lara States. The species are similar to the flora found at similar elevations in other Andean locations of the Sierra Portugesa (for example, in the villages between Sanare and El Tocuyo). While no endemic plants have been reported in the entire arid zone of Venezuela, in the semiarid zone of Loma El León there are five species endemic to the Lara State: Opuntia bisetosa (red-flowering prickly pear), Mimosa trinae, two undescribed species of the same genus, and one undescribed species of the Myrtaceae family. Additionally, other species abundant in the monument, including Cassia zygophilloides, Euphorbia lutzenbergii, and Cordia styermarkii, are only found in a few other locations in the country (Smith & Rivero, 1983; Garcia et al., 1990).
A very important characteristic of the vegetation is their root development, which occurs in surface soil horizons (above 50 cm), contributing to the physical stabilization of the soils and protecting the ecosystem against invasions of foreign species (Smith & Rivero, 1983). The plant communities include scrub brush (high, dense scrub brush; low, dense scrub brush; and sparse scrub brush), accompanied in some areas by patches of dry deciduous forest (approximately 40 ha) and savanna (approximately 70 ha) (García & Salazaar, not dated; García et al., 1990).
The high, dense scrub brush (193 ha) is mainly composed of primitive, perennial vegetation found on the eastern, wetter slopes of the hill; the dense stands of brush tend to be associated with amounts of precipitation greater than 700 mm. The tallest stratum of shrubs can reach a height of 3 to 4 m. However, the dominant species of shrubs are shorter, such as Lippia oreganoides, Calea berteroana, Wedelia calycina, and Croton argyrophyllus (Garcia & Salazar, not dated).
The low, dense scrub brush tends to dominate the northwestern and western sections of the monument. This stratum can reach a height of 2.5 m, and this community has a low density of thorny plants. The shrubs in this formation lose their leaves continuously throughout the year. The dominant species (including plants used commercially as condiments) have very soft, aromatic leaves that are occasionally consumed by goats. These shrubs have characteristics similar to plants found in the Mediterranean climates of California and Europe. Among the dominant species are Croton agryophylloides, Lippia micromera, Mimosa trinae, and Cordia steyermarkii. Of these, Lippia micromera has been designated as an invasive species in areas subject to fires. However, no clear evidence exists to support the hypothesis that this vegetation is a result of fire events (Garcia & Salazar, not dated).
The sparse scrub brush corresponds to the thorny plant communities that have been amply described in the arid zones of Venezuela., but thorny shrubs are not the dominant species of the sparse scrub brush found in Loma El León. The canopy coverage is markedly discontinuous in comparison to the dense brush formations. This formation tends to dominate on the dry northeastern slopes. The actual structure of the vegetation is very likely due to goat grazing in the area. Among the abundant species are Calea berteriana, Mimosa tenuflora, Casearia arguta, and Bunchosia cestrifolia (Garcia & Salazar, not dated).
The savanna formations found in the monument are not typical of the region. They are of secondary origin, most likely the product of repeated land burning and the establishment of pastures. Because they are secondary in origin, the savannas do not constitute a stable vegetation formation and are being progressively colonized by shrubs from the surrounding thickets. The most extensive savanna patch is found at the top of Loma, at 1,300 m ASL, in a zone exposed to strong winds and occasional light fog. In the lower stratum, Trachypogon spicata and other graminaes dominate, while there is also abundant Solanum karstenii and Polygala caracasana.
The golden trumpet tree (Tabebuia chrysantha), a species typical of dry forests and the national tree of Venezuela, dominates the existing patches of deciduous forest (Garcia & Salazar, not dated).
The natural monument is a very important refuge for fauna characteristic of the semiarid region of Venezuela (Smith & Rivero, 1983). The mammals found within include white-tailed deer (Odocoileus virginianus), armadillos (Dasypus novencinctus), collared peccaries (Tayassu tajacu), jagaurundi (Herpailurus yagouaroundi), gray foxes (Urocyon cinereargenteus), and margays (Leopardus wiedii). The monument also protects nesting sites for birds, including the well-known rufous-vented chachalaca (Ortalis ruficauda), the partridge, and eared dove (Zenaida auriculata). Additionally, the monument is located within the distribution areas of threatened species such as the black-hooded red siskin (Carduelis cucullata) and the dryland mouse opposum (Marmosa xerophila) (Garcia et al., 1990). The dryland mouse opposum is an endemic species of the dry forests of Colombia and Venezuela and is considered “insufficiently studied” (Rodríguez & Rojas-Suárez 1999); despite this lack of information, the dryland mouse opposum is classified on the World Conservation Union (IUCN) red list of threatened species as critically endangered.
The black-hooded red siskin (Carduelis cucullata) is a colorful red and black bird, considered one of the most endangered species in Venezuela. Its present distribution occupies only 20% of its former habitat. The bird is now restricted to relictual sites in the Lara-Falcón region and in Barinas. This diminished distribution has been attributed to the capture and commercialization of the species, especially for the purpose of breeding red canaries (Rodríguez and Rojas-Suárez, 1999). The species is specially protected by Resolution 438 published in the Official Gazette No. 32.619 (República de Venezuela, 1982). The black-hooded red siskin is also found in Appendix I of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES), which helped control trafficking of the species through Curazao, a country that served as a stop en route to Europe before subscribing to the aforementioned convention in 1987.
One of the dominant shrubs, the coastal plain creeping oxeye (Wedelia calycina), is favored by the black-hooded red siskin as a food source. Among some 44 other species whose fruit serve as nourishment for the bird in the wild, at least five are present in the monument: spleen amaranth (Amaranthus dubius), nodeweed (Synedrella nodiflora), black sage (Cordia curassavica), caperbush (Capparis spp.), and guinea grass (Panicum maximum) (Rivero, 1983). The presence of these species suggests that there are black-hooded red siskin in the area. Some authors indicate that Loma El León was, at one time, one of the most important habitats for the species (Smith and Rivero, 1983).