Almost the whole of this protection zone is taken up by the La Selva Biological Station. The station is run by the Organization for Tropical Studies (OTS), a consortium of universities from the United States and Costa Rica.
La Selva is made up of evergreen primary forests with a great diversity of plants which receives some 4000 mm of rain per year. The vascular plants consist of 2,000 species of which 400 are trees. The wild tamarinds (Pentaclethra macroloba) - the most common species - , the tonka bean (Dipteryx panamensis) and the jicaro (Lecythis ampla) are a few of the giants of the forests, always overrun by lianas, epiphytes and mosses. The crabwood (Carapa guianensis) is one of the most common trees in the swamps. The great many palms and Araceae (mainly epiphytic plants) in the undergrowth is very impressive.
The animal life is also very rich. There are over 400 bird species (almost half the birds in this country), including the bicoloured antbird (Gimnopithys leucaspis), an inhabitant of the undergrowth that feeds mainly on army ants (Eciton burchelli).
The 116 mammals include the white bat (Ectophylla alba), and among the 123 amphibians and reptiles are the poison dart frog (Dendrobates pumilio). There are 43 recorded fish species, including the delicious tasting very common cyclid (Cichlasoma dovii). 1600 isnsects have been recorded, including 35 grasshoppers and 479 butterflies.
La Selva and the northern part of Braulio Carrillo National Park form an altitudinal transect between 35 and 2,906 m, which includes 4 life zones, a fact which is of particular importance for conservation, because 20-25% of the birds, besides other taxa, move at different altitudes along this biological corridor.
La Selva is one of the most important and best known research centres in Tropical America. The United States National Academy of Sciences has designated it as one of the four best sites in the world for research into tropical forest diversity. It has laboratories, a library, conference rooms, a dining room, cabins, dormitories, a shop and other facilities.
La Selva Protection Zone is located in the lowlands of the northeast of the Atlantic Basin, th the confluence of the rivers Sarapiquí and Puerto Viejo. Within this protection zone there exists a network of paths leading to sites of scenic, biological and scientific interest. One of them goes into Braulio Carrillo National Park as far as the Barva Volcano and several refuges where it is possible to spend the night.