San Cristóbal-Casita

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San Cristóbal-Casita Volcanic Complex

The San Cristóbal-Casita Volcanic Complex is a protected area of 179.64 km2 under the category of Nature Reserve belonging to the National System of Protected Areas (SINAP) of the Republic of Nicaragua. It was established by Decree Law 1320 of 1983. It is located in the department of Chinandega, to the north of the Pacific region of Nicaragua, 130 km from the capital Managua. It is formed by a mountain range of five volcanic cones, among them volcano San Cristóbal, the highest of the country.

The mentioned Decree Law establishes in its article 1 that the creation of San Cristóbal-Casita Volcanic Complex Natural Reserve protected area aims to protect and prevent further ecological deterioration in those significant natural areas of our geography.

The San Cristóbal-Casita Volcanic Complex is a recharge area of the western aquifer. This aquifer is the source of supply of the entire battery of wells with which the National Company of Aqueducts and Sewers (ENACAL) supplies drinking water to the population of the municipalities of Chinandega, Chichigalpa, Posoltega, Corinto, El Realejo and El Viejo with about 340,000 inhabitants.

The aquifer also supplies water to all the rural communities located at the base of the volcanic complex, and to the irrigation systems of sugarcane factory San Antonio, which has the largest sugarcane plantations in the country.

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Location, Area and Access
The San Cristóbal-Casita Volcanic Complex Nature Reserve is located in the municipalities of Chinandega, Chichigalpa and Posoltega, Chinandega department, in the northern part of the Pacific region of Nicaragua, is part of the Maribios mountain range and has an extension territory of 17,964.10 hectares (179.64 km2) corresponding to 25,509 manzanas.

The limits of the Natural Reserve San Cristóbal-Casita Volcanic Complex are defined by the curve of level of 300 masl; which was established in his creative decree.

The soils of the protected area and the surrounding plains have volcanic origin, fertile and deep, with a sandy loam texture and extremely fragile.

The average precipitation on the complex is 1600 to 1800 mm annually (Atlas INETER, 1995), higher than in the rest of the Pacific region. This is because the area is influenced both by an axis of rainfall coming from the nearby Pacific Ocean and by the moist trade winds of the Caribbean Sea. Even in the high parts of the complex the precipitation is still much greater. A rain gauge installed 40 years ago in the farm Algeria, at 680 masl, shows average values of precipitation above 2000 mm per year.

There are no permanent water currents that descend from the complex due to the high porosity of their soils. However due to this high permeability the complex acts as an immense sponge that absorbs rainwater. This water is discharged in two ways: on one hand, it emerges in a series of short rivers that rise at a certain distance in the surrounding plains and flow into the Bay of Corinto and the Gulf of Fonseca; and on the other hand origins extensive groundwater mantles located in the plains to the north and south of the complex.

To the bay of Corinto run 10 rivers, several are dammed and used like source of water for irrigation. The most important are the river Posoltega, Mono Muerto, Amalia or Río Sucio, and Cosmapa, the latter runs close to the hacienda of the same name. Other rivers are the river Los Remedios, the Tesorero, Las Lajas, El Realejo, San Isidro and Atoya.

From this Nature Reserve is born the Olomega River which is one of the main headwaters of the Estero Real River. The Olomega flows to the foot of the hills of San Lucas located to the northeast of the cone of the Pelona, that at its mouth forms the protected area of Estero Real, declared Ramsar site.

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The Natural Reserve rises on the agricultural plains of western Nicaragua, forming a natural refuge in the midst of a highly humanized landscape. Its main characteristics are:

Diversity of ecosystems
In the protected area there are three types of natural ecosystems: dry tropical forest or deciduous forest, pine forest and savannahs without woody cover (natural pastures).

The Natural Reserve contains along with the Natural Reserves of Cosigüina and Chacocente, one of the last remnants of the tropical dry forest ecosystem that still at the beginning of the last century covered most of the Pacific region of Nicaragua. The tropical dry forest ecosystem occupies 42.34% of the total area of the Natural Reserve.

Likewise, the Pinus oocarpa stands of the complex, located mainly in San Cristóbal volcano and in the west edge of Casita volcano above 1000 masl, constitute one of the natural populations of pines located most to the south of the American continent. The 70.39 ha of pine forests in the protected area are threatened by the constant burning of the summer and the plague of the pine bark beetle, Dendroctonus frontalis Zimm.

