Sierra de las Minas shelters 885 species of mammals, birds and reptiles, which represents 70% of the species registered in Guatemala and Belize (Nations et al., 1989). The different elevations and climate conditions in the protected area mean the mountain range operates similarly to the so-called "genetic evolution islands" (CECON, op. Cit) with a high presence of endemic species.
In the protected area, there are 21 species of regional endemic birds (Dix, op. Cit) and a high diversity of reptiles (Campbell, 1988). The cloud forest is an area with unique biological diversity (Dix, op. cit). Among the flora species, the threatened Hollywood lignum vitae (Guaiacum sanctum) exist in a severely fragmented population that is in serious decline (UICN, 1994). In the cloud forest, there is an enormous variety of endemic and threatened species.
According to the IUCN Red List (2001), Persea schiedeana, Quercus purulhana, Abies guatemalensis and Cornus disciflora are species at high risk of extinction, while Parathesis vulgata and Magnolia guatemalensis are classified as threatened species due to the collapse of their habitat. Taxus globosa is considered to be at low risk although it is close to being classified as vulnerable. The Pinus ayacahuite and Cupressus lusitanica are also regional endemic species and Agave minarum and Beaucarnea guatemalensis are local endemic species (Dfix, op. cit.). According to the CONAP Red List (2001a), the wild populations of Podocarpus oleifolius, Taxus globosa, Abies guatemalensis and Guaiacum sanctum cannot be used for scientific purposes.
The reserve also shelters species of fauna that are threatened and have restricted distribution. The cloud forest is the habitat of the Quetzal (Pharomachrus mocinno) and the horned guan (Oreophasis derbianus), two species that are protected along with the harpy eagle (Harpia harpya) , which is nearly extinct. These three species are highly threatened. There is also a significant presence of felines, including the jaguar (Panthera onca), puma (Felis concolor), onza (Herpailorus yagouaroundi), ocelot (Leopardus pardalis) and margay (Leopardus wiedii.) (FDN, 1997.) Other mammals include the red brocket (Mazama americana), the howler monkey (Alouatta palliata) and Baird's tapir (Tapirus bairdii) (UICN, 1997). Several of these mammals are included on the UICN Red List (2001), and the CONAP Red List (2001b) places the Baird's tapir (Tapirus bairdii) in serious risk of extinction.
According to the Dinerstein et al (1995) classification, the Sierra de las Minas ecological region is a Central American pine-oak forest. The protected area covers four of the life zones in the Holdridge classification (1987): dry forest, humid forest with pine and oak groves, cloud forest and summit forest.
The southern part of the protected area is one of the driest areas in Guatemala, with precipitation between 500 to 1,000 mm annually. Areas that have less precipitation are known as extremely hot semi-desert zones. Areas with greater precipitation are deciduous or semi-deciduous. Average temperatures vary between 24° C and 19° C, depending on altitude. Maximum temperatures can reach 40° C in the lowest areas.
In this area, the terrain tends to be rough and does not exceed 900 m above sea level. Vegetation depends on the aridity and composition of the soil. In the driest areas, the vegetation is low and sparsely distributed. This area is dominated by leguminous species.
Deciduous trees are found in some of the cooler areas. Species present in the ecosystem include: Gumbo limbo (Bursera simaruba), pochote (Ceiba aesculifolia), leucaena (Leucaena guatemalensis), Cochlospermum vitifolium, Gliricidia sepium, Pseudobombax ellipticum and oak (Quercus spp.) (Dix, 1993). Oak covers extensive areas, but occasional fires allow for large stands of pine to succeed in affected areas.
Humid forest with pine and oak groves
On the northeastern side of the reserve, below the cloud forest (below 1,000 m), there is a humid, warm forest receiving 2,000 mm of precipitation annually. Caribbean pine groves, Curatella Americana and Oak (Quercus spp), grow on the hillsides (Dix, op. Cit). Below 1,000 m and west of the Sierra, the forest is drier and characterized by oak groves (Quercus spp.), Oocarp pine (Pinus oocarpa) and Evergreen Alder (Alnus jorullensis).
In the western areas of Sierra de las Minas, there are pine and oak groves between 1,000 and 1,200 m. Dominant species are: Quercus spp. Patula pine (Pinus patula), (Tecunumanii), Oocarp pine (P. oocarpa.), sweet gum (Liquidambar styraciflua) and maple (Acer skutchii). This is another region where fires have resulted in monocultures of pines (Secaira et al, 2000).
The cloud forest, which has faced little or no intervention, covers approximately 130,000 ha of the protected area, with the majority in the nuclear zone (FDN, 1997). It includes a variety of different altitudes. On the northeastern hillsides, the forest falls below 1,000 m and in the south areas reach higher than 1,900 m (Dix, 1993). The area is marked by ravines and gullies with very pronounced slopes. The bio-temperature exceeds 20° C in the low areas, while in the high reaches it is closer to 11° C. The more humid northeastern areas receive around 4,000 mm annually; while in the driest areas receive 1,500 mm. The flora composition varies depending on the altitude and the orientation.
Between 1,500 and 2,700 m, the forest is dense with well-developed trees that reach a height of up to 35 m. Broad leaf species predominate. They are characterized by a wide, dense canopy with robust trunks supporting abundant branches in the high reaches. There is limited sunlight below the canopy, and in combination with the humidity, this gives rise to a thick carpet of moss sometimes dozens of centimeters thick.
The superior level, 30 - 35 m, is dominated by oaks (Quercus spp.), Perseas (Persea donnell-smithii, P. sessilis, P. schiedeana, P. vesticula), magnolia (Magnolia guatemalensis), Podocarpus oleifolius, Alfaroa costarricensis, Billia hippocastrum, Brunellia mexicana (Dix, op. cit.), Phoebe bourgeauviana, Cornus disciflora, Dendropanax oliganthus y Parathesis vulgata (CDC, 1993). Depending on the situation, tree communities are also dominated by Quercus spp., Persea sessilis, and Podocarpus oleifolius, or Quercus spp., Quercus sapotaefolia and Persea vesticula.
Between 2,400 (CONAP/INAB, 1999) and 2,900 m, (CDC, op. Cit), many parts of the forest are dominated by oak (Quercus spp.) and conifers. The lowest temperatures fall below 0° C between December and March. The upper canopy reaches 35 m.
In this area, the Guatemalan fir (Abies guatemalensis) makes up 21% (CONAP/INAB, op. cit.) of the forest, and there is less diversity in tree species than at lower altitudes (CDC, op. Cit.). Quercus spp is found along with white pine (Pinus ayacahuite), (Taxus globosa) (Dix, op. cit.), cypress (Cupressus lusitanica) (CONAP/INAB, op. cit.), Pinus pseudostrobus (CDC, op. cit.) and Abies guatemalensis.
Above 2,500 m in areas exposed to harsh climate conditions, the flora community is dominated by bushes and stocky trees. They rarely grow higher than eight meters. Dominant species include Pinus pseudostrobus, P. Ayacahuite, Quercus spp. and Podocarpus oleifolius. The tree stratum, up to two meters high, is extremely dense and dominated by ericaceous, with a presence of rhamnaceous, theaceous and agavaceous (CDC, op. Cit).