The Guanacaste Conservation Area (GCA) is manager as a single unit divided into sectors or sections which include biological stations and one experimental forest station. Each section is the responsibility of an administrator. Santa Rosa and Guanacaste parks are made up of the following 9 sections: Santa Rosa, Naranjo; Murciélago, Islas Murciélago, Pocosol, El hacha, Pitilla, Orosí and Cacao.
Most of these two parks lies within the Santa Rosa Plateau, which is a result of deposits from glowing cloud eruptions 3-4 million years old, and which corresponds to the climatic region known as Dry Pacific. Some of the most recognizable habitats found here are: old grasslands, sparsely covered in jaragua grass (Hyparrhenia rufa) from Africa and dotted with several species of pioneer trees, such as the rough-leaf tree (Curatella americana), which will end up eliminating the grassland; deciduous woodland with some 240 species of trees and bushes, including the ear tree (Enterolobium cyclocarpum), - which is the national tree - , rosewood (Dalbergia retusa), the threatened mahogany (Swietenia marcophylla) and Ateleia herbert-smithii, which is only known from Santa Rosa Park; forests of evergreen oak (Quercus oleoides), evergreen forests and riverside woodland where the locust (Hymenaea courbaril) and the cow tree (Brosimum alicastrum); are found; the mezquite-nacascol swamps (Prosopis juliflora-Caesalpinia coriaria); very thorny stunted forests where agaves and cacti occur; beach vegetation, and mangrove swamps with species of red mangrove (Rhizophora mangle) and black mangrove (Avicennia germinans).
There is rich and varied animal life in this variety of habitats. Both the dry forest and the rest of the GCA, 115 species of mammals, more than half of which are bats, have been recorded. Some of the most conspicuous are the white-tailed deer (Odocoileus virginianus), the white-nosed coati (Nasua narica) and the howler monkey (Alouatte palliata). What is more, there are around 300 species of birds, such as the magpie jay (Calocitta formosa), the orange-fronted parakeet (Aratinga canicularis) and common black hawk (Buteogallus anthracinus), around 100 amphibians and reptile species. It is estimated that there may be over 30,000 species of insects, including over 5,000 species of moths and butterflies.
The beautiful beaches of Naranjo and Nancite are important laying sites for sea turtles, mainly olive ridley (Lepidochelys olivacea), leatherback turtles (Dermochelys coriacea) - the biggest of all - and Pacific Green Turtles (Chelonia agassizi). Nancite is home of the largest laying-grounds of olive ridley turtles in all of Tropical America. There is a biological station there. Other abundant species on the beaches are clams (Donax sp.), snails (Olivella sp.) and crabs, such as Ocypode gaudichaudii, Uca sp., Coenobita compressa , Jaiba Callinectes arcutus and Emerita sp..
On the rocky coasts along the Santa Elena Peninsula there are green algae (Enteromorpha spp.), molluscs like the limpet (Siphonaria gigas) chitons (Chiton stokesii), and echinoderms, such as sea cucumbers (Holothuria sp.). Naranjo beach offers ideal conditions for surfing.
The Santa Rosa sector is one of the historically most important areas in Costa Rica. The Historical Museum of La Casona and the stone corrals that can be admired there date from the colonial period and was the scene of the battle on March 20th, 1856 against the filibusters in defence of national sovereignty.
The Santa Elena Peninsula is the oldest and driest area of the country. It is an outcrop of peridotite, an intrusive igneous rock, which, in this case, is about 85 million years old. Bolanos Island, situated north of this peninsula and part of Santa Rosa park, is an 81 m high oval rock of irregular topography situated 1.5 km from the coast of Descartes Point.
This island is especially important for bird conservation since it protects one of the few areas known in the country where colonies of brown pelicans (Pelecanus occidentalis), numbering 500 to 600 birds, nest among the scarce vegetation. This is the only known nesting site of magnificent frigate birds (Fregata magnificens), with around 1,000 birds, and of American oystercatchers (Haematopus palliatus).
Guanacaste National Park contains the Cacao, Maritza and Pitilla biological stations. Cacao Biological Station lies on lower slopes of this 1,659 metre-high volcano. El Cacao is a stratovolcano that has been inactive for thousands of years. In this massif there are wet evergreen forests and cloud forests of thick vegetation with an abundance of orchids and ferns. The station is situated at 1,000 m, and is equipped to accommodate up to 30 people. It has drinking water and radio communication, and the access is restricted. This site is 51 km from Liberia via Panamerican Highway - Quebrada Grande - Gongora on roads that are partly asphalted and partly earth. From the station there are path leading to El Pedregal, to the top of the volcano and to the Maritza Station. There is a bus service between Liberia and Quebrada Grande. In the latter town there are grocery stores.
The Maritza Biological Station is situated on the lower slopes of the 1,446 m high Orosi Volcano. The Orosi is is a well developed conical stratovolcano with a very worn crater that has not been active for hundreds or thousands of years. The lower slopes of this massif are totally covered in very dense moist forest and cloud forest, and in the lowest parts there are dry and gallery forests. One of the longest and most important rivers in Costa Rica, the river Tempisque, rises in this massif. It is source of water for irrigation.
The area known as El Pedregal, closet o the station, is of great cultural interest and it is possible to see hundreds of petroglyphs. The station is 650 m above see level. It is equipped to accommodate 32 people and has drinking water and radio communication. This site is 60km from Liberia via Pan-American Highway kilometre 42, on partly asphalted and partly dirt roads.
The Pitilla Biological Station i son the Atlantic side, 600 m above sea level, and is totally surrounded by primary forest. In this zone the precipitation varies between 3,000 and 4,000 mm per year and is an excellent place for wildlife watching. The station is equipped to accommodate 20 people, and has drinking water and radio communication. Two of the existing paths are called El Nacho and La Campana. This station is located at km 9 from Santa Cecilia, where there are grocery stores.
The Guanacaste Conservation Area is in the northwest of the province of Guanacaste near the border with Nicaragua. The Pan-American Highway passes through the middle of Santa Rosa Park and Guanacaste Park. One can reach the main offices and the History Museum of Santa Rosa via San José and Liberia (256 km) along an asphalted road. The remaining internal thoroughfares are gravel and dirt roads so a four-wheel drive vehicle is required. Access to Nancite Beach and to Bolanos Islands is restricted.
In the Santa Rosa sector it is possible to visit La Casona, which has a museum, and the viewing point monument behind it. In this sector there are paths to El Indio Desnudo, Aceituno, Los Patos, Carbonal, Naranjo Valley and Naranjo Beach - Nancite Beach. In the Murcielago (bat) sector there is a path of El Generla. In Santa Rosa there are two camping sites, one near the offices and another near the History Museum, with tables, washbasins and drinking water. On Naranjo Beach, Estero Real and Murcielago there are camping sites with tables, toilets and non-potable water.
The Dry Tropical Forest Research Centre is located near the main offices. It is an important international centre for ecological studies of this ecosystem. It has accommodation for 72 people, laboratories, meeting rooms and a library, and is equipped with a computer system.