The savannahs without woody cover (natural pastures) are the third natural ecosystem of the protected area. They occupy 11.36% of the area and are located on a substrate of volcanic lava and with little formed soil located in the summits of the volcano San Cristóbal, Casita, Moyotepe and La Pelona in heights above 600 masl. The herbaceous species occupy most of this ecosystem with Poaceae dominance. The savanna located on the slopes of San Cristóbal, above 800 masl, presents an interesting population of Liliaceae adapted to the strong winds and volcanic gases.

Another important ecosystem (agricultural) of the Reserve are coffee plantations, Coffea arabica. Because all the coffee in the Reserve is planted under the shade of trees, the coffee plantations form a valuable habitat for the fauna of the complex. The coffee plantations extend over an area of about 678.79 ha distributed among half a dozen coffee farms. They are planted in the highest parts of the complex where there is a greater risk of erosion, between 600 and 700 meters above sea level, and where they act as a protective barrier for the conservation of soils and waters. Coffee plantations also help to conserve natural forests since coffee owners are interested in leaving forests around them to help create a favorable microclimate for coffee plantations.

Species richness.

Flora and fauna.
There are few studies on the species of flora and fauna in the complex. The available information shows the following:

64 species of trees are reported in the Reserve according to a sampling carried out during an investigation carried out by the UCA (¿Forest and people can coexist? Túpac Barahona, Nitlapán 2002).

There are 61 tree species grouped in 34 families in Algeria farm, one of the largest private properties in the protected area and with a fairly conserved forest (Characterization of the arboreal vegetation of Casita volcano).

41 species of birds, 23 of mammals, 10 species of reptiles (Fundenic, 1999). 79 species of butterflies are reported in the Casita volcano (J.M.Maes, Revista Encuentro No. 51, 1999).

To date, at least 3 species of birds have been reported, in fact subspecies, restricted to habitats with isolated populations. These are: the dorsalist sabanero Aimophila botteri (vulcani); charralero of the rocks, Salpinctes obsoletus (fasciatus); and the Cejiblanco charralero, Thryothorus ludovicianus (albinucha). The latter according to Martinez Sánchez (The Cooper Ornithological Society, 1989) suggests a species different from that reported for the Yucatan peninsula, Mexico. The isolation of these species in the volcanoes makes them unique.

In San Cristóbal-Chonco, the occasional sighting of red macaws, Ara macao, belonging to the small population of macaws of the Cosigüina volcano is reported, indicating the presence of a corridor that connects both protected areas. The last reported sighting was in September 2003 at the San Rafael farm of the San Cristobal volcano at 700 masl. A couple of red limpets were observed in a jobo tree, Spondia bombin, then they went towards the sector of the Casita (personal communication of Don Vicente Perez, manager of San Rafael farm).

The area is a passage and feeding area for birds. The owner of the farm Algeria reports the presence of migratory birds that in November go down to bathe and feed in an artificial lagoon that is occupied as a watering hole for livestock on the property. It also reports the occasional passage of flocks between 20 to 30 individuals of toucans, Pteroglossus torquatus, in June-July.

Presence of populations and nesting areas of yellow parrot, Amazona ochrocephalla (auropalliata), in the San Cristóbal, Casita and Chonco volcanoes. Parrots build their nests on tall trees (+30 m) and mature so their presence is an indicator of the existence of old trees remaining in the primary forest.

Varied mammal fauna in farms San Rafael, San Cristóbal, Las Banderas, Miramar, Versalles, Santa Cruz, El Porvenir, Algeria, Bellavista and Concepcion. The presence of tigris, Leopardus wiedii; Sahinos, Tayassu tajacu; deer, Odocoileus virginianus; pizotes, Dasiprocta punctata; and guardatinajas, Agouti paca. It is reported in the Banderas and Miramar the presence of a population of 38 white-faced monkeys, Cebus capucinus.

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Potential of the Protected Area
Water and Forests
The main value of the San Cristóbal Volcanic Complex-Casita is the water. By its form, height and geographical position; the texture of its soils and agroforestry cover, the Natural Reserve acts like a giant sponge that absorbs the rain water and that later drains to the near aquifers and the sea, where it provides two great environmental services:

- Recharge of the aquifer of the West, from which all the drinking water is extracted for almost 340,000 people and serves as a base for the economic development of the municipalities of Chinandega, El Realejo, Chichigalpa, Corinto, Posoltega and part of the municipality of El Viejo.

