Geology, soils and hydrology

Hispaniola forms together with Jamaica and Puerto Rico the northern part of the Caribbean Plate which is surrounded by the North American, the South American and the Cocos and Nazca Plates. The center of the Cordillera Central is part of three Antillean submarine arcs, trending from Yucatán and Honduras to Cuba and Jamaica reaching the Dominican Republic, proceeding to Puerto Rico and the Lesser Antillean Islands. These arcs have their origin in volcanic activities and plate tectonic movements of the above mentioned plates after the rup-ture of Pangaea in the early cretaceous period (CUCURULLO 1952). The magmatic center of the Cordillera Central was surrounded during the cretaceous period by flat seas with high se-dimentation activity of limestone. Acid intrusions took place between the late Cretaceous and early Eocene (LEWIS 1980). The material dissolved and was solidified to crystalline slate (WEYL 1966). Folding and elevation processes are dated to the Eocene/Oligocene and Pli-ocene/Pleistocene. Today crystalline slates, sediments and volcanics, peridotites and quartz diorites of the cretaceous period are found in the Cordillera Central. Besides the Cordillera Central and the Sierra del Seibo all other Dominican mountain ranges are composed of ter-tiary sediments (Figure II.3). The steep and narrow valleys of the Cordillera Central are wit-nesses of the tectonic activity of the humid tropics (KAPPAS & SCHÖGGL 2005). Along the southern border of Armando Bermúdez National Park the mountains are higher (for example Pico del Yaque 2,761 m a.s.l., Loma de la Viuda 2,801 m a.s.l., Loma La Rucilla 3,038 m a.s.l., Loma La Pelona 3,087 m a.s.l.) than in the north (Cerro de la Yucca 1,000 m a.s.l., Loma La Matica 1,107 m a.s.l., Cerro entre los Ríos 1,222 m a.s.l.) (Figure II.2). In the center, two high mountains are Loma del Tambor (2,621 m a.s.l.) and Loma de los Plati-cos (2,522 m a.s.l.). The altitudes in the western part of the national park are lower than in the east. Nearly all of Armando Bermúdez National Park is composed of magmatic rocks.

Glacial geomorphologic and sedimentary features near Loma de La Viuda and Alto de la Bandera like cirques, arêtes, glacial channels, roches moutonnêes, moraines, bog-filled de-pressions suggest the existence of glaciers and a snowline at 2,200-2,300 m a.s.l. during the Quaternary (SCHUBERT & MEDINA 1982).

FIGURE II.3. Geological structure of the Dominican Republic (Source: NUÑEZ MOLINA (1980) in BOLAY 1997:55)

Soils

The soils of Armando Bermúdez National Park are of the acid and little profound Ferralsol type (IUSS WORKING GROUP WRB 2007). Ferralsols are intensively weathered soils in the tropical and subtropical forests that occur on siliceous rocks such as siliceous tuffs and quartz diorites. Their color ranges from yellow to red. On the peaks and along the steep slopes (> 60%) the soils are highly eroded, poor in nutrients and rich in aluminum. The texture is variable with fine components, water retention capacity and fertility are low (MAY 2007).

These acid and weathered soils are just tolerated by a very specialized flora with a high amount of endemic plant species, sometimes of primitive character (LIOGIER 2000). Along the creeks and rivers the soils are less eroded and younger due to the transported mineral material of the fluvial sediments. They contain a higher proportion of nutrients, are less acid and their aluminum content is poor (MAY 2007). Soil color varies here between brown and black. A detailed soil map does not exist of the study area.

Hydrology

About 4,000 permanent and temporal streams run through the Dominican Republic. The sur-face water is used for energy generation, for industrial production, for irrigation and as drink-ing water. The Cordillera Central is the main water producer of the country. Therefore it is also called “Madre de las Aguas” (engl: mother of the waters). 709 rivers and creeks originate in the central mountain range, including Yaque del Norte River which rises in Armando Bermúdez National Park near Loma La Rucilla (SECRETARÍA DE ESTADO DE MEDIO A MBIEN-TE Y RECURSOS NATURALES 2004a). All of the rivers that originate in Armando Bermúdez National Park drain into Yaque del Norte River, mainly in the Valle de Cibao. Yaque del Norte River flows into the Atlantic ocean close to Monte Cristi and is with 201 km the longest river and the one with the largest catchment area. Due to the seasonal precipitation regime (see II.3.2 Climate), discharge volume varies throughout the year. For Yaque del Norte the maximum mean monthly discharge (1956-2001) measured at Pinar Quemado near Jarabacoa was of 14.6 m³/sec in May and minimum of 7.1 m³/sec in February (VICIOSO 2002 in GLEITSMANN 2005).

The catchment subsystem of Yaque del Norte River embarks 65 km² or 8.2% of the entire protected area (Figure II.4) and is divided in the two river systems Yaque del Norte and Los Guanos. Their confluence is near the village La Ciénaga at the eastern entrance of the national park. The catchment area of the subsystem of the Mao River in the extreme western part of Armando Bermúdez National Park has an extension of 273.6 km² (34.5%) (Figure II.4). It is composed of 11 rivers and creeks: Magua Arriba, Cedro, Magua al Medio, El Gallo, Sonador, Cenoví, Cenovicito, La Cidra, La Cidrita, Los Maitos and Mao. Mao River flows into Yaque del Norte River in the Valle de Cibao near the city of Valverde Mao.

Amina River has a catchment area of 112.5 km² covering 14.3 % of Armando Bermúdez Na-tional Park. The main tributaries of Amina River are Los Palos, Amina Arriba, Amina al Me-dio and La Manacla (Figure II.4). Amina River also discharges into Yaque del Norte River close to Valverde Mao. The Bao catchment area is with 338.6 km² (43%) the largest subsys-tem in Armando Bermúdez National Park. Bao River is also the longest (57.8 km) within the national park (Figure II.4). The water basin is divided in 11 micro catchment systems formed by the rivers and creeks Guanajumo, Jagua, Jamamu, de los Negros, Baito, Bao al Medio, Bao Arriba, La Guacarita, La Guacara, Las Lagunas and Antonsape Bueno. Bao River flows near Jánico in the Reservoir of Bao and is unified with Yaque del Norte River at Boca de Bao south of Santiago de los Caballeros.

FIGURE II.4. Hydrology in Armando Bermúdez National Park (Source: Boundaries of ABNP from Law 64-00; Catchment systems, villages, roads, rivers, dams from topographic maps 1:50,000, ICM 1983/1984 and field work)