- Maintenance of the mangroves of Corinto Bay and the wetlands of the Estero Real, Ramsar site. Both ecosystems receive a continuous supply of fresh water of subterranean origin that comes from the Natural Reserve. Without this contribution of fresh water both ecosystems would be exposed to a progressive salinization that could seriously alter their ecological balance.After water, the other great value of the Natural Reserve is its wealth of ecosystems, which is characterized by being one of the largest masses of dry tropical forest in the country with 7,676.36 hectares, and one of the last stands of pine forests, Pinus oocarpa, located more to the south of the American continent.

Critical areas
Planting of beans in San Cristóbal volcano
On the northwest slope of the volcano San Cristóbal, there is a zone of beans plantings, Phaseolus vulgaris, in an approximate area of 300 ha comprised between the heights of 500 to 640 masl.
This is a highly vulnerable area to landslides due to the combination of three triggers: fragile soil texture, high slope and no forest cover. The soils are sand to sandy loam, with slopes between 30 to 50% and with almost total absence of trees because the forest was cut down and replaced by bean crops.

Place damaged by the gases of the volcano San Cristóbal.
After its last eruption in the years 1684-85, San Cristóbal volcano was again active in 1971. From that year to date the volcano has continued to emit gases permanently.

Surface drainage network.
There is a dense network of superficial drainage that descends from the volcanic complex, for example only the road to the west of the protected area that joins the cities of Chinandega and Posoltega is crossed by 20 channels in a path of 13 km in length, that is to say more of one channel per kilometer.

The rainwater runoff rate is such that after heavy rainfall, a drop of water that falls in the high parts of the complex reaches the sea in less than 24 hours. In this way, large volumes of fertile soils are not lost without infiltrating large volumes of water, and when they reach the sea, they flood with mud the mangrove and breeding and spawning sites for fish, crustaceans and shrimp.

These large volumes of water, land and sand also destroy agricultural properties and soils located in the plains surrounding the protected area. The peanut planting areas located on the volcanic plain south of the volcanic complex are one of the crops most affected by sludge, stone and sand trawling.

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Assessment of biodiversity
Diversity of ecosystems
The San Cristóbal-Casita Volcanic Complex Nature Reserve is representative of three natural ecosystems: the only pine forests in the Pacific region of Nicaragua, dry tropical forest and grassy savannah without woody cover. From the point of view of their priority for conservation, the value of these ecosystems is as follows:

Ecosystem of Pines of the volcanic summits of San Cristóbal and Casita
The stands of pines, Pinus oocarpa (± 12º 30 'Norte, UTM 14) located on the volcanic slopes of San Cristóbal and Casita are part of the southern border of the Pinus genus in America, along with pine stands located on the Güisisil hill north of Lake Managua. This makes these pine forests a unique ecosystem in the world. Add to this their very small size (70.39 ha) and the threat they are being subjected to by the pest of the bark beetle and the summer burns, making this ecosystem the number one conservation priority for this protected area.

Dry tropical forest ecosystem
The tropical deciduous forest that is located along the protected area constitutes one of the last three great extensions of this ecosystem that still remain in the Pacific region of Nicaragua. Due to their medium size these forests do not face the same degree of threat of pine forests. However, because of the vital service they provide as protectors of the water infiltration capacity of 340,000 people and the environmental services they offer to Corinto mangroves and wetlands of the Estero Real, it is necessary to protect them to maintain and increase their coverage.

Savanna ecosystem without woody cover
This ecosystem is characteristic of the high parts of some of the volcanic quaternaries cones of the Pacific region such as the volcanoes Cosigüina, Telica, Hoyo, Masaya, Concepción. In the case of the San Cristóbal-Casita protected area, this ecosystem, due to its relative isolation and conservation in the heights of the volcanic summits, does not face the same risks of conservation of the pine forests and the dry tropical forest. These herbaceous savannas, made up of an important group of herbs introduced as the jaragua grass, Hyparrhenia rufa, play an important role as soil retainers in the high parts of the volcanic complex, where by the presence of strong winds tree species do not grow.

Diversity of species
San Cristóbal-Casita has less species richness than the other two large Natural Reserves of the dry tropic of the country, Chacocente and Cosigüina. However, it has particular species of conservation interest, including three groups of species: limited geographic distribution, endangered species, and endangered species. The species with limited geographic distribution are the following:
The Pinus oocarpa stands out first, the only pine in the Pacific dry tropics and the most "tropical" pine variety in the world.

Presence of three sub-species of birds restricted to habitat, these are: dorsilistado sabanero Aimophila botteri (vulcani); charralero of the rocks Salpinctes obsoletus (fasciatus) and the cejiblanco charralero Thryothorus ludovicianus (albinucha).

Four endangered species (Appendix No. 1, CITES). They are the following:
Mountain Cat, Leopardus wiedii. Leoncillo, Herpailirus yaguarondi. Yellow neck parrot, Amazon ochrocephala (auropalliata). Boa, Boa constrictor.

Fifteen species threatened with extinction (Appendix No. 2, CITES). They are the following:

Birds: Red-faced parrot, Amazona autumnalis, Cotorra, Amazona albifrons, Chocoyo zapoyolito, Brotogeris jugularis, Chocoyo orange front, Aratinga canicularis, Hawk of the rounds, Buteo magnirostri. Lechuza, Tyto alba.

Mammals: Sahino, Tayassu tajacu, white-faced monkey, Cebus capucinus.

Reptiles: Green iguana, Iguana iguana, Mica snake, Spiloteus pullatus, Rattlesnake, Crotalus durissus, Green Gallego, Basiliscus plumifrons, Brown Gallego, Basiliscus vitatus. Coral, Micrurus nigrocimtus. Plants: Pacific Mahogany, Switenia humilis.

Diversity of genes
The Natural Reserve is a gene bank and source of genetic variability of certain species of food importance and wood for construction, among which are the following:

It has some of the best cedar seedlings Cedrela odorata and maoba, Switenia humilis from Nicaragua located on the farms of Algeria and Bellavista on Casita volcano and El Porvenir farm on La Pelona hill.

Seedlings of pochote trees, Bombacopsis quinatum, on the eastern slopes of Chonco volcano. On the farm Las Banderas was the guanacaste tree, Enterolobium cyclocarpum, with the largest diameter of the country, about 3 meters at chest height.

A great variety of papaya, Carica peltata, that can be source and reserve of genes for the improvement of commercial varieties of papaya.

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Fragility analysis
Fragility or physical vulnerability implies the "degree of loss of an element or group of elements in the face of the probable occurrence of a disastrous event" (UNESCO / UNDRO, 1979). In the protected area the main natural riches are its ecosystems, groundwater and soils, and the most important events or threats occurring in the territory are fires, illegal logging, volcanic gases, insect pests, landslides.

Vulnerability Analysis
Vulnerability assessment measures the severity of potential threats based on known hazards and the level of vulnerability of the environment and society. A historical account shows that the protected area is a site prone to disasters because it has been affected by four major phenomena in the last 40 years. They are:

- 1962, violent mudslide of Chonco volcano on its western slope, there were no victims because at that time the area was uninhabited. A similar disaster today would destroy the settlements of La Joya and El Chonco that are nearby.

- 1971, restart of the volcanic activity of the volcano San Cristóbal, with potential danger for all the settlements of its surroundings. The volcanic gases are drying out the closed forests of the high parts of San Cristóbal.

- 1982, Hurricane Alleta is stationed for several days between León and Chinandega and causes serious damage to agricultural production and forests, and destruction of roads in the protected area.

- 1998, Hurricane Mitch and its intense rains cause a landslide in Casita volcano that buries the towns of Rolando Rodríguez and Augusto C. Sandino, killing about 2,000 people.

The high population density of municipalities of influence, the expansion of social and productive infrastructure and the impoverishment of the population over the last 20 years indicate that social vulnerability has increased. The same can be said of environmental vulnerability, as there has been a decline in protective forest cover due to fires, hurricanes and illegal cutting of firewood and timber.

On the other hand, despite its importance and high vulnerability, the area does not have risk analysis or identification of sites of high vulnerability, but only with a map of volcanic threats (INETER, 1995) on a very wide scale (1: 250,000) which is not useful for planning at the local level. However, the protected area and the communities in its buffer zone have local disaster prevention committees with radio communication equipment, training and assistance from SINAPRED.